I bought a 94 GTX (657) last year that was in "Like New" condition but was sitting for some time. It ran great for about an hour then kept shutting off. After further inspection we determined the rear (PTO) cylinder and piston were toast and this was due to what I believed to be a lean running condition from the internal carb filter being almost completely clogged. Since then here is what was done to the ski.
New (PTO) cylinder and piston
Rebuilt Carbs with OEM Mikuni carb kits
Replaced all old grey fuel and vent lines
Cleaned fuel filter basket
Last week I took it out to the lake and the thing ran great for about 1/2 then kept shutting off again. This time the the front (Mag) cylinder was the issue. The plug was dry and had melted aluminum covering the electrode and the piston was burnt almost the whole way thru right in the center under the plug.
After some reading I am realizing that this hole in piston was caused by "Detonation"
Going by the history I just described and the work I have done to it what would be the first thing I want to check before replacing the piston and running the ski again.
One of the causes I am reading says bad/old fuel. The fuel has been in it since last July but fuel stabilizer was added in the fall. Can fuel go that bad that fast possibly causing this?
Thanks!
New (PTO) cylinder and piston
Rebuilt Carbs with OEM Mikuni carb kits
Replaced all old grey fuel and vent lines
Cleaned fuel filter basket
Last week I took it out to the lake and the thing ran great for about 1/2 then kept shutting off again. This time the the front (Mag) cylinder was the issue. The plug was dry and had melted aluminum covering the electrode and the piston was burnt almost the whole way thru right in the center under the plug.
After some reading I am realizing that this hole in piston was caused by "Detonation"
Going by the history I just described and the work I have done to it what would be the first thing I want to check before replacing the piston and running the ski again.
One of the causes I am reading says bad/old fuel. The fuel has been in it since last July but fuel stabilizer was added in the fall. Can fuel go that bad that fast possibly causing this?
Thanks!
