Join Date: Apr 2008
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Atomic 4 troubleshooting an odd problem?
The boat I regularly crew on is powered by an Atomic 4 motor and we have an odd problem with it.
The motor normally starts up easily at the dock. Powers us out to the race course easily. It starts up easily after racing and powers us into the dock easily. It seems to idle well, and run well during all of this.
A couple of times each year we do longer deliveries, and schedules dictate that as much as we might like to sail, we end up motoring or motor sailing. We do not let the boat heel much if we are motoring. We run the throttle at about 75% when using the motor.
On the longer deliveries, when we end up motoring for long periods of time, the motor works fine, until we try to slow it down. As soon as we try to slow the motor it will often stall, or won't run slower. We either have to rev it up, or it wants to quit. It still runs fine at 75% throttle. If it stalls it is very hard to get started, to the point at times it won't start. If it does start it does not want to run unless rev'ed up, and even then it no longer runs as smooth as it was running before.
The problem does not appear to be heat related. When this happens, we have sailed the boat into dock (fun, especially a strange dock at night) left it for 7 hours until morning, and still had it showing the same problems. We got a tow out of the marina for that race because the motor still wouldn't run. Then after the race it fired right up, and we had no more issues until after the next 8+ hour motor-sail.
The engine is well maintained. New points, condenser, spark plugs, coil, the carb was rebuilt totally, and the problem still exists.
What do we try next?