I have a 2005 Volvo Penta 5.0 GL-E. Carbureted, bone stock. Powers a 19 ft Larson Senza.
I'm having an issue at high RPM. Basically, above about 3500 RPM, there is a noticeable intermittent stumble. I don't usually cruise around at those high RPM's, but I'll occasionally pour on the coals if I'm trying to get somewhere quickly ... or obviously when I'm trying to pull up a skier. If I back off of the throttle a little, the stumble disappears. The engine starts, idles, and runs perfectly below this RPM. Even at/above those RPM's the engine runs smoothly except when this stumble occurs.
My first thought is that the ignition is cutting out. It's cheap to do and should be done regularly, so I'm going to replace the cap and rotor next time I'm up at the lake.
A few months ago, we got caught out at a lake restaurant in a torrential rainstorm (fortunately we were inside). Although the automatic bilge pump was doing its job, a tremendous amount of water was in the bilge following this rainstorm. Me thinking that the pump would have expelled the water by the time we got back out to the boat after the storm, I took off without lifting the doghouse. When the boat had trouble getting up on a plane, I stopped and pulled the doghouse to reveal the water level up past the oil pan. This was with it floating still on the lake. With the nose high and trying to plane, I cannot imagine how high the water level was before I stopped to check. While I cannot tie this exact storm to the beginning of the stumble, I never noticed it before that time.
Outside of the cap/rotor (and verifying that the distributor doesn't have any corrosion or residual water in it), what else on the ignition system could be causing this? Should I also pre-emptively change the coil module? They are kind of expensive, so I'd like to skip that, if possible. I checked the plugs last year and verified the correct gap. I guess it could be a wire or a failing plug, though. Being that this is a split-second intermittent stumble, that leads me away from any type of fuel delivery issue.
Thanks in advance for any advice on what you might check without just firing the parts cannon at it.
I'm having an issue at high RPM. Basically, above about 3500 RPM, there is a noticeable intermittent stumble. I don't usually cruise around at those high RPM's, but I'll occasionally pour on the coals if I'm trying to get somewhere quickly ... or obviously when I'm trying to pull up a skier. If I back off of the throttle a little, the stumble disappears. The engine starts, idles, and runs perfectly below this RPM. Even at/above those RPM's the engine runs smoothly except when this stumble occurs.
My first thought is that the ignition is cutting out. It's cheap to do and should be done regularly, so I'm going to replace the cap and rotor next time I'm up at the lake.
A few months ago, we got caught out at a lake restaurant in a torrential rainstorm (fortunately we were inside). Although the automatic bilge pump was doing its job, a tremendous amount of water was in the bilge following this rainstorm. Me thinking that the pump would have expelled the water by the time we got back out to the boat after the storm, I took off without lifting the doghouse. When the boat had trouble getting up on a plane, I stopped and pulled the doghouse to reveal the water level up past the oil pan. This was with it floating still on the lake. With the nose high and trying to plane, I cannot imagine how high the water level was before I stopped to check. While I cannot tie this exact storm to the beginning of the stumble, I never noticed it before that time.
Outside of the cap/rotor (and verifying that the distributor doesn't have any corrosion or residual water in it), what else on the ignition system could be causing this? Should I also pre-emptively change the coil module? They are kind of expensive, so I'd like to skip that, if possible. I checked the plugs last year and verified the correct gap. I guess it could be a wire or a failing plug, though. Being that this is a split-second intermittent stumble, that leads me away from any type of fuel delivery issue.
Thanks in advance for any advice on what you might check without just firing the parts cannon at it.