Got a 550 that runs fine until cranks to top speed while wide open for about 100 feet. Then cuts out like a limiter. No backfire, just starts to stutter while at full bar throttle.
Any suggestions would be great. Runs great until pegged to handlebar. Thanks
I looked through the Polaris parts diagrams and couldn't find a detonation sensor, or a throttle position sensor, so it doesn't look like that would be your issue.
If you had some kind of restriction in the intake or exhaust, it would not be able to get to full rpm at all, but yours runs ok for 100 feet...
Are you getting adequate fuel delivery to the carbs? Sometimes a fuel pump is failing and you get enough fuel for mid-range operation, but when the demand exceeds the supply, the engine falls on its' face.
Along those lines, are the vent lines to the fuel tank clear? If you're pulling a vacuum on the tank, the same thing could happen. That would be easy to test; next time, crack the fuel tank cap a bit and if the problem is resolved, check the fuel tank vent line for an obstruction.
Rule out fuel pressure and a vacuum on the tank and that leads to electrical. How is the spark? How new are the plugs? How is the connection from the plug wire to the plug? You can unscrew the plug boots and snip off about 1/4" of wire and screw them back on to make a new contact just to rule out the connections. Then it's on to the electrical system... a failing coil or stator may cause issues like you describe. You can test the coil and stator, but you will need the specs to do that. A repair manual should have them...
Checked the vents on the carbs, and was tracing down the vent for the fuel, and noticed one of the wires that goes to the coil was out of its holding mount. The wire was hanging just enough that it was rubbing every now and then on the secondary clutch! Spliced the wire, and good as new.
Awesome! Thanks for posting back with your fix, that can help someone else with a similar problem!
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