I have a 1989 350 Mercruiser with a Rochester quadrajet carby. When I bought it, it had a Mr Gasket electric fuel pump. It started and ran very well until last weekend, when it started hesitating under load.
I found out that the inline fuel filter was blocked, but in the process, I pulled the positive lead out of the fuel pump.
I was a little concerned about having a electrical fuel pump sitting in the bilge where it would get wet, so I thought I would replace the pump with a mechanical pump for more reliability. Boy I was wrong. I installed a Speedmaster pump, that was rated at 6.5psi.
It started and ran in the shed.
When we put it on the water, it started fine, but as my son was letting it idle to warm up, it died and would not start again. At first I thought it must of been starving for fuel.
I got in, and eventually got it started with full throttle. It would then idle for a bit, but would cut out unless you accelerated.
The water was so smooth we didn't want to miss out, so we still skied. The ran fine under power, but would die at idle, and then be hard to start, requiring full throttle, like it was flooded.
We had just had our last ski, and went to start the boat to take it to the ramp, and there was a terrible grinding coming from the engine.
It sounds like it has grabbed a ring!
My theory is the new mechanical pump is putting out too much fuel pressure that has flooded the motor every time at idle, washing the oil from the cylinder walls, eventually causing it to grab a ring! Sound likely?
I found out that the inline fuel filter was blocked, but in the process, I pulled the positive lead out of the fuel pump.
I was a little concerned about having a electrical fuel pump sitting in the bilge where it would get wet, so I thought I would replace the pump with a mechanical pump for more reliability. Boy I was wrong. I installed a Speedmaster pump, that was rated at 6.5psi.
It started and ran in the shed.
When we put it on the water, it started fine, but as my son was letting it idle to warm up, it died and would not start again. At first I thought it must of been starving for fuel.
I got in, and eventually got it started with full throttle. It would then idle for a bit, but would cut out unless you accelerated.
The water was so smooth we didn't want to miss out, so we still skied. The ran fine under power, but would die at idle, and then be hard to start, requiring full throttle, like it was flooded.
We had just had our last ski, and went to start the boat to take it to the ramp, and there was a terrible grinding coming from the engine.
It sounds like it has grabbed a ring!
My theory is the new mechanical pump is putting out too much fuel pressure that has flooded the motor every time at idle, washing the oil from the cylinder walls, eventually causing it to grab a ring! Sound likely?
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Sounds like you'll first want to pull the spark plugs out to see what or if anything comes out both at rest and while turning the engine over.
