I looked every day for about 8 months before I finally found a late 90s M40C short shaft, tiller, no electric start or charging. I wanted the lightest (129 pounds!) 40hp I could get for my 14 foot inflatable. Well this has been a total failure for me, the "short" shaft does not fit my transom; it's about three inches too long, I can?t get the motor high enough :facepalm: I should have just bought a long shaft if I'm going to have to buy a mini jack-plate anyway, they're easier to find and easier to resell. So anyway, I put the motor on the inflatable shimmed up as much as I felt was safe, and it has allot of power and runs good except for a slight chug at idle and white smoke at idle only, the smoke is thick and looks like dry ice smoke, just floating there when the boats not moving. When powered past idle the engine runs normally without any unusual smoke, and it never seems like it wants to die while running. I got some Sea foam and idled the boat at the dock for about 1.5 hours, I figured since the problem is only at idle I wanted the Sea foam ran through the carb?s pilot circuit. It dint do anything, so maybe this is a cooling issue? Also the motor is too powerful for the inflatable and I?m not going to use it, the floor flexes like crazy when you throttle up and going 30+, the inflatable is rated for a 40 but I think it should only have a 25. So I?d like to sell the motor but only if it?s working properly, I won?t sell a motor with something wrong to someone ells. I know white smoke is usually steam, I put a new impellor in as soon as I got it and it seems to be pumping properly, the telltale looks good. One other thing, after running past idle it takes about a minute for the white smoke/steam to come back, it only does it when idling for a little while. Thank you in advance for your replies.
