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Need help with my F-225 fuel problem

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Fishhawaii

New member
I know some dealer or boat owner has had this problem or heard of one like it before I'm in dire need of assistance and ideas before I just give up.
last October my 2004 F-225 lost RMP while leaving the dock. When I advanced power lever to 2100 RPM it would just bog down. Called a mechanic and ran the boat at the dock. Put it under load and it worked fine. Left the dock and got 6000 RPM for almost an hour. Then RPM dropped off and and boat would barely run above idle. 1/2 hour later boat ran fine. When we put it on the trailer it would not get above 1500 RPM.

Mechanic said VST screen was probably clogged so we removed it. it was full of white chalky stuff. Cleaned the VST screen and boat ran great for 14 hours. Same problem returned but have more depth now. When accelerating, sometimes at a RPM range near 2000, or 3000 or 5000 the boat suddenly bogs down. If you continue to push up the throttle RPM decreases but when you pull the throttle back, at some point RPM increases again. When it happens engine does run rougher than normal but one minute later smooth as can be at 6000 rpm. Put a fuel guage on the rail pressure at 42 lbs then suddenly drops to 20 then boat runs real rough at 10 shuts down. Ran on an external tank same problem. Have done diagnostic several times no problems show up.

Took the VST screen off again and found it full of white powder. Found the bottom of the VST tank corroded. replaced the VST tank. Same problem. Took all fuel (clean) out of the tank. Replaced pick up and fuel tank indicator. Replaced all filters on the engine several times, replaced racor several times. Changed the ball, All has had no effect on the problem. last week decided to change the HP fuel pump. Pump looked good, clean could not get any deposits out of it. Finally ran the boat today and the problem is the same. Seems to be totally starving for fuel (sometimes). Initially would not get above 1500 rpm then 2200, then 3100 then suddenly it accelerated normally and got 5700 RPM and ran smooth. As soon as I pulled it back it would not get above 2000 again for the rest of the trial.

The real symptoms, run the motor in a bag. looks and runs smooth. Put it under load and it seems at some point (low RPM) to start running a little rough. Advance the throttle and everything feels normal until a certain RPM and then RPM decreases rapidly and engine starves for fuel. Bogs sometimes backfires or just sputters. Pull throttle back and at some point RPM increases to a point.

I guess in re-thinking the problem, most probably the severely clogged VST screen was probably never the problem or it was just part of a problem. The only thing left is the fuel regulator and I'm not sure if this would have these symptoms or not. I think having the pressure drop on the rail eliminates injectors, injector pumps and the like. I think. Of course today it ran at almost full power without skipping a beat for several minutes.

If I can eventually get past this problem I'll be faced with doing a major on the corroded exhaust that I have. Yamaha's are wonderful....cant wait.
redface.gif
While looking for this problem I did find some severe corrosion in the exhaust. Looks pretty bad. Here is a video in case anyone has some input on this problem or if they could be related.
Thanks

http://www.youtube.com/watch?v=7vXC7jkJ7W0
 
Last edited:
While it is running poorly and the fuel pressure drops, pinch off the return line after the regulator and see if the problem goes away. If you are getting excessive white powder in the vst and fuel lines. Look at your racor filter mounts. They are probably the reason.
 
Docksidemarineservices said:
While it is running poorly and the fuel pressure drops, pinch off the return line after the regulator and see if the problem goes away. If you are getting excessive white powder in the vst and fuel lines. Look at your racor filter mounts. They are probably the reason.
Click to expand...

Thanks Chris, So if the problem goes away after pinching the return line the regulator is porting too much fuel?

We only found powder twice and the bottom of the tank has some corrosion that looked like it might have been the source. I am extremely interested in the Racor mount thing as we changed the racor previously to this entire problem beginning. We have changed the racor filter element probably 3 times since this started. We see no white residue or anything else in the fuel or any filters. I physically have pounded the racor element on a towel and nothing has ever showed. Here are pictures of my VST screen the first time it was cleaned and the corrosion on the bottom of the tank (which was replaced).

attachment.php
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What about fuel lines on the engine are they ever a problem? I'm not sure if you have seen the exhaust problem but please take a look at my video and tell me what you think.
Thanks,
Rick
 
Yes on the return line.

