I have a mercury500 thunderbolt 50hp starts up fine won't idle or open up all the way.
It has 120psi on all four cylinder so I was taking off the carbs to rebuild when I noticed a 2x1/2 inch hole to the left and under the upper carb guess I'm just wondering if I should fix it or what would cause...
I have a mariner 25hp will only start at full throttle.
When I try to slowly let off gas backfires from propeller and dies.
I have cleaned an rebuilt the carb new fuel line all the way to the gas tank
Slator,power pack,and coils good.good compression and no sheared key on the flywheel
O and oil...
