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Replacing A PERC Engine With A Non PERC Motor

Perc Kit

My good friend Dave recently had his Polaris 800 snowmobile engine give out and with a little searching we found a non PERC 800 motor to replace it with, here's what you need to know.

Yes, you can make it work but there are some things you need to know and you have options. Polaris stopped producing engines with PERC capability a few years ago and more recently stopped selling PERC kits to make the swap with. As you probably know the non-perc motor's oil pump cannot pump oil in reverse and the flywheel timing is different which presents some challenges. Also, the recoil dawgs are designed to run in reverse on a PERC equipped engine but not on later models.

re-use the PERC flywheel, oil pump and recoil cogs. When you swap your PERC engine with some non-perc parts, or you're just replacing the crank case and top end, you need to retain all three of these parts assemblies. While it would be possible to NOT use these parts if you planned on never using the reverse gear you may run into some problems if, for example, the cord is pulled with the engine in reverse while at idle.

Tip: If you're planning on making this swap yourself, which will likely become more common as older engines wear out, take advantage of the rebuild time to swap out the aluminum VES guillotines with stainless steel parts, Polaris stopped making Aluminum versions in 2005. A titanium option was offered in 2004 but the stainless variety proved more durable.