The filter in the VST is 2 micron. Unless you install a 2 micron Racor the filter is doing nothing to stop the white powder. If the filter mount is deteriorating it doesn't matter what size filter you install. If the tank is corroding it may be time to replace it. Is the fuel tank aluminum?
 
Yes on the return line. I will try that next time we water test. that is good to know but still not sure if I understand. So that fuel would just be returned to the tank?

The filter in the VST is 2 micron. Unless you install a 2 micron Racor the filter is doing nothing to stop the white powder. If the filter mount is deteriorating it doesn't matter what size filter you install. If the tank is corroding it may be time to replace it. Is the fuel tank aluminum?[/QUOTE]

The racor element and holder are brand new. The tank is plastic and spotless. New puck up tube. We changed the bottom of the VST tank back in November. cleaned everything, boat got somewhat higher RPM for awhile but would still bog down at RPM's above 4000. Sometimes and I think the hint might be in the sometimes. Yesterday first at 1500, then 2500, 3000, then next thing you know we are doing 5700 and the engine sounds perfect. let it run like that for awhile and pull it back. next time you push the throttle up, advancing the throttle above 1500 engine just bogs again and backfires and coughs. Pull the throttle back slowly and RPM catches to 2200 but bogs as soon as the throttle is advanced.

We have run the engine under load with the diagnostic on, NADA we run it with the pressure indicator in the rail and when the boat bogs the pressure drops to somewhere below 25. I would have thought that means the problem is before the rail but maybe not?
Thanks for hanging in there we me. as this is very frustrating.
Rick
 
The problem may just be in the regulator then. The backfire is a lean backfire from lack of fuel. When the engine starts to loose power, pinch off the return. this will tell all. Do it with the fuel pressure gauge attached, If the pressure does not come up, try pumping the fuel primer ball.
 
Docksidemarineservices said:
The problem may just be in the regulator then. The backfire is a lean backfire from lack of fuel. When the engine starts to loose power, pinch off the return. this will tell all. Do it with the fuel pressure gauge attached, If the pressure does not come up, try pumping the fuel primer ball.
Click to expand...

Yah we have tried that several times with no change. The ball is normally pretty full of fuel but squeezable. When you squeeze it will create more pressure and you can feel the fuel running thru the ball.

Thanks again, I'll try it when I can get the boat in the water again. Chris Have you ever seen the dry exhaust corrosion before? Have you ever removed a F225 power head?

Rick
 
Not sure that affects that year Yamaha, but there have been plenty of stories about ethanol fuel deteriorating the fuel lines in you run ethanol gas?
 
aliboy said:
Not sure that affects that year Yamaha, but there have been plenty of stories about ethanol fuel deteriorating the fuel lines in you run ethanol gas?
Click to expand...
Boy were you right on!

Here is the latest on my Yamaha F-225. On Saturday, we went to the harbor with every intent of fixing the engine. My mechanic set up to run on an external tank, plugged in the computer, and installed a fuel pressure gauge on the rail. Then we laid the cover on as best we could and took the boat for a ride. Pushing the power up felt normal until reaching 3600 RPM where then advancing the throttle resulted in decreased RPM, and sometime a backfire. The fuel pressure would always start at 42 lbs and always drop to the 20 to 30 psi range. The value when the pressure began to drop became the mark of the highest RPM range. It was an obvious fuel problem as pulling the throttle back slowly would result in a temporary rise in RPM. +/- 200. Pushing the throttle full forward always resulted in the engine producing the same RPM. The weird thing about this problem is it never seemed to happen in the same RPM range. One day, or one minute 1500 RPM and next time 4000 rpm. Once in a while the engine would run normally. My mechanic was convinced it was the float in the VST not allowing the fuel to fill the tank. I argued that I would agree if it happened at the same RPM each time. Having the pressure drop each time made me realize that the problem was somewhere between the front filter (where the external tank hooked-up), and the fuel rail (where you can measure pressure).

