Striper500
Seaman
- Joined
- Nov 20, 2005
- Messages
- 52
I recently purchased a boat with a troublesome motor. The engine and boat are a 1995 which were purchased in 1998 and not used too much. The engine has good compression on all four cylinders from 125-130. The motor starts easily, and once running it will have a loud popping sound that occurs once every 20 seconds or so. The engine has good plugs and plug wires. I spoke to the local OMC mechanic who told me that it could be the ear muffs and that the boat should really be tested in the water to create back pressure. Unfortunately the river was frozen today, but I did manage to submerge the lower unit in a 55 gallon drum - this did not help at all. Once the motor warms up it's least noticible at idle. But when the motor is revving at 2-3000 RPM's the boat shakes when it misfires. Any ideas here ? Anyone seen these symptoms before ? Where would you begin ? Carbs ? Coils ? Timing ?