Situation:
Owner brought his boat (1996 OMC Cobra SX) over for me to help with trouble shooting.
Engine Ford Windsor 351 rated at 265 HP
Flame Thrower Distributor and Coil
New carb, intake and exhaust manifolds.
Sypmtom: Missing at any RPM above idle but at idle it runs smooth as silk. No power, will not get above 3000 RPM. Engine has roughly 5 hours on it since a complete rebuild. Owner says has never ran right since rebuild. Rebuilder is out of business and gone.
Did all the usual troubleshooting and found no real issue. Decided to do a compression test, was shocked at results as ALL 8 cylinders are running 50 to 55 PSI compression. Did a wet test (oil in cyl.) and no real difference. (Maybe 5 psi improvement.) Did leak down, could not hear anything.
Thought possibly the were over tightened so backed them off until loose and re-did compression test, no difference. All 8 cyl still at 50 - 55 PSI.
I am at a total loss as to what the heck it could be and am thinking I may have to pull the engine and do a tear down to see what is happening but I REALLY do not want to.
Anyone have any thoughts on why all 8 lungs on a newly build 351 would be running such low compression.
Owner brought his boat (1996 OMC Cobra SX) over for me to help with trouble shooting.
Engine Ford Windsor 351 rated at 265 HP
Flame Thrower Distributor and Coil
New carb, intake and exhaust manifolds.
Sypmtom: Missing at any RPM above idle but at idle it runs smooth as silk. No power, will not get above 3000 RPM. Engine has roughly 5 hours on it since a complete rebuild. Owner says has never ran right since rebuild. Rebuilder is out of business and gone.
Did all the usual troubleshooting and found no real issue. Decided to do a compression test, was shocked at results as ALL 8 cylinders are running 50 to 55 PSI compression. Did a wet test (oil in cyl.) and no real difference. (Maybe 5 psi improvement.) Did leak down, could not hear anything.
Thought possibly the were over tightened so backed them off until loose and re-did compression test, no difference. All 8 cyl still at 50 - 55 PSI.
I am at a total loss as to what the heck it could be and am thinking I may have to pull the engine and do a tear down to see what is happening but I REALLY do not want to.
Anyone have any thoughts on why all 8 lungs on a newly build 351 would be running such low compression.