I parked my 60 in 95 and finally got it back on the road this year. when I parked it, the motor ran strong, I think it was even a fresh rebuild. Before starting it up, I poured in some marvel mystery oil to let it sit for a few days. I this this and turned the motor over, with out starting it.

so after a tune up and a new carb, it runs fine and strong, but smokes like a mother on the high way. not sure if it is the MM oil burning out, the rings for sitting for too many years, or what. any thoughts? I am considering just pulling it apart and re-ringing it.

another question, are 40 hp motors the same width as 1600? I was wondering if I could put an aftermarket exhaust on it. The one I have lost a section of slip together tubing years ago and I have some ghetto exhaust bend-a-flex tubing on there now.

Marval Mystery oil is what I use for air tools. Maybe it's just burning that stuff out

your rings may be bad, or cylinders, hard to say. Could also be valve guides

40 horse take a different ex than a 1300 and up

Empi might still be making a dual exhaust for a 40 horse ? I purchased one about a little over a year ago from Old Speed in California he had a few. If you need 40 horse parts hit me up as I have quite a bit of 40 horse's.

i was driving it around last night, it only smokes after I have been on the highway for 5 minutes or so. dosn't do it in around town driving. guess I will just put some miles on it and see what happens.

still think I might put a cam, a re-ring, and some dual Kadrons on it though.

Kadrons will not work with a 40hp.Your would have to run at least 1300 heads and rejet the hell out of the carbs. That just my 2cents. Your better off buying a set of Riechart dual carbs that where designed for the forty horse's.