He agreed to put the boat on the trailer and take the fuel system apart. Once we got there we traced the entire fuel system and looked for possible problems. We removed the VST cover and found a little crud (again) and cleaned the screen. Then we systematically went thru the system. There are several check valves in the fuel lines and they become a suspect place for build-up or restrictions. With an air nozzle we blew air thru each line along the fuel path. There is a fuel line that comes out of the top of the VST and up over the engine toward the right side (looking forward) rail. These rails are nothing more than tubes that feed fuel to the injectors. When we blew in this line (in the direction of fuel flow) it spit fuel back at us. We tried it several times and it seemed like the check valve at the top of the engine (rail to rail) wouldn’t let fuel pass. We removed the other end of that line where it goes into the stbd (right) rail and blew air into that line. It seemed like a cloud of white junk shot out the other side. In retrospect if I have to do this again I would try to hold a jar on the other side to catch the contents. Be advised that fuel did shoot everywhere so watch your eyes. At that point going back to the other side and blowing on the line out of the VT tank it no longer kicked back fuel and the check valve now appeared to be free. We also found a small slice in one of the vacuum hoses and cut of and replaced the end. We then put the engine back together and methodically strapped all of the fuel lines to make sure each one was clamped. Once done, we ran the engine in the bag (no load) and it ran fine like always did. That is a complex issue for me because it seems like fuel is fuel and this type of problem should always show up. In this case it only happened when running under load.

Put the boat back in the water and it runs like a champ. No hesitation and 6100 RPM. So I believe it was some deposits from the corroded VST (ethanol) tank clogging the check valve between rails. Put 5 hours on it yesterday and she runs great.

Just a note of thanks to all who read or replied to my posts on these web sites. Your education and assistance helped me figure this very frustrating problem out. These forums are invaluable and you guys in the know should be commended for taking the time to answer our posts. Thank you!

On another quick note. It sounds like this problem is not over yet. I spoke to a guy who maintains a ton of Yamaha engines and he said they had a major problem with many clogging the VST screen. He said they have changed all the hoses on these engines between the racor and the filter on the front of the engine (in the tube). It appears that hose de-laminates from the continued use of Ethanol fuel. Thanks again aliboy as this is the real underlying problem.

 
Fishhawaii said:
Boy were you right on!

Here is the latest on my Yamaha F-225. On Saturday, we went to the harbor with every intent of fixing the engine. My mechanic set up to run on an external tank, plugged in the computer, and installed a fuel pressure gauge on the rail. Then we laid the cover on as best we could and took the boat for a ride. Pushing the power up felt normal until reaching 3600 RPM where then advancing the throttle resulted in decreased RPM, and sometime a backfire. The fuel pressure would always start at 42 lbs and always drop to the 20 to 30 psi range. The value when the pressure began to drop became the mark of the highest RPM range. It was an obvious fuel problem as pulling the throttle back slowly would result in a temporary rise in RPM. +/- 200. Pushing the throttle full forward always resulted in the engine producing the same RPM. The weird thing about this problem is it never seemed to happen in the same RPM range. One day, or one minute 1500 RPM and next time 4000 rpm. Once in a while the engine would run normally. My mechanic was convinced it was the float in the VST not allowing the fuel to fill the tank. I argued that I would agree if it happened at the same RPM each time. Having the pressure drop each time made me realize that the problem was somewhere between the front filter (where the external tank hooked-up), and the fuel rail (where you can measure pressure).

