Need advice troubleshooting a 1999 Mercury 40hp ELPTO 2 stroke, 3 cyl. 20ft pontoon.
Won’t maintain over 2000rpm on open water. It will cruise along at 1200rpm, 4mph all day, but as soon as I throttle up, it will climb to around 2000 for a bit, sometimes even up to 3000 for a brief second. But then starts dropping down and eventually die unless you back off the throttle.
History: Ran good last year once warmed up, but started hard and super cold-blooded. I had one carb that dripped fuel when motor was trimmed up at the dock. Ran good, up to 17mph @ 5500rpm once warmed up though.
I rebuild the carbs over the winter in hopes of fixing the extreme cold-bloodedness and carb overflow. The carbs didn’t look too bad once I got into them, but the float heights were way off. 17mm (compared to the 14mm factory spec ) and nowhere near level. Rebuilding the carbs helped the starting issues but now it will only run well at just over idle speeds.
Things I have checked: compression is good 118-120 across all 3 cyl. New plugs. getting spark on all 3 cyl. Primer bulb hardens as expected. Seems normal. Floats are set to FSM 14mm spec.
I am suspecting that it is not getting enough fuel or sucking air somewhere in the lines. Planning to replace all lines and rebuild fuel pump. Does this sound like a logical next step? Anything else I should be looking at?
Won’t maintain over 2000rpm on open water. It will cruise along at 1200rpm, 4mph all day, but as soon as I throttle up, it will climb to around 2000 for a bit, sometimes even up to 3000 for a brief second. But then starts dropping down and eventually die unless you back off the throttle.
History: Ran good last year once warmed up, but started hard and super cold-blooded. I had one carb that dripped fuel when motor was trimmed up at the dock. Ran good, up to 17mph @ 5500rpm once warmed up though.
I rebuild the carbs over the winter in hopes of fixing the extreme cold-bloodedness and carb overflow. The carbs didn’t look too bad once I got into them, but the float heights were way off. 17mm (compared to the 14mm factory spec ) and nowhere near level. Rebuilding the carbs helped the starting issues but now it will only run well at just over idle speeds.
Things I have checked: compression is good 118-120 across all 3 cyl. New plugs. getting spark on all 3 cyl. Primer bulb hardens as expected. Seems normal. Floats are set to FSM 14mm spec.
I am suspecting that it is not getting enough fuel or sucking air somewhere in the lines. Planning to replace all lines and rebuild fuel pump. Does this sound like a logical next step? Anything else I should be looking at?
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