Volvo Penta 5.0 will not rev up over 3000 rpms.

[rosssco27]

Hello all,
First time posting to the forum. I just replaced the engine in my 2003 25' steiger craft pilot house with a long block. When I am by myself the engine will not rev over 3000 rpms but it appears to run smooth with no issues and does not skip a beat. This past weekend I went out with 5 guys and the boat could not get on plane and would not rev over 2000 rpms. It will sit there and idle all day without any issue. As soon as the boat goes under a signifigant load it will not rev up. I have changed cap, rotor, plugs, and wires. Any advice would be greatly appreciated!

 

[bruceb58]

It is possible that you are stuck in SLOW mode which means that either the over temp switch or low oil pressure switch are faulty. This would limit RPMs to 2500.

How did you re-time your distributor?

 

[rosssco27]

Thanks Bruce. I have not heard of the slow mode, I will have to look into this. I reset the distributor with a timing light. I changed the timing while I was on the water after I realized it was not running correctly. Nothing seemed to help.

I also rain the boat off of an external fuel tank with new gas with no change. I also changed my fuel water separater with no change...

 

[bruceb58]

Carb or fuel injection? Which distributor do you have? If you have the EST, you have to put it into base timing mode to set the timing.

 

[rosssco27]

Fuel injection. Not sure which distributor I have. How do I tell? How do I put it in a certain mode?

On another note, I put a gauge on the fuel rail tonight. 50psi when I would turn the key on and engine NOT running. It would slowly lessen in pressure as I sat there watching it. When running the pressure would stay at 50psi. When I would remove the vacuum line off of the fuel pressure regulator it would go up to 55psi. I am not sure that is useful information but that is what I did tonight.

Pulling me hair out!

 

[Jammer864]

Check that the flapper valves (if installed) havent broken off and are partially blocking the exhaust where the Y pipe comes together and exit out the transom. I had something similar. Ran great and revved to max on the hose but in the water (under load) I couldnt get past 2000 RPM.