Marine: Boating, Sailing, PWC, GPS and Navigation - 4.3l OMC runs rough after it is warm

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KAB
08-12-05, 12:29 PM
I have a 1986 Sea Swirl. It has a 4.3l OMC engine. I recently took it out of storage and found a number of things wrong. I have fixed everything but when I start it up it will run great until it gets warm then it starts running rough. I initiially thought it might be bad fuel and drained the tank. The problem continued with the new fuel. I have replaced the plugs, coil and rotor cap. The rotor looks good. I haven't replaced the plug wires but they don't show a break when tested. I had a complete tune-up at the beginning of last years boating season (2004).

I am beginning to think it is fuel related again. Possibly the carburator? It only does this when it gets warmed up. If I have it out of gear and rev the engine it backfires and dies. If I put it in gear I can take it up to 3k rpm's but it is missing badly. The choke is working properly.

Anyone have suggestions?