Paranoid Carb Cleaning Question

[paul407]

Can someone tell me what they think is wrong with my wife’s ATV. Just cleaned the carb for the winter riding because it was running like crap (also did the air filter, spark plug, oil, etc.).

Now the quad accelerates and does everything else perfectly. However, if it is idling in Neutral and I mash on the throttle, the quad will bog and die. I tore the whole carb apart again and check the needles and everything but can’t find the problem. The reality of it is my wife will never have the need to mash the throttle unless she wants to end up on her back with the quad on top of her. I thought it might be from the old gas but got rid of that also.

Brendan

 

[biglou]

Four stroke? If the carb has an accellerator pump, like the bikes do, it shoots a stream of gas down the intake tract to give an off-idle kick. There are homemade mods to the bikes' carb, Kehein FCR, to make a user-adjustable timing screw for the squirt duration. I know nothing of quads, so there may be an adjustment on yours? If it doesn't have the accel pump, I'd suspect need of adjusting the pilot screw or changing the pilot circuit jetting.

 

[paul407]

Sorry about that.

The quad is a four stroke and a 2002 warrior (350). I have to assumet that a four stroke is a four stroke. Nothing has changed on the bike except for the fact that it ran poorly about four months ago and I just cleaned the carb and full tune up. Is the pilot screw the same screw used for adjusting the idle?

 

[biglou]

Nope. There will be an idle adjust, and also a "pilot" screw which will adjust the mixture at no-to-low throttle settings. It can have a pretty dramatic effect on off-idle throttle response. On the FCR carbs, it's in a hole at the front center of the float bowl. Screw head facing down. Can be tricky to get at. If you can figure out where yours is, run it all the way in (and just for grins, count how many turns that took so you'll know if it was way out of adjustment), then back it out 1-1/2 turns. See if that helps the bog. If not, go back in to 1 turn out and try again. If it's still bogging, go to the next size smaller pilot jet and start over at 1-1/2 out.

One note here-a lot of times you'll get that bog if you whack the throttle full open when in neutral with no load on the motor, but while moving, it's not an issue. See how it performs while riding. You may have to strike a happy medium between the two.

 

[paul407]

Thanks. Will give it a once over with my new found knowledge.

Brendan