He agreed to put the boat on the trailer and take the fuel system apart. Once we got there we traced the entire fuel system and looked for possible problems. We removed the VST cover and found a little crud (again) and cleaned the screen. Then we systematically went thru the system. There are several check valves in the fuel lines and they become a suspect place for build-up or restrictions. With an air nozzle we blew air thru each line along the fuel path. There is a fuel line that comes out of the top of the VST and up over the engine toward the right side (looking forward) rail. These rails are nothing more than tubes that feed fuel to the injectors. When we blew in this line (in the direction of fuel flow) it spit fuel back at us. We tried it several times and it seemed like the check valve at the top of the engine (rail to rail) wouldn’t let fuel pass. We removed the other end of that line where it goes into the stbd (right) rail and blew air into that line. It seemed like a cloud of white junk shot out the other side. In retrospect if I have to do this again I would try to hold a jar on the other side to catch the contents. Be advised that fuel did shoot everywhere so watch your eyes. At that point going back to the other side and blowing on the line out of the VT tank it no longer kicked back fuel and the check valve now appeared to be free. We also found a small slice in one of the vacuum hoses and cut of and replaced the end. We then put the engine back together and methodically strapped all of the fuel lines to make sure each one was clamped. Once done, we ran the engine in the bag (no load) and it ran fine like always did. That is a complex issue for me because it seems like fuel is fuel and this type of problem should always show up. In this case it only happened when running under load.

Put the boat back in the water and it runs like a champ. No hesitation and 6100 RPM. So I believe it was some deposits from the corroded VST (ethanol) tank clogging the check valve between rails. Put 5 hours on it yesterday and she runs great.

Just a note of thanks to all who read or replied to my posts on these web sites. Your education and assistance helped me figure this very frustrating problem out. These forums are invaluable and you guys in the know should be commended for taking the time to answer our posts. Thank you!

On another quick note. It sounds like this problem is not over yet. I spoke to a guy who maintains a ton of Yamaha engines and he said they had a major problem with many clogging the VST screen. He said they have changed all the hoses on these engines between the racor and the filter on the front of the engine (in the tube). It appears that hose de-laminates from the continued use of Ethanol fuel. Thanks again aliboy as this is the real underlying problem.
Click to expand...

Just to let you all know, I also spent the 3500.00 on the famed lower leg corrosion repair. Mine was not very bad at all. So my F-225 Yamaha is finally perfect? Today I should be fishing in an event that is one pf my lifetime favorite things to do. We are a competitive group of friends and its a once a year deal. Here I sit at home yet again as the fuel bogging issue returned yesterday. No one on the island has a clue as to why this is happening but I clean the VST filter and it runs for somewhere around 20 hours or so and starts the bog thing all over. The screen is not dirty so the problem has to do with something we are touching or moving while doing the process.
To date I have:
1. Removed and cleaned the fuel tank (spotless before i started)
2. Replaced the anti syphon valve and pick-up tube
3. Replaced the fuel indicator and float
4. Replaced the racor unit.
5. Replaced the VST Tank
6. Replaced the F filter (several times)
7. Replaced the high pressure pump
8. Run the boat on an external tank
9. Run the boat with a fuel pressure gauge on the rail. When pressure drops to 20 psi boat runs like crap.
10. Replaced every fuel filter several times (not dirty)
11. Cleaned the VST screen 8 times. (mostly not dirty)
12. Blown out every fuel line.
About the only thing left I can think of is taking this beautiful 225 Yamaha 4 stroke and shoving it very deep into the engineers (who designed such a piece of Crap) exhaust cavity. Does anyone know who I can call from Yamaha and discuss this? Please don't say a dealer as their is no one qualified to work on this engine for 2500 miles.
I guess now I need to install a vacuum gauge to see what the pressure is doing before the engine.
Do yourself a favor don't buy one.....ever!
 
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Yamaha builds an extremely good product. Not designed to be serviced by the owner.

If you are losing fuel pressure and the VST and screen are clean, then you have lack of fuel flow to the VST. Make sure the low pressure supply pump is working. Make sure you do not have a kink in the fuel line somewhere between the primer ball and the VST. Make sure there are no restrictions on the fuel supply side in the VST including the vent.
 
Docksidemarineservices said:
Yamaha builds an extremely good product. Not designed to be serviced by the owner.

If you are losing fuel pressure and the VST and screen are clean, then you have lack of fuel flow to the VST. Make sure the low pressure supply pump is working. Make sure you do not have a kink in the fuel line somewhere between the primer ball and the VST. Make sure there are no restrictions on the fuel supply side in the VST including the vent.
Click to expand...

