Volvo penta 5.7 engine cuts out at 4600 rpms

[Cramos]

This is a 2003 motor. I recently had the oil, oil filter and fuel filter changed. I haven't had any problems since I bought it brand new. I store it indoors and have it winterized. It worked fine at the end of last year and now it cuts out at 4600 rpms it cuts out when in nuetral as well as when it's driving on the water. It will cut out until it hits 4400 or 4500 rpms and then it will pick speed up back to the 4600rpms and then does it again repeatedly. I would really appreciate any tips. I just dropped it off at the mechanics shop last night and there stumped they thought it was cavitation but I had my prop and skeg repaired and it's still doing it. Also the fact that it does it when I rev it up in neutral kills the cavitation theory.
Please help. Thanks

 

[RicardoMarine]

I guess my first question would be..... why are you operating this engine at 4.4k rpm and above in the first place??????
This is close to your WOT RPM!


Perhaps have diagnostics run.... see if the knock sensor is talking to the ignition module, and asking it to cut back TA.
Our member Chris, on one occasion, found that incorrect spark plugs were causing the knock sensor to pick up on a knock.

Look at your engine model specific wiring schematic.... see if the system incorporates a Rev Limiter.

Have the shop perform a fuel pump pressure test.

Pull the feul tank pick-up tube and remove the anti-siphon valve, and see if there is a fuel flow restriction.

Use the P of E... process of elimination.... one item, and one item only until you isolate the problem.

.

 

[Cramos]

Hi Thanks for the quick response.
It's probably running at 8o% throttle to get to 4600 rpms. There's a lot of throttle left. I appreciate the suggestions and will pass them on to the mechanics. They just started working on it a few minutes ago.
Thanks

I guess my first question would be..... why are you operating this engine at 4.4k rpm and above in the first place??????
This is close to your WOT RPM!


Perhaps have diagnostics run.... see if the knock sensor is talking to the ignition module, and asking it to cut back TA.
Our member Chris, on one occasion, found that incorrect spark plugs were causing the knock sensor to pick up on a knock.

Look at your engine model specific wiring schematic.... see if the system incorporates a Rev Limiter.

Have the shop perform a fuel pump pressure test.

Pull the feul tank pick-up tube and remove the anti-siphon valve, and see if there is a fuel flow restriction.

Use the P of E... process of elimination.... one item, and one item only until you isolate the problem.

.