I bought a 98 xplorer 300 4x4. the guy I got it from said it wouldn't idle low so he had used the throttle cable adjuster at the handlebars to bring it up which was pulling on the oil pump cable too. I drained most of the old gas, cleaned the fuel filter, cleaned the carb out and put fresh fuel with a touch of seafoam in it. it still wouldn't idle down enough so I started playing with the mixture screw. best spot I could get it to run at was 1/2 a turn out (the dealer said I should start at 1.5 turns out) and I could get it to stay running on the actual throttle stop on the carb. still was high and didn't want to go into gear. I moved the needle up and down and that didn't help. I took it for a good run yesterday anyway (I didn't really see any smoke out the back since the o/p wasn't being pulled on at idle anymore, im not sure how much oil that pump puts in and how much smoke there should be) and when I got back it was idling high. so I turned the mixture screw out to 1.5 and lowered idle as much as I could (which still seems high). still doesn't want to go into gear from neutral. do I need to adjust the shift linkage?

also it is fairly hard starting. I have to put the choke on as much as it will and pump throttle while cranking. probably taking 15-20 seconds. is the coke out of adjustment or is it related to my high idle problem? I also noticed one of the fuel lines on the bottom of the tank was seeping gas. and I do see sediment in the tank, so probably going to pull it off and clean it out.

anybody else got any other ideas or tricks/tips for these units?

 

Take a compression reading first. If 120 or below,this could be the main problem,plus leaking crank seals,leaking intake manifold,or base gasket can do the same thing. Having to adjust the throttle cable to keep it running and shutting down the air/fuel screw,plus hard starting is usually an indication.

 

ok, thanks. I was thinking maybe crank seal or gasket. I did notice some oil on the skid plate and haven't found where it came from yet so probably a seal or gasket. I have the intake off and it looked ok. I didn't see any cracks. I even put a little rtv around the o-ring to make sure it would seal.

I haven't checked compression yet. I was actually planning on getting a gasket and seal kit anyway, as well as a wiseco piston since I have been reading about the skirt on the exhaust breaking.

how are these things on chains? I'd rather not have to replace 3 chains all the time. mine look ok and I adjusted all of them. I did notice some sprockets starting to show wear though.

 

Check compression,if it's low you need to have the cylinder measured as the over size piston needed and have the cylinder bored. Just my again, a top end only on a 15 year old machine may not hold up..Just keep the chains lubed and adjusted and see how it does after you get it running properly.

 

I ran the compression. 95psi is all I got, so I guess I have to take it apart.

 

Save up your money if you have to and do it right. Rebuild the engine and not just a top end!!

 

wise words from OPT

 

Do you mean replace the crank and/or con rod too? Or just bearings, seals and gaskets?

 

Rod kit that comes with lower rod bearing,spacers and new crank pin. The three(3) crank bearing you can get from any parts or bearing house by using the "universal" number on the bearings. Plus new crank seals. Rod kit needs to be installed by a dealer or machine shop unless you have the equipment.(press,truing stand,dial indicator) Then you need to have the cylinder measured and order the over size piston needed and have it bored and honed. Wiseco is most people's choice on piston kits. Polaris 300 Xplorer 4x4 1996 1997 1998 1999 Connecting Rod Kit New | eBay

 

I ordered a rod, full gasket set and seal set. took it apart today and found that one side of the piston was rubbing the cyl. my rod should be in tomorrow so hopefully I can get my cyl and crank dropped of to be done. my friends uncle owns a atv/bike/sled shop so i'm having them bore/hone cyl, put new rod on and fit the piston.