Thanks Chris,
Actually only been two of the best outboard guys around working on the engine. I just watch but when you keep throwing money it gets frustrating and you start looking to the promised land for help. As you know, these intermittent problems like most will drive people nuts and I believe you are on the right track. Every time we clean the VST we wiggle the problem and it works for awhile or we are sucking air slowly and takes 20 hours to have an effect. While the fuel lines have no visible kinks,what do you think about installing a vacuum gauge on the front side to see of the pump is actually working or if we have a restriction. Some folks tell me if the engine runs, the lift pump is working. I am considering another thousand in injectors and replacing all the hoses and check valves on the engine. Do you know if the internal hoses are susceptible to damage from ethanol?
Some say only the external ones.
Can you please tell me how the VST is vented as this is a first for me. When the problem exists, I have run the boat several times on an external tank and it makes no difference. So my main focus has been on the area from the front filter to the VST where I too believe the problem exists. Any help would be appreciated.
While Yamaha might make a good product, their support sucks. All I have been looking for is a number I can call and have someone (don't care if they are indian and reading from a book) say ok do this first. I understand they want me to take it to their tecks but the closest one is 2500 miles away. I simply can't.

I believe there are many hints.
Boat never stops running, ever
RPM range where the bogging starts differs all the time.
When it's not happening I get 6000 screaming RPM's.
When the problem is happening squeezing the ball makes no difference
When the problem is happening pinching the fuel line makes no difference.
Computer has never shown any faults.
When the fuel pressure on the rail drops to 20 lbs the engine runs rough.

This time we had to bring the boat in for 2 hours at 2000 rpm. It ran extremely rough. When we opened the engine the fuel boxes were saturated with fuel and the #1 sparkplug was fouled. All other plugs showed a lack of fuel. I believe this is a result of running the engine with low fuel pressure and not part of the problem. Any feelings? Could one sticky injector cause all the fuel to dump? I am concerned about long term damage from running the engine like this or a possible hydro-lock??
Thanks for your help as again any will be appreciated.
Rick
 
If the fuel pressure is dropping it is not the injectors. You have a fuel supply problem to the High pressure pump or the high pressure pump itself is bad. Disconnect the vacuum line to the regulator and retest for the pressure loss.
 
I was thinking about offering you a Hawaiian vacation but I might need the money to get my boat repaired. Maybe a Hawaiian care package with sun, sand, mac nuts and pineapple will help in the dead of winter.
This thing has become very expensive and frustrating and I am more determined than ever to fix it. I really don't have a choice as there is no one here very qualified. I do have two great mechanics who are outboard guys and have done all of my work. They are quite capable but frustrated too. I have been told to install a temp vacuum gauge between the racor and the engine as well as the fuel pressure guage on the rail. If/when the problem happens the vacuum should show
1. The life pump not operating normally.
2. Restriction in the fuel system
3. Air leak in the lines or system.

Would you agree that this is the best next step? My main focus is that the pressure drops from 40 to 20 and then the boat runs like crap. I need to find out why that happens and I believe when we clean the VST we jiggle something that makes it work for awhile. 20 hours later it returns. Anyone with ideas is welcome to respond as I am running out of them as we speak.
Thanks Chris,
Rick


Docksidemarineservices said:
Just a little too far for me to travel to.....
Click to expand...
 
Geeze... Having read this thread I feel for you Fish. There is nothing more maddening that chasing a ghost. I'll toss in my 2 cents worth as I've no idea what it could be since you've tried about everything... Have you gone all the way back, beyond all of the filters you've changed and looked at the fuel feed line that sits at the bottom of the main gas tank? Sometimes that feed line has a filter on it at the end of that hose that sits on the bottom of the main tank. The sloshing around of the fuel in the tank will clear it over and over and then when under way as it is drawing fuel it gets clogged over and over. I've seen a few chase ghosts for countless dollars only to find that a stupid filter at the end of the fuel pick up in the bottom of the tank is causing the problem. If you pull that fuel line in the main gas tank and there is a filter on the end of it, pull that damned filter, throw it away, and put the line back into the tank. There's no need for that stupid little filter it with a Racor inline followed by all the others along the way. A $5 filter that never should have been put there could be causing all of these random fuel flow problems.
 
