Tohatsu MFS6B 2010.
started engine cold. I was running at medium throttle with a large load in the dinghy. i had been running for about 10 minutes when a loud hit pitched whine / screeching started. It seemed to be coming from under the cowling. I slowed, put in neutral and shut down. i did not remove the cowling but checked the prop for fishing line. All seemed clear. I restarted and no longer had the noise. I continued at a slightly more moderate rate for another 5 minutes to complete my trip. No recurrence of the noise. I checked oil. It was low but still at the dipstick so I topped off.
A few hours later I used the engine for 10 minutes at medium throttle with no noise. Power seemed fine.Shut down. Finally once more I used the engine at medium throttle (started cold) but after about 5 min the whine started. I just slowed to idle speed and the noise stopped And continued my trip for another 5 minutes. Dark so removing the cowling was not practical.
I am guessing it might be something related to the pull start but so far have not seen anything through visual inspection after removing cowling While running but without the noise. There are particles that look like belt dust seen on a motor with a belt driven alternator but this has been the case before so no new unusual accumulation as far as I can tell.
thank you,
harry
started engine cold. I was running at medium throttle with a large load in the dinghy. i had been running for about 10 minutes when a loud hit pitched whine / screeching started. It seemed to be coming from under the cowling. I slowed, put in neutral and shut down. i did not remove the cowling but checked the prop for fishing line. All seemed clear. I restarted and no longer had the noise. I continued at a slightly more moderate rate for another 5 minutes to complete my trip. No recurrence of the noise. I checked oil. It was low but still at the dipstick so I topped off.
A few hours later I used the engine for 10 minutes at medium throttle with no noise. Power seemed fine.Shut down. Finally once more I used the engine at medium throttle (started cold) but after about 5 min the whine started. I just slowed to idle speed and the noise stopped And continued my trip for another 5 minutes. Dark so removing the cowling was not practical.
I am guessing it might be something related to the pull start but so far have not seen anything through visual inspection after removing cowling While running but without the noise. There are particles that look like belt dust seen on a motor with a belt driven alternator but this has been the case before so no new unusual accumulation as far as I can tell.
thank you,
harry