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Engine Will Not Reach Full Revs till its been Running a While

ehlien

ehlien

Regular Contributor
I have an 83 50 HP 2 stroke Mariner
I recently rebuilt the carbs and fuel pumps to solve low idle stalling
Its much better now at very low speeds but still wants to stall at idle
I have the idle screws turned out about 1 3/4 turns
New issue is when I take off and the engine has not been at full throttle for a while
but even if warm, If I give it full throttle it will only rev to about 50%
After a while if I play with the throttle and tilt it eventually it will jump up to full revs . It may stammer a bit as its making this tradition but once I get to full revs and start running it has no problem throttling up and down . If I shut down for a brief period not problem when i start back up but if I shut down for a couple hours I'm back to square one. It also seems like the time to get the problem solved is starting to get longer each time.
Any ideas what the issue is????
 
I have the idle screws turned out about 1 3/4 turns
Click to expand...
Did you get to that point after finding the sweet spot...smoothest idle point? To me the problem sounds like there is still crap floating in the bowl causing intermittent blockage or the spark is fluctuating? Next time it won't rev to WOT check for loud, blue snapping spark at each spark wire.
 
You need to adjust the carb idle for best idle, warmed up, in gear, with the boat on the trailer or tied to a dock (so it won't trick you). Then, when you've found best idle, ad 1/2 turn OUT (CCW).

Jeff
 
Will check bowls but they were clean before. Will also check the in line fuel filter. Have not heard any sparking. If it is electrical why would I get intermittent sparking only when tryng to first get to WOT but then once there be able to throttle up and down with no problem?
 
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