This is a 92 Wildcat 700 engine that I installed in my old 92 Polaris 500 SKS with rolled chaincase and 136" paddle track. Great sled, It worked perfectly for 3.5 years, but during the end of the last year we had snow (spring 2014) I noticed that during very long sustained WOT it acted like it was running out of gas. It is very responsive from idle and through midrange, and at first the WOT is perfect. But then under very long WOT pulls it acted like it was running out of gas. After waiting a moment to calm down, it would run again.
Now it can barely handle WOT for more than a couple of seconds before bogging down. So the problem has gotten a lot worse, but it still idles and works through midrange normally, very good and responsive power until it bogs out.
The clutches are good, fully inspected both. I have tried much richer and leaner main jets (the old ones did work perfectly for several years). I replaced all the fuel lines, filter, and tested the fuel cutoff - and there is no air bubbles in the fuel lines. I replaced the high performance fuel pump with a different high performance fuel pump (no effect). The impulse hose is solid. I don't see any leaks coming from the PTO seal (the impulse comes from PTO side) and the power is good before it bogs, so I don't know if that rules out bottom end compression or not. There are 2 impulse ports, the mag side one is capped - in my informal test of both impulse ports it "felt" like the mag side one was pushing harder. Again, I have just been using the PTO side impulse port the whole time it was running well. I also cleaned all of the electrical connectors and put in fresh dielectric grease.
So, honestly the lifespan of this sled is just about done, but I would love to fix it if I can. At this point I can't even be sure if the problem is electrical or fuel related. Does anyone have any thoughts?
When's the last time the springs in the clutches were replaced? Springs that have lost their tension may cause problems like that. If it's been more than 1000 miles since the last time they were replaced, I'd change 'em both and see if that helps performance.
2007 RMK 700, 2008 RMK 600, 1995 AC Prowler 2-up, 1980? AC Cheetah
Yeah I guess it could be the clutch since I have been on the same primary spring the entire time. I have switched the secondary between this one and my other 700 so I'm pretty confident that's not the problem. It seems pretty unlikely but then again you never know, a lot of engine problems are actually clutch problems. I have inspected the rollers and all the rebuild parts, they seem to be still serviceable, and it just seems to work too well until it bogs. But...if I ever touch this thing again now that I have the new summit, I will check that out.