Mercury 1F06201EL

by Julian Eley
(Bristol UK)

My 6hp Mercury packing up on me halfway out of Keyhaven (UK) harbour. Fortunately, the direction I was pointing in at the time meant my centreboard got stuck in the mud, so the current did not take me into the closely moored boats and I didn't have to panic to get the sails up. Model number 1F06201EL. There were no previous problems and it was about 1hr use from a full service and over winter storage. Symptoms? I ran it at low revs with no problem. The issues started as I speeded up with what sounded like misfiring. This got steadily worse, so I opened the throttle more, which made the failure worse till the engine quit, and I could not restart it. I sailed for some 3 hours before returning to the slip. Alongside the jetty, I tried the motor, and it started first pull. Now, a day later, I put it in the test water butt. It started the second pull, it ran sweetly, and I could see water squirting out the underside. Increasing the revs, I could hear unevenness like there was a missfire and exhaust smoke was noticeable. Increasing the revs, the unevenness was very noticeable, and the engine was struggling to maintain the revs. Dropping back to tickover and things seemed fine. This was repeatable, though I am sure If I kept the revs up, the engine would quit. I suspect it is electrical, with something failing as it heats up. Has anyone any ideas or suggestions to pin down the problem?