RPM high speed fluctuation SR230 2003

[Anders]

My SR230 2003 255 hours MR1 port engine dont get full rpm, ECU?

Cylinder #2 spark plug gets ”black”, and have been fluctuating before, now it is more steady bad. The oil level is a bit high, in both engines, so I dont think that is the problem. The oil looks good, only pure oil and no smell of gas. I have own it since 2005.

I have:
1) changed all the spark plugs, no change
2) removed airfilter (some oilsplash on it), no change
3) checked compression on all cylinder and they are good (12,5, 12,0, 12,0, 12,5 kg/cm3)
4) analyzed and cleaned all injectors, less then 2% diffrence before and after, switched place, no change
5) live tested injectors on the rail not bolted to the engine (as @Beachbummer suggest in this thread https://jetboaters.net/threads/mr1-ecu-or-injector-or-something-else.27700/) and the spray looks good, (see pics, couldnt upload movies due to wrong file extension and have only iPhone)
6) short test up on land and the rpm is okay
7) checked the impeller housing and no visibel diffrence between the two (see pictures)

If the live test looks good, can it still be ECU problem? I havent yet switched between starboard and port engines and not sure how to do it, but perhaps it is self-explanatory when open up the box?

Or could it be bad oil ventilation that @WREKS writing in thread Bad ECU | JetBoaters.net - The World's Largest Jet Boat Forum!

Happy for any advice that can solve the problem!

 

[Babin Farms]

I would try switching the ECU's just to just verify that they are or aren't the issue.

 

[Anders]

Here is how spark plug for cylinder 2 looks. It looks like getting to much fuel. Looks the same before and after switching the injectors.

 

[buckbuck]

I concur with @Babin Farms
Swap the ECU's and see if the problem follows.

 

[Anders]

Thanks for your advice, we swapped the ECU:s and the fluctuation moved to the other engine, so you where right! Now searching for a workshop in Europe that can renovate/replace it, do any one know if there is any in Europe?

 

[Anders]

Found Carmo in Nederlands, unfortunately on holiday until 15:th August, but they seems to be recommended by many in this forum

ECU computer Reparatie - revisie kosten 6 [REP6] - €429,34 : Carmo Electronics - Motorbike parts or electronics

Carmo Electronics ECU computer Reparatie - revisie kosten 6 [REP6] - Klik hier voor het Test/Reparatie formulier Revisie Ingegoten/Gesealde Injectie/Ontstekingsunit (ECU/ECM) Revisie van ingegoten/gesealde ECU/ECM units en ontstekingsunit met meer dan 2 bobine uitgangen. Dit bedrag betaalt u als...

www.carmo.nl

 

[buckbuck]

I am glad you isolated the issue and hope you can get it repaired soon.

 

[yu177536]

Get YDS and run diag active test to drop each cylinder if all performance well then ok, but if one cylinder drop (not going thru the test) then need to change spark plug (but you said spark plug new) then test ignition to see the plug give the spark. Possible low perf RPM is one of cylinder doesn't burn the fuel and make gas into the oil that is why you might see the oil level high doesn't matter you take it off.

 

[Anders]

Get YDS and run diag active test to drop each cylinder if all performance well then ok, but if one cylinder drop (not going thru the test) then need to change spark plug (but you said spark plug new) then test ignition to see the plug give the spark. Possible low perf RPM is one of cylinder doesn't burn the fuel and make gas into the oil that is why you might see the oil level high doesn't matter you take it off.

Thanks for your answer yu177536, it was the ECU, the workshop (Carmo) testet it and confirmed the problem, now they have repaired the ECU so problem solved