Hello All,
I have a 1988 Mercury Black Max 150, Serial Number B251261.
The engine is running, but it is rough at low RPM (below ~ 3000 RPM),it isrunning good at high RPM and I think it has full power at top end. The roughoperation in the low range is bothering me.
Lots done already: Carbs cleaned, link&sync, new coils, wires, plugs,stator, trigger, switchboxes, new crank seals, new cylinder head gasket, ...
When I had the heads off, I could see some scouring in the cylinder walls, butnot sure how serious it is and if that is the reason for running rough at lowRPM.
Here are the compression and leakdown readings.
Note higher leakage rate on cylinder 4-6, but compression is good on allcylinders.
Is it really worth to re-build the engine? Or is myproblem somewhere else?
I have a 1988 Mercury Black Max 150, Serial Number B251261.
The engine is running, but it is rough at low RPM (below ~ 3000 RPM),it isrunning good at high RPM and I think it has full power at top end. The roughoperation in the low range is bothering me.
Lots done already: Carbs cleaned, link&sync, new coils, wires, plugs,stator, trigger, switchboxes, new crank seals, new cylinder head gasket, ...
When I had the heads off, I could see some scouring in the cylinder walls, butnot sure how serious it is and if that is the reason for running rough at lowRPM.
Here are the compression and leakdown readings.
Note higher leakage rate on cylinder 4-6, but compression is good on allcylinders.
Is it really worth to re-build the engine? Or is myproblem somewhere else?