1997 60* Evin 90HP OIS. Past 2200 fades and dies under load.

[James R]

Carbs are cleaned and rebuilt. Sparks are good. Have tested in the pond using a clean tank and a 3/8 hose and bulb shoved into the tank fill hole to eliminate any restrictions. Starts and idles good but wont go much past 2200 before dropping off. Tried squeezing the bulb but the bulb remained firm and no change to performance. This motor has had the VRO removed and a Standard fuel pump fitted. This motor is fitted to a Toon so it is difficult to test much in the water.
So do we have an Ignition problem perhaps? Comps are excellent.
Any ideas would be gratefully received.
Thanks in advance,
Jim.

 

[Faztbullet]

Was the vapor separator removed? Is it a dual pump? It sounds like it may be fueled starved as I haven't see many conversions that was successful

 

[ob]

Try pushing in on the key primer before the engine drops off from 2200 rpm and see if it picks up. If so, it would indicate a fuel delivery issue. If it bogs even more look elsewhere for the issue. Otherwise as part of the carburetor rebuild I assume the linkage is all synchronized and adjusted to spec.

 

[James R]

Thanks guys. You both have given me a lot of food for thought. My suspicions were and still are that it is a fuel supply problem. Will investigate further along that track.

 

[James R]

This motor has had some serious monkeying. It has only one standard pump. Would replacing that with a VRO pump be a better option. Would only use the fuel pump side which is rebuildable as you know. The fuel pump assembly minus the VRO is still intact. I think it will be necessary to pull this motor off the boat to get good access. While I am in there I will clean the carbs to my standards and do the sync.Thanks again guys.