mercery 8hp idle rough

7 point

Senior Member
I have a 8 hp mercery 2 stroke it idles rough and bogs down just before it plains out but runs good at low speed and after it plains what could cause this?
 

1gr8bldr

Senior Member
Your moving fuel through the circuits so your jets are open, but likely partly blocked. This will cause a lean condition so don't run it much like this. Seafoam type products only work if your partly blocked. Fully blocked and they do nothing. My testing showed no danger in running some through a carb. However, no sense in an entire tank of seafoam mix. Or diluting it in a full tank. See if you can bottle feed it bypassing the tank. Any tank with a fuel line will allow this but often a boat motor or chainsaw will not. If the carb is easy to get to, cleaning the jets might be easier. Careful not to enlarge the holes and don't forget the emulsion holes on the sides of the idle jet
 

1gr8bldr

Senior Member
You might also check the float bowl. If the fuel was left on over winter, it will evaporate out of the bowl, however the bowl will keep replenishing itself, eventually draining the entire tank if left long enough...... except that the oil in the mix does not evaporate. Therefore, you could have a bowl full of oil
 
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