Engine RPMs Fluctuating

[platinumedge]

Hello All. It's been awhile since I posted. I haven't had my boat in the water for over a year now. I winterized it and "brought it back to life" a couple of months ago - no real issues. However, the engine rpm's fluctuate quite a bit. At idle it runs up close to 3,000, then back down, then back up. When I open the throttle to about 3,500 it bounces back and forth between 4,400 and 3,100. Both fuel pumps are operating good and main filter is new/clean. Note that I was having some problems with raw water pump as it was drawing air. But after I resolved that the fluctuation issue remains. Any recommendations?

Thanks!

 

[Scott Danforth]

And what are you working on? There are many Volvo Penta motors

 

[platinumedge]

Sorry, it's in my signature. It's their 5.8L EFI motor.

 

[Scott Danforth]

Check fuel pressure
Check compression
Pull injectors and have them cleaned
Check IAC , replace if the pintle is stuck

 

[Rene.golik]

Check fuel pressure
Check compression
Pull injectors and have them cleaned
Check IAC , replace if the pintle is stuck

What if the RPM is fluctuating on the Tach but not in real time?? Volvo Penta 5.7GSi PEFS

 

[Scott Danforth]

What if the RPM is fluctuating on the Tach but not in real time?? Volvo Penta 5.7GSi PEFS

start your own thread

 

[Rene.golik]

start your own thread