Mercury issues....

Thread starter #1
I have a 20 ft suntracker pontoon with a 50 hp merc 2 stroke on it. Never had a second of trouble out of it in the 2 years i haveowned it. Last time i ran it was thanksgiving weekend of 2011. Got it out the other day hooked the hose up and within 5 seconds of turning over it busted off fine. Revs up good and idles perfect. Went to put it in the water yesterday and it cranks fine but when i got out to the channel and gunned it, it went up to about 4000 rpm and then bogged down and shut off. IT did this several times and i was never able to get more than 4200 rpm out of it without it bogging and stalling. It will cruise around at 3000 rpms and idle fine. Any help wold be appreciated. Also we always use staybill or however you spell it in our fuel and usually put mid grade fuel. Last time i filled up i did it at a station that serves non-ethanol fuel. But it was probably mixed with a half a tank of 10% ethanol fuel.
 

bandit819

Senior Member
#2
Clean your carbs. Stabil does nothing to stop phase seperation in ethanol fuel. My yami did the same thing. Non- ethanol fuel will do better for you in the long run. Also if your not going to run your motor for a long time throw some seafoam in the tank run the motor till you know the seafoam is running through it, diconnect the fuel line and run all the fuel out of the motor. I'm not a mechanic, but that is what I do.
 
#3
Clean your carbs. Stabil does nothing to stop phase seperation in ethanol fuel. My yami did the same thing. Non- ethanol fuel will do better for you in the long run. Also if your not going to run your motor for a long time throw some seafoam in the tank run the motor till you know the seafoam is running through it, diconnect the fuel line and run all the fuel out of the motor. I'm not a mechanic, but that is what I do.
Ain't never figured this one out....but it seems to clog the high speed jet everytime !! Run fine on the hose, idle fine in the water, won't run under a load !!
 

rayjay

Senior Member
#4
The high speed jet is in the lowest part of the float bowl.
 
#5
Well good luck with this problem. My 150 was doing the exact same thing. I got a call from Dalton Marine yesterday that the compression was 0 on the # 1 cyl. Between $2500-$4200 to repair on a 1995 motor. Would be $300 to tear the head down to get a true estimate. WOW I did learn one thing not to buy a motor by just listening to it idle. This thing would idle great and run just on plane great
 

boneboy96

The High Flying Mod
#6
I had same issue on a Suzuki 75 and I never could figure it out. Thought it might have been an electrical problem. Motor would rev up 6000 rpms+ in neutral, put it in gear and couldn't get much more than about 2850 rpms B4 it bogged down.
 
#7
Do not mix fuels. Mixing E with non E will cause all sorts of crud in the tank to soluablize and be carried into motor. The filters will not catch it and with heat and evaporation the crud reforms and clogs up jets and injectors.

Run only non E gas with stabil and seafoam in it. Run the motor often.
 
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