They've always been plastic even back to the w/c 350 2 stroke. Out of all the years I've messed with em,I've only had about 3 or so Polaris atv impellers do this.I've actually had more PWC stainless steel impellers that sucked air into the pump housing do this than the atvs.Some even looked like holes were cut into em with a torch by the heat from cavitation! This trapped air gets super hot! The plastic impellers will last for the life of the atv as long as you keep the air purged from the system and it doesn't get too hot. OPT

 

So finally got in a long ride today fourwheeler has been doing great. Took it out twenty minutes in it said hot engine so I shut it down and fan wasn't starting. I always keep scrap wire and quickly jumped the fan to get it to run. Kept going along with fan continuously running and another half hour or so I stopped and in started idling bad and acting the same again. I gave it a quick break tried connecting the harness back up to the fan but nothing changed. I rehooked my jumper to keep my engine cool and rode back to the truck it shut off a few times but sometimes it would run good for 5 to ten minutes at a time. It would just start acting crappy when I let it idle for a minutes.
Strange that it runs good for awhile and then just acts crazy. I'm figuring the fan not coming on may have something to do with it because it was kicking on just fine a few days ago. Just got to figure out which wires are bad or something.

 

There are two relays under the front panel the left one(facing the front of the atv) is general power and the right one is the fan relay. There should be a 20 amp circuit breaker that ties into the fan relay red wire that can corrode and cause intermittent or no power to the fan relay causing the fan to short cycle or not turn on at all. It's either taped to the harness or it's in a sealed plastic pouch. Cut the pouch open and check for any corrosion on the terminals. The breakers can still get moisture in the pouches and mess things up. One recent poster had the same problem on the fan short cycling and over heating and found the circuit breaker was the problem. Plus you could still have another problem when it comes to idling.Still could have a wiring issue on the tbap sensor harness as a lot of people have experienced. Are you throwing any codes at all in the speedo besides the hot light?

 

OK I'll check that out but even after I wired the fan in so it would just stay on it cooled down and stayed cool and it started running bad awhile after that.

 

This could be because of the possible short in the t bap or tps sensor harness wiring. Still sounds like you have two problems. A circuit breaker not allowing the relay to operate the fan causing it to run hot and then the most common problem on the efi machines,the thin sensor harness wiring that can break internally or have a bare wire grounding out causing them to run crappy. Only The Best

 

I'm gonna go ahead and order that harness and I'll check the fans as soon as the wind dies down.

 

So I tried again replaced the t bap harness checked everything and it ran great for an hour or so again. Than once it flashed hot engine and went back off a few seconds later. After another ten minutes it did it again flashed hot engine at me and stayed on. I once again jumped the fan just to make sure I didn't overheat even though it didn't feel excessively hot at all. Shortly after that it started running bad again. Bogging down cutting out no power except higher rpms. Lower rpms it will shut off than I restart it and it will run good long enough for me to get the rpms up and go for a bit. I brought a gas jug with me and topped off my tank to make sure something was good there and no difference. I even unplugged my temp sensor for a bit on the way back and all it did was throw a code. Once home I even yanked my thermostat out and rebled the system to make sure it wasn't running bad because of heat. New water pump still pumping great and it is just running bad after an hour or so every time. Not getting any better.

 

Did you ever find and replace the 20 amp circuit breaker that sends power to the fan relay? I have had this problem also ,especially if the fan is short cycling because of the thermal circuit breaker getting hot and tripping. Once it cools down they will send power to the relay again. If you're positive the harness kit has a good connection and all the air is purged and the radiator is clean.

 

ya I've purged radiator twice and done it a million times on vehicles. The harness is good I'm pretty good at wiring I've been working on cars for roughly 14 years. I did swap circuit breakers you were talking about while I was having issues out on the trail and it had no apparent affect. But even when I jump the fan to cool it off it still runs bad. Strangely after I yanked the thermostat out of the system and repurged it ran bad. I let it sit for about ten minutes while I was on the computer doing research and I went out and rode it for about 20 minutes fan was kicking on fine running great. Maybe I'll take it for a cruise again tomorrow. The circuit breakers you were talking about were the big square ones side by side right?

 

NO,these are relays! Both relays are the same(doesn't hurt to switch around) The one on the left facing the atv is the main power relay,the right one is the fan relay. The fan relay gets it's power from the circuit breaker on up the harness. It will either be in a sealed plastic pouch or will just be a silver module taped to the harness.I've found them this way also.Look at this breakdown(not sure on your year model) at the harness description. There are several item #1's. Find the 20 amp circuit breaker on the break down.Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
It will look like this.New Polaris 20 Amp Circuit Breaker Magnum Predator Sportsman 700 2410323 E4 Po | eBay OR this.Polaris New ATV Circuit Breaker Kit 20 Amp Ranger Sportsman Scrambler Magnum | eBay