Got a Bayliner 2552 w/ a Mercruiser 4.3 V6. It had been sitting for 25 yrs and the motor was frozen/seized. I poured diesel to free up the motor. The motor was freed up but will not start. It does turn over. I sprayed ether and it helped but will not combust. Got new battery, starter and new plugs. I was wondering if I should pour high octane booster into the spark plus holes to help start the motor?
what is the compression?
if you dont have a minimum of 130 psi in all cylinders, you really need to pull the motor apart to fix. 99.99% of the time, even if you get a frozen motor spinning, the rings are still stuck, the valve are stuck in the heads and the bearings have been eaten up by either rust or the acids in the oil
did you rebuild the fuel system? sitting for 25 years, everything from the tank to the carb will need to be mechanically scrubbed clean. did you pull the fuel sender and clean the tank? if not, do so. did you pull the fuel pickup tube and anti-siphon valve and clean them? if not, do so. did you pull the carb apart and chase every passage with a fine wire to make sure they are clean, then re-assemble per the manual to set the linkages and float correctly? if not, do so
you need compression, spark and fuel at the right times for combustion
