WOT rpm issue - 1990 Volvo Penta 431A I/O

[wp001]

I just bought the 1990 Carver 27' with twin 431A Volvo I/O 1 month ago. I am a beginner and just noticed that during last planing, the pitch of the port engine's drone was getting lower when reaching 2300 rpm, sounds strange. And the WOT rpm could not reach higher than 3000, while the starboard engine can reach 4000.

Also, starting the port engine when it's cold is easier than when it's warm. I used to need 5 tries to start it after a 15 minutes break.

So where should I start to find the cause?

-wp

 

[Scott Danforth]

welcome aboard.

2300 RPM is seriously low, either your lugging it down that far, or its starving for fuel. 4000 RPM is also low. both motors should hit 4500 RPM easy.

I would start with the basics, like compression, then fuel system.

at the top of the forums are stickies, and the top of the volvo forum is both an Adults only sticky and information for DIY'ers.

http://forums.iboats.com/forum/engi...es-outdrives/479879-adults-only-no-exceptions

specifically item 14 http://forums.iboats.com/forum/engi...ves/302506-list-of-possible-causes-of-low-wot

 

[jerryjerry05]

Boat in a slip or trailer?

Filters, change them.​

Pull plugs and see how they're burning?

Compression.

Timing, check dist.. See if the springs are allowing the advance to work.



Coil: see how hot it gets.

 

[wp001]

Thanks Scott and Jerry!

The boat is at dry dock. I will do the investigation as you suggested. Thanks!