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Rough running optimax 200hp

E

english steve

Member
Hi guys hope you can help as a follow up from my last post I've gone through the engine if anybody has some pointers that would be great as I'm starting to go crazy.

So I have a 2001 optimax 200hp with 850 hours that's been rebuilt recently, I've just bought it ( after a rebuild ) and mounted it to my boat initially it wouldn't start - I found the high pressure pump was seized prob from being sat around for the last 6 months - so I bought and installed a new one then I found that it still wouldn't start and there was a lot of water in my fuel from the tank so I cleaned it out fresh fuel and it started.
I took it out to break it in and the more I listened to it the more I thought it wasn't running right.

the idle and normal running of the engine Is rough you can see the engine vibrating as if it's mis firing. So I put new spark plugs in and checked all the coils were producing a spark and they are,
the idle with no revs flickers from 640 to 850 rpm
so I started pulling the plugs off the fuel injectors to see if I could hear a change in engine note and cylinders 2,4,6 ( left hand bank ) when I pull the plug there was a very minor change hardly even noticeable. When I did the same on 1,3,5 it was very noticeable .
I swapped out the coil packs to see if that would make any difference and it doesn't. I pulled the injectors out and cleaned the mini filters in them I've put new fuel filters on

im thinking it's a fuel problem but what could effect just the left hand bank ??

Please please please ease help me !!! Is there any sense in what I'm saying ????
 
Get two fuel pressure gauges and hook one to the air rail and one to the fuel rail and report back with your findings. While running, purge the air rail with the fuel pressure gauge and look for fuel.
 
Right I've got my pressure gauge, and hooked it up the gauge is flickering between 70-100psi on the fuel and 70-90 psi on the air side there is also a bit of fuel in the air too
 
Fuel in the air rail....Tracker valve diaphragm has a possible hole and will make the engine run like crap.

You need to get better gauges......

Should be, depending on Year, 90psi on the fuel rail and 80psi on the air rail. The tracker valve keeps the 10psi differential.
 
Docksidemarineservices said:
Fuel in the air rail....Tracker valve diaphragm has a possible hole and will make the engine run like crap.

You need to get better gauges......

Should be, depending on Year, 90psi on the fuel rail and 80psi on the air rail. The tracker valve keeps the 10psi differential.
Click to expand...


Mol took the tracker valve apart it was full of grit but was also missing the spring in the tracker valve the diaphragm itself wasn't in the best of shape but doesn't have holes either

Also removed the air pressure regulator that was also cchoked up with grit in the filter
 
english steve said:
Mol took the tracker valve apart it was full of grit but was also missing the spring in the tracker valve the diaphragm itself wasn't in the best of shape but doesn't have holes either

Also removed the air pressure regulator that was also cchoked up with grit in the filter
Click to expand...

Really look at the tracker with a jewelers loop. That is what I do. If there is crap in the rails there is crap in the injectors. Pull the rails and All 12 injectors and have them cleaned. This service will be cheaper than a power head.
 
Hi thanks for the advice, since we last spoke I've bought and installed a good set of fuel rails complete with diaphragms I removed the direct injectors and tested them and also run carb cleaner through. I still have the same problem - the fuel and air pressure is bouncing and running rough. Any ideas ??
 
Please explain the fuel and air bouncing....A cheap set of gauges will bounce back and forth on the air and fuel rail...You should see 90psi fuel and 80 air. It could also be 100/90.....

You cannot clean the direct injectors you have to take them to someone who can properly test them and clean them.
 
Hi Chris the gauges are indeed a cheap set, they bounce between 80-100 psi on fuel side and 70-90 on air side.
I under stand the injectors don't get cleaned properly with my diy solution, however I have fitted used ones as well from the used fuel rails so is the same with the direct and fuel injectors replaced
 
I'd say your air and fuel pressures are fine. 90/80 psi

OK. Time to look at the reeds. You can remove the throttle plate assembly and run the engine. The TPS controls the RPM. As long as the TPS is not advanced the engine will run at idle. Now for the fun part....with the engine running and the throttle plate removed put your hand down by the reeds. If one or 16 are broken or missing you will feel air blowing on your hand.

(I had a 225 Opti with 16 broken and missing reeds. Ran like a bag of Sh*t )


If you have a CDS tool to use you can look for elevated intake air temps. If the air temp is up on the intake you have a bad reed. Assuming you do not have this tool you will have to do it the manual way outlined above.

