Reply To: Something a little newer

[David Stanton]

I have five of these 15s with mega-hours on them from a failed resort, ranging from the late 1970s to 1991. I have the newest three running great (1989-1991), and have gotten the older two to start. Sometime in the late 1980s, tuned exhaust was added to get the output up to 15 HP measured at the propshaft to compete with the foreign brands – not sure what year it was added, but my 1989 has it, and I can tell from the photo that your 1986 does not. The only difference between the 15s and the 9.9s is the carb. I fixed a 9.9 for a neighbor that wouldn’t idle right no matter what i did, and switching to NGK spark plugs magically cured that. I have not seen that problem with any of my 15s. Not sure what year they went to throttle cables from the tiller, instead of the traditional rod/rear mechanical tiller that was known to wear out on these models with a lot of use. The only thing I’ve found that is a bit dicey to remove and repair is the recoil starter assembly – if you take it off for any reason, have a nut ready to put on the bottom of the long mounting bolt to hold the whole thing together – if I remember right, it’s a 3/8-16. I found the SIerra impellers , even with a new Sierra housing, don’t cool at slow idle, but OEM impellers work fine. Electric start is rare on these. For $100, I’d grab it!
Dave