Hi, I have a 1964, 3.5 hp, model MLM 6904B wizard. Starts and runs fine, but smoke (sometimes heavy) comes from the middle unit especially from the lower water intake hole and when the engine is shutdown from the water exit hole. The slower it runs the worse the problem. The smoke doesn't feel wet like steam. The middle unit does warm up when running but not too hot to the touch. I've changed the gear oil, and put a new gasket on the lower unit cover plate opposite the propeller. The powerhead doesn't smoke and the water pump puts out a pretty good stream of water. I'm confused. Can anyone help? Thanks

what mix are you running? are you running it in a barrel? They seem to smoke more in a barrel, but actually no. It's just that the smoke had no where to go. I usually run a fan on them when running them as the carb will sometimes eat the smoke. also synthetic oil will smoke less.