Hey everyone, I'm new to the boards and I'm looking for help with my new toy. Bought a 98 TB 250. All I knew about this Quad was the previous owner ran it through med and water and it didn't run again. I knew I would have to rebuild top end. That has been done but I'm still having trouble getting it to run. It has spark and turns over, but won't run. We noticed gas in the exhaust so we pulled carb and cleaned it. After we reinstalled carb we have the same issue.... gas in the exhaust.

BTW, thanks for all the help these boards have been up to this point... it's been my go to for most all issues!!

Steph

 

Install a carb kit with a new needle and seat instead of just trying to clean a carb. Make sure the float arm is parallel with the carb body when the carb is held upside down.Pull the spark plug,hold the throttle wide open and use the recoil starter to try to clear the crank case of excess gas. Or you can pull the 10mm crank case drain plug.If none of this helps then I'd replace the crank seals starting with the major one that leaks,the one behind the drive clutch.If it doesn't have good lower end compression(crank seals) with that new top end it can't atomize the fuel/air mixture properly and just fouls plugs or you end up with a crank case or exhaust pipe full of gas. http://www.ebay.com/itm/Carb-Rebuild...NThNZT&vxp=mtr

 

We've rebuilt carb and still have the same issue. Looks like we will be replacing seals now. crank case was full of gas, drained it two different times and it filled right back up.. Most likely a bad seal? Is it best to pull motor and split the case? Or can it be done while bolted it? Any advise would be very helpful.

 

If you're sure the float is adjusted right,not dumping a load of fuel into the engine,then yes gas can accumulate in the crank case if the seals are bad because it can't compress up the transfer ports. You don't have to pull the engine,but do have to pull the drive clutch to get to the seal that most often fails. You need a puller.Either buy one or get a bolt from a hard ware store and make your own. 3/4 x 16 pitch threads.

 

Removed the drive clutch last night without any trouble. (Thanks for the tip on the bolt size needed to complete)

I'm a bit worried. There is a lot of play in the crank. It can easily be wiggled. Should I just bite the bullet and rebuild the whole bottom end?

 

Rebuild it! Should be NO play in the crank shaft..Probably why the seal is leaking. After tear down make sure the rod doesn't have any up and down play on the crank shaft or a new rod kit will be needed also.

 

Thanks!! I figured that was best. Rod has a lot of play side to side so will plan on a kit as well. May as well do it right.

 

Do they make a bottom end rebuild, or do I have to buy piece by piece?

Checked some sites, but no luck with kits.

 

Side to side play is ok on the rod,but NO up and down play allowed. If the rod needs to be replaced you can get it on ebay along with the crank bearings and seals,but are separate.Polaris Trail Boss 250 1987 1999 Connecting Rod Kit 3082790 | eBay 1999 2006 Polaris Trail Blazer 250 Main Crank Crankshaft Bearings Seals Kit | eBay

 

Thanks for the links and advise... by the way.. fellow N. Texas here.
I'm in Burleson, South of FW.