Carver 356 RPM issues

[cpoint]

OK, final update on this long running problem. It turned out to be clogged fuel injectors. Although they were replaced 3 years ago after first bad fuel extraction. I had ended up extracting fuel for second time after fuel injectors were replaced with new ones. and also had it filtered twice. Than the original shop that was working on it, started going after different parts. The new guy I found listened to the history of the problem, made his analysis and tested what he needed to, and said it was the fuel injectors. He removed them had them cleaned at a local shop (3 days to thoroughly clean them), ad they did find lots of crap 5-10 microns (my filter is 25 micron). 2 of them were too far gone to be cleaned, but they had 2 they had cleaned before that they switched for me. Anyway, after installing the cleaned fuel injectors in to the engine. and also damaged wiring was discovered for port tachometer and fixed. We took it out ran it for 3 hours, both engines running normal, both tachometers going all the way up to top. not violent moves on port tachometer as before, both tanks burning equal amount of fuel. We are good to go finally. One problem is bottom is fouled up pretty badly, so need to get that cleaned to get top speed. Also mechanic said I should not run it hard with dirty bottom, It may damage the engine. so I am trying to schedule cleanup in the next few days to test it out to max. I am hoping tank is now clean, as I have filled and emptied number of times since the bad fuel issue. Keeping fingers crossed. Or I may just get the injectors cleaned every season maybe if it happens again. At least now we know that is the issue.

[g36]

Hoping for the best for you, maybe your finally done with this mess.

[Viper]

Just my two cents here; I mentioned before how important it is to go through a systematic diagnostic process which I see now didn't happen with your previous mechanic. Had he performed an injector flow test which is easy to do right on the engine, and compared the results to spec or simply to each injector, this problem would have been solved a while ago. This is the difference between throwing all kinds of money on parts and procedures in hopes that one of them will solve the problem, and performing proper tests that will point to the actual culprit.

Glad you finally got it solved and that you can get some boating done. Fingers crossed that the tanks won't be a constant headache.

[DCharles]

Change the spark plugs on both engines!!

As soon as you ever notice the throttles at differ positions it’s a sign the plugs are on there way out. Best to change dist cap and rotor as well. Also ensure plug wires are within resistance specs.

[cpoint]

Source of the post Just my two cents here; I mentioned before how important it is to go through a systematic diagnostic process which I see now didn't happen with your previous mechanic. Had he performed an injector flow test which is easy to do right on the engine, and compared the results to spec or simply to each injector, this problem would have been solved a while ago. This is the difference between throwing all kinds of money on parts and procedures in hopes that one of them will solve the problem, and performing proper tests that will point to the actual culprit.

Glad you finally got it solved and that you can get some boating done. Fingers crossed that the tanks won't be a constant headache.

Viper, Thanks. I know what you mean, unfortunately, due to my lack of knowledge in mechanics (know more now than before), they took advantage of it I believe. So far we put 9 hours since the last fix, and this is most we went trouble free, and it is fun not seeing tach go crazy, not to mention getting same power out from both engines. I too am hoping the tanks wont cause more issues, but at least we know now the issue was and most likely will be fuel injectors if it happens again, we'll just bite the bullet and get them cleaned. But we definitely enjoyed it last 3 days being a long weekend today we are getting bottom cleaned, so we can throttle up more later part of the week when we head out.

[cpoint]

Source of the post Change the spark plugs on both engines!!

As soon as you ever notice the throttles at differ positions it’s a sign the plugs are on there way out. Best to change dist cap and rotor as well. Also ensure plug wires are within resistance specs.

DCharles, mine are bit off, but I think the cables needs adjustment, they never been adjusted.