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2010 Honda BF225 Hard to start

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mechaniczman

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I have a 2010 Honda BF225, hard to start since I bought it. I purchased it with 260 hours it currently has 290 hours on it. Prime the bulb, turn the key, wait for the high pressure pump to pressurize, 3 seconds on each crank, it normally stumbles to life on the 4th crank sometimes 5,6,7 tries. If I shut it off and IMEDIATELY restart it, it will start and I can do that as many times as I want but if I wait a bit and try to start it it will not start on the first or second try. It rarely ROARS to life most of the time it just stumbles to life. It also occasionally will surge when cruising around 3k RPM I can feel the boat surge and watch the rpm gauge fluctuate about 200rpm.

I did have the engine die once it got on plane twice after letting it sit in the water off for 30 mins. I replaced the anti drain back valve on the fuel tank and it has not done that since, seems to hold prime better as well. Just drove it 40 miles offshore to the Gulf Stream.

Parts replaced/work performed:
Inspected fuel pickup in tank
Anti drain back valve
Fuel water separating filter in hull
Checked/Tightened all fuel hose clamps/connections
High and low fuel filters
Removed, cleaned, resealed and adjusted float in VST with all new oem orings and screw
Watched the low pressure pump move fuel into a container, removed pump and plunger moves without issue but with some force
Removed fuel rail and pressurized high pressure pump to look for leaks on the injector nozzles
Vacuum tank (was busted)
6 OEM NGK spark plugs
Both thermostats
Oil and filter
Water pump kit
Replaced and adjusted throttle cables
Compression is 190+ on all 6 cyl
Injector resistance, and fuel bypass solenoid resistance is within spec
 
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Just one observation - I've always kept the engine cranking on start up until it fires, unless it's more than 10 seconds or so. The 3-second "bump" starting is probably not good for this engine, or the starter motor.

I would recommend that you pull off the top piece of the engine where the fuel line goes in through that big black grommet and make sure you don't have any restrictions or kinks there. Salt and gunk will often build up and restrict the fuel line.
 
Chawk, i will experiment with 10 second cranks more but it doesnt seem to attempt to start. It acts like it wants to start more when I do short bursts. Are you talking about the grommet at the front of the motor where all the cables, fuel line and wires come in at? If so I have had that off to install a NMEA cable to the Garmin unit and it all looked fine no corrosion. The motor runs good at full throttle, and no alarms.

My fuel pressure tester adapter for this motor broke so I have to get another one and will post back after I check that.
 
Does this engine have two positive wires, one large and one smaller one to the battery isolator or battery? I have seen people connect this ssmaller wire to the starter stud instead of back to the battery, espeacially when making up custom battery leads. This method ddoesn't supply enough voltage to the EFI system during cranking.Check your motor hasn't been modified in thkis manner.
 
All of the wiring to the starter is factory, confirmed with a diagram. Has 2 new batteries and cranks over strong. I checked fuel pressure and have 55psi running and key on engine off. 25 psi with fuel pump off and holds steady.
 
Something is not right here. It should hold pressure at 40psi after key on and engine not running and 40psi at idle. I had two AK1 engines on the same boat have a very similar problem back in about 2011. Being in warranty at the time and having checked everything I convinced Honda to let me try another ECM on one of the motors, it fixed the problem as did the replacement ECM on the second motor.
 
I was wondering if its been like that ever since it was installed. Its not the original engine on the boat. I have the original purchasers info on the engine title. I do believe the pressure is too high, the manual states 40-48 psi. I would think that it would hold that even with the key off but it drops to 20-25. I actually witnessed the engine start on the first try one time on the lake the other day but ive only ever seen it do that once. Maybe its getting better the more I run it. I am going to test the pressure regulator and then remove it to check for a blockage on the return lines. There is an issue with it because the engine still surges at cruising speed intermittently.
 
I checked fuel pressure again today, and its worse fuel pressure is 70psi engine is running extremely rich, i can smell it strong in the exhaust, and rough idle. It has never run this bad. I have ordered the fuel pressure regulator and screen.
 
I installed a new fuel pressure regulator and screen and the fuel pressure is now 40 psi and holds steady when the engine is off. Put about 20 hours on the motor runs good but still stumbles to life on the 2nd or 3rd try most of the time if its been sitting off. If I turn it off and restart it immediately then it fires up first tap of the key.
 
I wonder if this might have something to do with engine temperature sensor? If it's reporting that the engine temp is higher than actual ambient at cold start that might affect enrichment and/or ignition timing.
The same might be true for the inlet air temperature sensor.

Most auto systems have voltage vs.temperature "step" tables to consult for testing temp sensor values but I don't know about Honda outboards.

The engine temp and intake air temperatures should agree at cold start and then begin separating as the engine warms.

Any chance of hooking up Dr. H to check?

Also, could it just be a matter of excess resistance in the sensor/ ECM wiring or connections?

Just throwing it out there for discussion.

Good luck.
 
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My 04 225 has always started right up after running or sitting for a couple months, I would think an experienced Honda tech could fix your issue in an hour or two.
 
