Hey, just registered here, been lurking awhile, found this site while looking for info. Have found alot of good stuff with the search, but need some help.

I picked up a 98 Express 300 2 stroke for just a few bucks. It was non running. I pulled the jug and piston/rings were shot. Bored the jug, installed new wiesco piston and rings etc. Got it running and it runs, but I seem to have carb problems. I took the carb apart and cleaned it all up good, but I have no idea how to set the float level or what to set it at. Also, there is a thumb screw on the side, and a small brass screw at an angle on the side of the carb, can anyone explain what these do? In a nutshell, I need a carb 101 class to help me get this thing straightened out.


The starter also grinds pretty badly when starting, and seems to make some noise while its running, Im assuming its the starter drive? I havent dug into that yet, trying to get my carb issues straight first, any thoughts on this?


Any info would be greatly appreciated. I work on Cadillac's for a living so im perfectly mechanical, I just have no experience on these small engines, let alont 2 strokes. Thanks,

Scott

 

Scott: Did you remove and clean the pilot jet? It's in the smaller "tube" right alongside the main jet. The float setting s/b close if you use about 1" above the float bowl gasket surface (hold the carb upside down and measure up 1" to the "bottom" of the float) The thumb screw s/b your idle adjustment - screw it in to increase the idle - the brass screw at an angle s/b the air screw - gently screw it in until it stops, then back it out 1 1/2 turns s/b close.

 

Greatly appreciate the reply. Yes I did remove the pilot jet. tonight Im gonna take it back apart and soak it all night, yesterday I just used carb cleaner and air. guess I will just have to "play" with it a little until its running better. I only have a few dollars in the bike and I know its not worth alot so I dont want to pay anyone to work on it. I guess some time and patience are in order lol


Scott

 

Well I let the carb soak all afternoon and evening. Come to find out I had the brass horseshoe looking thing in upside down. It runs a hundred times better but still far from great. Atleast now the idle and air screws are working and the carb responds to adjusting them.

I cant seem to get it to idle low enough for my liking. If I let it idle for a min or two it dies out. I have to choke it to get it started even once everything is warmed up.

I also cannot get it to shift into high range, it just grinds awful. If I shut it off and put it in gear then start it it works fine. I adjusted some on the linkage but didnt help much.

One other problem, there are two oil lines coming out of the crank case, one that feeds it and the other looks like a vent hose. I have oil coming out of the vent hose, not alot but enough to make everything nasty.


Anyone shed any light on any of my concerns? Forgive my ignorance, I am all new to these things. Thanks,

Scott

 

well the vent hose coming out of the crankcase. IS actually coming out of the counterbalencer area. Do an oil change on the that part and see what you get. you should have about 75-100 cc of fourstoke oil in there. The water pump is located in there as well. So if the water pump seals are leaking, water can get in the and rust the bearings. The bottom of the case has three drain holes. one in the crankcase itself, one in the recoil starter area. and another in the counterbalancer it is the middle one(not on an angle)
Yes the stater drive must be seized up. it doesn't want to go out all the way and it must not be retracting properly. they are really expensive from polaris. But brand new aftermarket ones are all over ebay. about 100 usd with a stater. polaris wants 225 cad for just the drive.

with the tranmission, check to see if there is play in the tie rods on the shifter linkage.

 

300 polarises are air cooled and no counter balance.

 

Yeah its air cooled so no w/p I have no idea aobut weather or not it has a counterbalance shaft. So where is the fill plug for the crankcase? Does it have a dipstick or does it need to be filled with a certain amount of fluid? The oil leaking out of the vent is two stroke oil for sure.

As for the shifter "ball joints", they are tight. One was worn badly where it bolts to the arm out of the trans so I took it off, drilled the hole out larger and put a sleeve in it so it all fits nice and snug and has no slop. Maybe its because its idling a little high? No idea what its idleing at but would guess 1500rpm maybe.

 

it's a 2 stroke engine. no oil in the crank case like a 4 stroke. the oil is injected into the enigne via the oil tank in forn of the bike which takes 2 stroke oil.

 

gotcha. So what could be making it come out the vent? Comes out prettyy good.

 

There should be an oil pump below the carb, one line comes in from the tank, and the other goes out to the spigot under the intake boot. If it is like the 250. Doc