Hi all,

I picked up a 1990 square nose last year from a guy I knows sister who bought it new for $300. Hasn't been ran in a few years.

Took the engine hood off and mold on the entire engine. Everything inside was gross. He said his sister used to race it. Looked stock on the outside minus air intake. I pulled the engine, cleaned hull and fuel take all out spotless. Next I took intake manifold off and saw a tiny bit of rust on one of the cams so I figured I better dig in. Turns out, all the cooling sleeves were completely oxidized and almost full of dust. So I cleaned everything, used a scotch bright to clean the small amount of rust off of the one cam. Everything felt very good and everything was in spec according to the service manual so I proceeded to re assembling. Had to buy a new OEM carburetor (Primer Kit version). Top end appeared to have recently been rebuilt so I checked specs and put it back together. Flywheel was completely corroded so I cleaned that up really good, also had to put a new stator in because of the corrosion. All new gaskets and seals obviously as well (there was no seal between upper and lower crank cases? odd). Everything was done step by step according to the service manual.

Went to start up and it fired right up immediately. Shut it down after 30 seconds. Checked compression and was at 146PSI in front and 145PSI in rear. Used garden hose and started it up and it idled completely normal. However, the problem I am having is I have a knocking in the engine that only makes noise when engine is revved up anywhere past idle. Ran for 15 minutes then shut down. Top end and exhaust never got over 50 degrees F (ground is still cold here in MI), front of bottom end was at 100 degrees F and rear of bottom end was at 90 degrees F.

Was curious if those temps are normal. I have never checked it on my 2016 SJ and it is still in storage. Also my new ski does not have the knock obviously.

Any help would be great......

Also If you email me I can send you the video of what it sounds like because I do not know how to attach videos.