Scottie, No real answers but just chucking some thoughts at you.
I too have had the slipping coupling effect but if yours speeds up and slows down as if the trottle is being opened and closed very quickly it seems more like an electrical effect.
If you can run the boat past yourself on the bank with the superstructure removed and see if it is one or both of the motors that are affected then it would help to narrow it down. Obviously if only one then you would be looking at that side only but if both then something common such as the receiver would be a possibility. Maybe put it in the bath and run it in the same way to see if you can identify which one. Another possibility would be to disconnect one side at a time and see if it persists with one or the other.
If only one side then I would suspect the speed controller but bear in mind Adz's purely mechanical suggestions. If it doesn't happen on the bench then it is load related and a slipping coupling is still a possibility.
If you are convinced it is both sides then you have to look at the receiver and its power supply. If you have already changed that and the problem persists then it is possibly only happening on one side.
Anyway, as I said just, some thoughts out loud that may be of some use. Let us know how it goes. |