I know your engine has a fresh rebuild but, have you checked the compression?
 
Docksidemarineservices said:
I'd say your air and fuel pressures are fine. 90/80 psi

OK. Time to look at the reeds. You can remove the throttle plate assembly and run the engine. The TPS controls the RPM. As long as the TPS is not advanced the engine will run at idle. Now for the fun part....with the engine running and the throttle plate removed put your hand down by the reeds. If one or 16 are broken or missing you will feel air blowing on your hand.

(I had a 225 Opti with 16 broken and missing reeds. Ran like a bag of Sh*t )


If you have a CDS tool to use you can look for elevated intake air temps. If the air temp is up on the intake you have a bad reed. Assuming you do not have this tool you will have to do it the manual way outlined above.

I know your engine has a fresh rebuild but, have you checked the compression?
Click to expand...

i checked the compresssion when I bought the engine,the comps were 100psi on each cylinder - it's done approx 1 hour running time since then !

i will check reeds today and get back to you ! I got a box of spares when I bought the engine and saw some reed valves there I wondered why at the time !

Thanks chris for your time and patience
 
Right I've run it up and can feel back draft within all three ports when feeling the reeds some make a little pop noise some don't.
It seemed to run smoother with the front case off too.

https://youtu.be/eEgl6q1mb7E


heres the video of it running


Im guessing this is prob my issue ? Would it be best to replace with oem reeds or some carbon fibre ones ?
 
You took the whole plenum off....I usually just remove the throttle plate.

Kneel down with a flash light and visually inspect the reeds. All of them.

I know you tried a couple of sets of Direct Injectors(air) But I would have them all tested anyway.
 
Docksidemarineservices said:
You took the whole plenum off....I usually just remove the throttle plate.

Kneel down with a flash light and visually inspect the reeds. All of them.

I know you tried a couple of sets of Direct Injectors(air) But I would have them all tested anyway.
Click to expand...



Ok will will go and have a look I know that damaged ones will be chipped etc but do the reeds need to be sitting flush ? And should I see through them ?

I will get the injectors cleaned and tested.
 
I also pulled the plugs and they were all extremely black and sooty- some were a little wet others were bone dry I'm also running the engine on Break in so it gets extra oil at the mo
 
Hi dockside, I dropped the boat off this morning as I felt I had taken it as far as I could. They've been in contact and said there's no failings shoneing on the computor and he reckons compressor is ok he's putting some more time in this afternoon to see if he can find the fault.
 
Docksidemarineservices said:
This is straight from Mercury
Click to expand...
WHERE IS THAT SERVICE BULLETIN?

My optimax is driving me crazy. My pressures are messed up- fuel is 114-115, air is low 90's. So that is not good. ALso, someone mentioned fuel spritzing out of air----I know exactly- its a super fine mist- and only a very small amount then gone. I suspect that the air regulator and the air diaphram are messed up- but i want to see this service bulletin.

I will remove the fuel rail tomorrow to take them apart. I just went thru the whole system- rebuilt the fuel pump, the VST, new filters, new plugs, cleaned out the strainer, had injectors cleaned- all 6 (I have 115hp), and it still stalls, idles rough, BUT runs like a champion WOT--its just idle and lower RPM that it sucks. I am just concerned about going to my fishing spot 30 minutes from boat ramp- and then having problems. Motor issues are not something you should procrastinate---it will haunt you big time.
 
Mtsaz said:
WHERE IS THAT SERVICE BULLETIN?

My optimax is driving me crazy. My pressures are messed up- fuel is 114-115, air is low 90's. So that is not good. ALso, someone mentioned fuel spritzing out of air----I know exactly- its a super fine mist- and only a very small amount then gone. I suspect that the air regulator and the air diaphram are messed up- but i want to see this service bulletin.

I will remove the fuel rail tomorrow to take them apart. I just went thru the whole system- rebuilt the fuel pump, the VST, new filters, new plugs, cleaned out the strainer, had injectors cleaned- all 6 (I have 115hp), and it still stalls, idles rough, BUT runs like a champion WOT--its just idle and lower RPM that it sucks. I am just concerned about going to my fishing spot 30 minutes from boat ramp- and then having problems. Motor issues are not something you should procrastinate---it will haunt you big time.
Click to expand...

any update on this issue MTSAZ??? I have a 200 opti doing the exact same thing!!!
 
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