Carburetor Adjustments

[whorton12]

Hey first time posting, but i am having trouble. Recently bought a 1953 Cub for mowing my 8 acre property. The engine is revving up and down a little when it idles, but when I am running at full throttle the power keeps dropping down periodically. I think it has something to do with the little screw on the carburetor, but i cant find anywhere to show me the proper way to adjust it. Any help would be great.

Thanks so much,

[Glen]

Hi,
Here is a page from a Cub owner's manual telling how to adjust the idle screw. This is the IH carburetor. Click on the pic makes it bigger.

http://www.cleancomputes.com/Cub/Cub%20 ... age-22.jpg

[Eugene]

1 1/2 turns out. If this is the IH carb, the screw is for an air bleed and not fuel.

Throttle linkage adjustment from governor arm to carburetor. Been discussed many times. Search function top of page.

[dgrapes59]

Welcome to the Forum!

Good luck with the adjustments,

[whorton12]

Thanks for the replies. Played with it some more today, I think the problem is more than the air adjustment. I think i need to rebuild the carburetor. I took off and cleaned the fuel reservoir bowl and the fuel filter and cleaned the main jet. Still no change. i think maybe the float inside may be bad. Hopefully will try to do that tomorrow or Wednesday. If anyone has some links showing this done in detail that wouldn't hurt.

Thanks,

[Scrivet]

My opinion is figure out what is happening before willy nilly trying things and throwing parts at it. First give the carb a good cleaning. Make sure it actually needs rebuilding before you do, it's running now so I doubt that it does. You mention fuel filter, if this is an add on and not for a gravity flow system that very well could be causing problems. The sediment bowl under the gas tank should have a screen in the top of it for the big floaters. The heavier stuff will settle to the bottom of the glass bowl (Sediment bowl). There also should be a screen on the inlet of the carb. These two together do a pretty darn good job of catching crud, don't really need the fuel filter.

For the reving up and down make sure the carb linkage to the govenor is adjusted corectly and there is NO independent movement between the cross shaft and arm with the throttle spring behind the fan.

Welcome to the forum by the way.

[randallc]

Welcome to the forum from Arkansas. If you are new with Cubs, the best time that can be spent is researching this forum. Check out the manuals at the top of the page. Check out the frequent ask questions and cub book of knowledge. It is a great help.

[pickerandsinger]

Sounds like the governor to me especially if it does it regularly….Its easy enough to adjust..Read the post about throttle by regarrr and Barn Yard covers it in his reply…Welcome to the Forum….Dave