I bought a used 2006 Sportsman 500 HO EFI and it is leaking oil into the recoil. I have had 2 different mechanics change the crank seal and the o-ring behind magneto, but it is still leaking oil onto the recoil rope. The last shop (a reputable dealer that I trust) checked the runout on the crank before changing seals, but it is still leaking oil. When I pulled out the recoil rope today to check for leakage, I could hear air pressure relieved from recoil. I checked the breather hose on case and it is not plugged. Any suggestions? I am stumped.

 

Check that the oil tank breather hose that goes to the air box is open. There will be a small split in the hose about 2 inches out from the oil tank nipple(for condensation to clear) that you may have to tape up to test or just use your finger. Should hear a rush of air in the air box when you put an air nozzle to the tank end of the hose. If they installed the seal right along with the two o-rings,it shouldn't be leaking as long as the crank case and tank vent are open.One other reason for this to happen is a stuck oil relief valve. Could be allowing oil to drain from the tank into the engine when it's at rest. The nut is below the engine oil lines. Behind it is a spring,washer and plunger. Pull the plunger out and clean it up.Make sure it slides back and forth easily in the engine. If not it might be the cause of excess case pressure and may need to be replaced.

 

Thanks for the suggestions. I will check it out and let you know. This is the first 4 stroke Polaris I have had, although I have a Yamaha as well. The oil system on the Sportsman is foreign to me. While engine is warm, right after running it, oil level is well over the safe range on dip stick. When machine is cold, level is perfect. From what I read online, this is how the system operates? Thanks again. I'll post back with my findings.

 

did you find the issue with the oil leaking into recoil?

 

Yes. As recommended by Old Polaris Tech, pulled the crankcase pressure oil relief valve plunger out and cleaned it along with the hole it sits in. Used a q-tip and a small wire. It didn't seem excessively dirty, but the hole that allows the oil pressure to reach the plunger may have had some gunk in it.