Thanks much for the feedback Frank.

I’m definitely aware of the turtlemotor’s tendency to breathe their own exhaust. The exhaust bellows on this motor are in good shape.

To your point, this one was running in a barrel with its cover off. I do also have a couple extra breathing holes under the handle in the cover to get more clean air in when the cover is on. Will try your suggestion and run it Sunday on the lake and see how it goes.

I did just run it again a moment ago. It runs great in the barrel when essentially level (highest setting on the tilt adjustment), but coughs pretty badly when on its lowest tilt setting in the same barrel 20 seconds later, nothing but the tilt setting changed….

I ran the motor today at the lake.

With the motor in the lowest trim setting (as if to put a boat on plane), it would barely run. Just sputtered and popped. Would not stay running long enough to get it in gear, and if I did, it did not have enough power to push the boat.

Put the motor on its highest trim setting and it purred like a kitten. Ran and started great that way, so we just ran around the lake and fished with the nose up. This was a no wake lake, so it really did not matter. In either setting, the lower unit was very low in the water due to the low transom on this boat.

I put the motor in a can this afternoon and shot a quick vid. I tilted the can to be able to get a similar angle to the transom. It behaved just like on the boat. Check the vid out. Breathing its own exhaust has no effect.

I do have a carb rebuild kit on the way. Only things I can think of now are a sinking float or something to do with the low speed needle and its seals. Both will be replaced soon.

https://www.youtube.com/watch?v=GVqiH6oJ4II

I finally fixed this issue and wanted to wrap this up. I must admit I feel pretty silly now that I know the answer.

First off, I did purchase a carb rebuild kit and rebuilt the carb (as opposed to the thorough cleaning I had given it previously). I do get a more firm bulb on the fuel line now, so I think the new float in the kit was more than worth it.

Running it with the rebuilt carb was exactly the same, so that narrowed it down to ignition issues as suggested above.

At this point, I elected to put in new points and condensors and check that everything is exactly as it should be. I had previously filed/cleaned the points and reset them. I also pulled the coils and tested them separate from the engine as I was doing the ignition overhaul and they were fine again.

Again, no joy. Same sputtery engine. At this point, I’m at a loss, but I think the only part I’ve not looked at was the wiring for the kill switch. I disconnected it, fired up the engine and its running beautifully…… AHA!

I removed the switch from the motor and took it in to the workbench. It had a rattle inside. I pulled off the rubber cover and the copper cone contact inside had broken free from the rubber part. It was effectively bouncing around inside the killswitch and periodically killing the motor for a tenth of a second here and there. Tilting the motor backwards made the cone fall backwards against the contacts and kill the motor worse. The motor would buck and the cone would jump off the contacts and she’d start running again. Lather, rinse, repeat, backfire!

To fix the issue, I drilled out the broken steel OMC rivet and put in a new aluminum rivet with the head protruding so it would grab in the recess in the rubber boot. Polished everything back up, pressed everything back together and a continuity check showed it worked well. Shake it hard and the cone is firmly mounted.

With the switch re-mounted in the motor, it runs beautifully, either position, full down trim, or full up trim. Idle is very clean (much cleaner than in the videos. It goes into gear at a very low idle speed and I believe would troll my boat along at a very low speed quite nicely.

Maybe someone will find this thread in a search and it will help them.