deepsea21 said:
Geeze... Having read this thread I feel for you Fish. There is nothing more maddening that chasing a ghost. I'll toss in my 2 cents worth as I've no idea what it could be since you've tried about everything... Have you gone all the way back, beyond all of the filters you've changed and looked at the fuel feed line that sits at the bottom of the main gas tank? Sometimes that feed line has a filter on it at the end of that hose that sits on the bottom of the main tank. The sloshing around of the fuel in the tank will clear it over and over and then when under way as it is drawing fuel it gets clogged over and over. I've seen a few chase ghosts for countless dollars only to find that a stupid filter at the end of the fuel pick up in the bottom of the tank is causing the problem. If you pull that fuel line in the main gas tank and there is a filter on the end of it, pull that damned filter, throw it away, and put the line back into the tank. There's no need for that stupid little filter it with a Racor inline followed by all the others along the way. A $5 filter that never should have been put there could be causing all of these random fuel flow problems.
Click to expand...

Thanks, Actually we have ran the engine off of an external tank twice when the problem is happening and no change. When we first started with this we pulled the tank (which was spotless) and cleaned it with alcohol and vacuumed it out. Then we changed the pck-up tube and the antisyphon valve as well as the fuel level indicator in the tank. last night we found that the return line to the VST had some white deposits in it and it appeared like the lift pump was a little weak. We changed the pump and it seems to run a little better but I will not know until I can run it under load. In the end we will change all of the fuel lines including the tank to racor to engine. It's getting pretty expensive but I'm lucky to have a couple of friends do most of the work. I am also waiting for a vacuum gauge to measure the suction in the front of the engine while monitoring the fuel pressure on the rail. Hopefully that will tell me if I have an air leak, blockage or if the lift pump is operating normally. I'll keep you posted and thanks for the encouragement.
 
Fishhawaii said:
Thanks, Actually we have ran the engine off of an external tank twice when the problem is happening and no change. When we first started with this we pulled the tank (which was spotless) and cleaned it with alcohol and vacuumed it out. Then we changed the pck-up tube and the antisyphon valve as well as the fuel level indicator in the tank. last night we found that the return line to the VST had some white deposits in it and it appeared like the lift pump was a little weak. We changed the pump and it seems to run a little better but I will not know until I can run it under load. In the end we will change all of the fuel lines including the tank to racor to engine. It's getting pretty expensive but I'm lucky to have a couple of friends do most of the work. I am also waiting for a vacuum gauge to measure the suction in the front of the engine while monitoring the fuel pressure on the rail. Hopefully that will tell me if I have an air leak, blockage or if the lift pump is operating normally. I'll keep you posted and thanks for the encouragement.
Click to expand...
have you replaced needle valve and seat in the vst.Make sure vent to vacuum box is clear and breathing.
 
I had a similar problem with a 225 4 stroke(2005). It was fuel injectors, and dealer replaced them all. Now getting 5800 RPMs but sometimes won't WOT. I'm running 3 225s. 480 hours. VST and rail pressure were checked by dealer's best mechanic for 40 hours of work until back fire was eliminated. Imagine the bill I had?
 
Fishhawaii said:
Boy were you right on!

