First of all, thanks OPT for all of your help when I started working on this atv for my daughter.


I have the ATV running but there are minor issues and I am not sure what is going on.


When I have the air box removed the only way it will idle is with the idle screw all the way in. I was thinking that I have air entering beyond the carb, maybe the boot...


However, I can choke the engine with the choke or by covering the air intake and the engine dies. Remember, it runs like a scalded dog without the air box. I know I can't do this forever...


When I install the air box without the filter or air box cover, the engine will not run at idle and doesn't want to run under any amount of throttle. It seems really strange that just by connecting the box to the carb that it would restrict the airflow so much that it won't run.


All thoughts and suggestions are welcome.


Thanks,
Kevin
Polaris Tech In The Making

 

Did you ever get a carb kit? Last I read you'd pulled the carb off several times cleaning it.https://www.ebay.com/itm/Shindy-Carb...xVQazv&vxp=mtr That may solve the problem if it's running too rich because of a worn needle and seat.It needs an air box and filter to correctly do any adjustments.Did you get a new or used one to replace the cracked air box?On these old carbs usually 1-2 turns out on the air screw is good enough.Should idle good if everything else is ok. Plus spray some WD40 or contact cleaner around the intake manifold,cylinder base gasket. If the engine idle changes,you have an air leak. Plus on a model this old,the crank seals are almost a given thing to change right off to bat.Between the possible carb being too rich on fuel and possible seals leaking it would be almost impossible to adjust the carb right.https://www.ebay.com/itm/Polaris-Tra...BZ25XV&vxp=mtr Plus I can't remember off hand but what was compression reading?

 

To repeat what OPT stated - engines and carburetors are matched and engineered to run with an airbox.
There is a specific airflow carburetors need to function correctly, and the oem airbox is designed to provide the right amount of air and turbulence to pull fuel into engine.

​​​Plan to rebuild the carb with a quality rebuild kit - cheap ones will not have the correct jets and cause further problems than an extra $10-25 for a well reviewed kit.

Hope this helps!

 

Thanks OPT! I suppose I still have a little work to do. I'll start by borrowing a comp tester from Autozone.


How difficult would you rate the crank seals?


Thanks,
Kevin
Polaris Tech In The making...

 

Have to have a puller for the drive clutch to get to one seal. Or you can make one. a harmonic balancer puller or heavy duty steering wheel puller to pull the flywheel.You can rent these at most auto stores.Mark the stator plate before you remove it. Crank seal is behind it.