Logo

engine won't rev past 3000 rpms under load

chasmans

New member
I have twin 305 chevys 228 hp inboards . Having problem with both engines not wanting to rev past 3000 rpms. Will not get up to plane. Carbs rebuilt correctly new plugs, wires ect . Have not replaced cap but looks good. Engine starts right up. Checked antisiphon valve got crud out of that. Any ideas ?
 
What, if any, changes have been made to the boat or to the engines just prior to this?


Hull bottom clean?
Engines in full tune?
Progressive and Total Advance correct as per the OEM curve?
Fuel good?

If the ignition system is not delivering the correct Progressive and Total ignition advance, no gasoline engine will produce it's potential output.
 
Hull bottom clean Engines in full tune fuel is good . Havn't checked advance yet but engines are set a right timing. It happens in both engines .
 
The fact that you found crud in your anti-siphon valve is a major clue. Did you check it again after running the engines up? Also, it could be that you have a screen on the bottom of the fuel pick-up tube, and it's getting clogged. If it was my boat, I would be suspect of the entire fuel system.
 
Back
Top