Here is the latest on my Yamaha F-225. On Saturday, we went to the harbor with every intent of fixing the engine. My mechanic set up to run on an external tank, plugged in the computer, and installed a fuel pressure gauge on the rail. Then we laid the cover on as best we could and took the boat for a ride. Pushing the power up felt normal until reaching 3600 RPM where then advancing the throttle resulted in decreased RPM, and sometime a backfire. The fuel pressure would always start at 42 lbs and always drop to the 20 to 30 psi range. The value when the pressure began to drop became the mark of the highest RPM range. It was an obvious fuel problem as pulling the throttle back slowly would result in a temporary rise in RPM. +/- 200. Pushing the throttle full forward always resulted in the engine producing the same RPM. The weird thing about this problem is it never seemed to happen in the same RPM range. One day, or one minute 1500 RPM and next time 4000 rpm. Once in a while the engine would run normally. My mechanic was convinced it was the float in the VST not allowing the fuel to fill the tank. I argued that I would agree if it happened at the same RPM each time. Having the pressure drop each time made me realize that the problem was somewhere between the front filter (where the external tank hooked-up), and the fuel rail (where you can measure pressure).

He agreed to put the boat on the trailer and take the fuel system apart. Once we got there we traced the entire fuel system and looked for possible problems. We removed the VST cover and found a little crud (again) and cleaned the screen. Then we systematically went thru the system. There are several check valves in the fuel lines and they become a suspect place for build-up or restrictions. With an air nozzle we blew air thru each line along the fuel path. There is a fuel line that comes out of the top of the VST and up over the engine toward the right side (looking forward) rail. These rails are nothing more than tubes that feed fuel to the injectors. When we blew in this line (in the direction of fuel flow) it spit fuel back at us. We tried it several times and it seemed like the check valve at the top of the engine (rail to rail) wouldn’t let fuel pass. We removed the other end of that line where it goes into the stbd (right) rail and blew air into that line. It seemed like a cloud of white junk shot out the other side. In retrospect if I have to do this again I would try to hold a jar on the other side to catch the contents. Be advised that fuel did shoot everywhere so watch your eyes. At that point going back to the other side and blowing on the line out of the VT tank it no longer kicked back fuel and the check valve now appeared to be free. We also found a small slice in one of the vacuum hoses and cut of and replaced the end. We then put the engine back together and methodically strapped all of the fuel lines to make sure each one was clamped. Once done, we ran the engine in the bag (no load) and it ran fine like always did. That is a complex issue for me because it seems like fuel is fuel and this type of problem should always show up. In this case it only happened when running under load.

Put the boat back in the water and it runs like a champ. No hesitation and 6100 RPM. So I believe it was some deposits from the corroded VST (ethanol) tank clogging the check valve between rails. Put 5 hours on it yesterday and she runs great.

Just a note of thanks to all who read or replied to my posts on these web sites. Your education and assistance helped me figure this very frustrating problem out. These forums are invaluable and you guys in the know should be commended for taking the time to answer our posts. Thank you!

On another quick note. It sounds like this problem is not over yet. I spoke to a guy who maintains a ton of Yamaha engines and he said they had a major problem with many clogging the VST screen. He said they have changed all the hoses on these engines between the racor and the filter on the front of the engine (in the tube). It appears that hose de-laminates from the continued use of Ethanol fuel. Thanks again aliboy as this is the real underlying problem.
Click to expand...


I have aver exactly the same problem with the same 2004 225hp. Did you solve the problem? I'm desperate on this ...
 
I just replaced the vacuum canister and all three small aluminum check valves. Still same problem. Pressure on the rail is around 44 psi. Injectors replaced after originals were cleaned several times...same problem or even worst after this
 
While I can see it has been several years since this was an active post, was there ever a solution? I have the same issues happening to a 2004 Yamaha F225. Been going on for a year and a half. Think it's fixed and two months later it's back. I can't stand an intermittent problem that can't be fixed. How do you trust your rig? I'm happy to spend the money, if I know what to do. I'd love to hear how it all went for you.
 
I did everything. Cleaned everything but the final solution was when I took care of each hose connections and tight them properly. Fuel pressure is the key. Check every single hose connection and tight
kappajohn said:
While I can see it has been several years since this was an active post, was there ever a solution? I have the same issues happening to a 2004 Yamaha F225. Been going on for a year and a half. Think it's fixed and two months later it's back. I can't stand an intermittent problem that can't be fixed. How do you trust your rig? I'm happy to spend the money, if I know what to do. I'd love to hear how it all went for you.
Click to expand...
 
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