Ok, i still haven't gave up on this engine. Still hard to start, an intermittent rough idle on the hose, surging when on the lake around cruising speed but runs good at full throttle. Fuel pressure a solid 40. Rechecked compression 180-205 pulled the plugs and noticed the left bank and right bank are not running equal. Port bank looks nice and brown on all 3 and starboard bank looks lean and oil deposited. It does burn oil but no noticeable smoke. I did notice the original plug should be an NGK IZFR6F-11 and these are NGK IZFR6K-11 for some reason but wouldn't explain why one bank is off. Only thing i can figure that would cause fuel trim issues on one bank would be 3 bad injectors or possible pcm issue. Maybe i need to check cam timing.

This engine had denso plugs in one bank and ngk in the other when i bought it i believe someone else was trying to fix it.
 
Yes, the spark plug difference would make me think that someone was trying an experiment to address a problem. It would also make me wonder WHAT ELSE did they try?

I was going to suggest a compression test but I re-read your post and see that you have already done that. "190psi all 6 cylinders". So....

It seems like with only 260 hours that it shouldn't have lost a great deal of compression but I don't have the specs for this. The fact that they're all even is surely a good thing but I do wonder about the oil consumption you say that you see.

I hate to say it but could this engine have been overheated at some point and one head...the one burning oil...took a worse hit than the other? I would love to see what engine history is stored in the ECM. If overheat is indicated then I would definitely suspect oil getting past the valve guides on that bank.

The surging could very well be the computer trying to solve an imbalance in cylinder contribution but, of course, the question is why?

You might want to do a cylinder leakage test to see if anything jumps out but I think some Dr.H time might answer some questions on this one.

Just my opinion and I hope you get it sorted out.
 
Sorry, completely spaced on your revised compression readings. 180psi is 87% of 205psi so your spread from highest to lowest is at 13%. When I was in the engine overhaul business we condemned anything over 15% difference. A leakage test is definitely in order in this case.

Again, just my opinion.
 
Its possible it was overheated or run low on oil. I have only owned it about a year so dont know the history or have a honda scan tool. I have 300 hours on it now and it burns about a quart every 10 hours the cylinder with the lowest compression of 180 had the most oil deposits on the plug i believe port side cylinders were 185 190 and 205 and starboard was 180 185 and 190
 
These engines should not burn any oil. Even my 07 BF 225 with 2200+ hours doesn't burn any oil. So, yes, a leak down test is called for as Jimmy indicated. Next, adjust the valves precisely. Could be that your exhaust valves are too tight and possibly compromised the valve stem seals.
 
This is all pointing to O2 sensor, I said right from the start, I have had this issue on 2 engines of this generation, both were fixed with a new ECM and new O2 sensor. My guess is your surge is around 4000 RPM. This surge is caused by a "lazy " O2 sensor, the surge is caused by a slow reaction to mixture adjustment and does NOT log a fault code because the ECM is seeing a signal, even though incorrect.The hard start is almost certainly ECM related, BUT you can live with it if you don't want to go to this expence, it will not get worse, just a bit tough on t he starter.
 
Ok that makes sense, i thought the o2 had been replaced before i bought it but not 100% sure. I ordered a new oem o2 sensor and a new set of spark plugs. I will install those and see how it does.
 
I installed the 02 sensor and it didnt make a change in how it ran on the hose. Was rough idle, shaking from misfiring, hesitation when giving throttle. So i warmed the engine up and ran the majority of a can of aerosol seafoam through the intake at 2k rpm let it hot soak and then revved it up quite a bit. I removed the intake cover to clean out excess seafoam and fired it back up. I was skeptical but it idled perfect, no missfire no shaking no more obnoxious air sucking in the intake or loud exhaust. So then i installed new spark plugs but have not had time to run it on the lake. I will in about a week or two. It still doesnt start on the first try but it runs perfect on the hose.
 
I got a chance to run it on the lake, i changed the oil, installed an OEM honda primer bulb assembly and re did all my fuel line connections on the boat. The engine seems to have more power gets up on plane faster and hit a new top speed record of 41 got the engine to rev to about 5700. It is consistently starting on the second try, which we have determined is likely the PCM which i can live with that for now as it is much better than it has been in the past. However it still does not like being at exactly 4500 rpms, it surges by 1-200rpm. Not effected by engine temperature. Even when accelerating or decelerating past the 4500 mark you feel a hiccup. Anything over or under it runs perfectly. Maybe throttle position sensor has a bad spot. The only thing i noticed is there is a red X on my Garmin nmea2000 tachometer between 2k and 4500rpm i wonder if it is getting a bad signal from the crank position sensor. Im pretty much at the point i need the honda software or test each sensor with a meter to go any farther with it.
 
Never seen a red X on a Garmin, what model is it?.Just use you boat and enjoy it, it seems to me you're over thinking after the issues you had. I get this often with customers.
 
Haha you know it probably is, just double checked the manual and vtec kicks in at 4500 and disengages at 4300 and thats about where it surges. If it will run with the vtec solenoid unplugged i may un plug it temporarily just to test that theory. The Garmin unit is a new 943xsv the only thing hooked up to the nmea network is the engine. The x appears in the tach between 2k-4500 but still shows rpm.
 
Unplugging the Vtec will cause an alarm, just use the boat. I can't explain the X, if there is no alarm and the engine is running okay I would leave it alone. Check the Garmin manual online,it might tell you what it means
 
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