90 ELPT 4S
This one has me super stumped. Literally pulling my hair out!
Just got the boat so I’m unsure when it last ran correctly. Apparently the prior owner was having the same issue (but conveniently left that part out until after the sell).
- Engine starts, idles and cruises at low throttle (2-3000 rpm)
- Issue occurs after cruising around at 4-5000 rpm and coming off throttle. As soon as you pull back, you will start feeling a miss and the engine will no longer throttle up. Once I settle back to 3000 rpm or below, it smooths out but if I try to accelerate again, rpms jump and it bogs/misfires the entire time.
What I’ve inspected/replaced:
- FSM float
- Fuel lines
- Fuel filters
- Spark plugs
- Drained gas; old fuel looked fine. Good color and no separation after sitting.
Old plugs were black and I have noticed some improvement since replacement. I was able to ride around at 4500/~20mph with no issues for 15-20 minutes. As soon as I throttled down, the miss came back BUT if I throttled up it would clear and go back to cruising fine. I did this several times before it eventually refused to throttle up again.
Pulled the plugs and they’re all uniform (black around the bottom and tan/white up top). I honestly can’t tell of the miss is related to too much or not enough fuel.
What am I missing here? I occasionally get a single fault beep when trying to accelerate while it’s missing but that’s it. It’s never died or refused to start up after sitting.
On muffs, I get zero issues. Will hum at 3000 rpm. I did put it in gear and was able to experience the miss momentarily but it’s much harder to replicate with no load.
I feel like this has to be something electronic once the engine is at temp as it always seems to run the best after sitting but it could just be a coincidence.
Anything I should be checking on the FSM? Faulty TPS maybe (I would think that would affect idle and low throttle)?
It seems so strange that the issue occurs as soon as I throttle down to ~3500.
This one has me super stumped. Literally pulling my hair out!
Just got the boat so I’m unsure when it last ran correctly. Apparently the prior owner was having the same issue (but conveniently left that part out until after the sell).
- Engine starts, idles and cruises at low throttle (2-3000 rpm)
- Issue occurs after cruising around at 4-5000 rpm and coming off throttle. As soon as you pull back, you will start feeling a miss and the engine will no longer throttle up. Once I settle back to 3000 rpm or below, it smooths out but if I try to accelerate again, rpms jump and it bogs/misfires the entire time.
What I’ve inspected/replaced:
- FSM float
- Fuel lines
- Fuel filters
- Spark plugs
- Drained gas; old fuel looked fine. Good color and no separation after sitting.
Old plugs were black and I have noticed some improvement since replacement. I was able to ride around at 4500/~20mph with no issues for 15-20 minutes. As soon as I throttled down, the miss came back BUT if I throttled up it would clear and go back to cruising fine. I did this several times before it eventually refused to throttle up again.
Pulled the plugs and they’re all uniform (black around the bottom and tan/white up top). I honestly can’t tell of the miss is related to too much or not enough fuel.
What am I missing here? I occasionally get a single fault beep when trying to accelerate while it’s missing but that’s it. It’s never died or refused to start up after sitting.
On muffs, I get zero issues. Will hum at 3000 rpm. I did put it in gear and was able to experience the miss momentarily but it’s much harder to replicate with no load.
I feel like this has to be something electronic once the engine is at temp as it always seems to run the best after sitting but it could just be a coincidence.
Anything I should be checking on the FSM? Faulty TPS maybe (I would think that would affect idle and low throttle)?
It seems so strange that the issue occurs as soon as I throttle down to ~3500.