8N carb issues

[Brian Jasper co. Ia]

This Marvel Schebler carb has me stumped. The story is this tractor has a new reman engine from nnalert, somewhere in the past it had a replacement manifold on it. I had the manifold surfaced both carb and block sides before installing on new engine. Carb was rusty on the outside so I glass beaded it, opened it up and put a kit in it. The throttle shaft is tight and seal in place.
No matter what I do, it runs lean. Pulling the choke out part way and it smoothes right out.

 

[elmersooner]

I would pull it off and clean religiously---sounds like one of the passageways are clogged..you can check for leaks with spraying wd at throttle shaft, and gasket areas---but makes a heck of a mess.

 

[Brian Jasper co. Ia]

It is clean. Both halves look like new castings. I used compressed air through all passages and spray cleaner to verify they're open.

 

[GB in MT.]

[b:35b65c340f][i:35b65c340f]
Brian;
What is the TSX # of the carb...If it is a 241 or 241A, there may be no econo, jet in it, or it may be that, there is a passage plug-up problem. Have you for sure, ruled out a weak spark problem?????
Having to use the choke is sometimes, weak sparkies!!!!.....in fact MOST of the time!!!
Check spark....then use this pic. to wire out all the passages:
Pic. ......compliments of JMOR

If after all that, you are still havin' problems, shoot me an email, and I'll try to help ya!!!
Email open on the modern side at the bottom of this reply.

Gary [/i:35b65c340f][/b:35b65c340f]

 

[old]

Air and carb cleaner do not always tell the truth as for a passage being open. BTDT man times and as Gary knows it is easy to miss that one little piece of dirt/rust and that is all it takes to make one not work as it should. You need to use a small piece of wire or a torch tip cleaner tool to make 100% sure it is clean.

 

[Brian Jasper co. Ia]

(quoted from post at 23:17:58 07/24/11) [b:7b08997df3][i:7b08997df3]
Brian;
What is the TSX # of the carb...If it is a 241 or 241A, there may be no econo, jet in it, or it may be that, there is a passage plug-up problem. Have you for sure, ruled out a weak spark problem?????
Having to use the choke is sometimes, weak sparkies!!!!.....in fact MOST of the time!!!
Check spark....then use this pic. to wire out all the passages:
Pic. ......compliments of JMOR

If after all that, you are still havin' problems, shoot me an email, and I'll try to help ya!!!
Email open on the modern side at the bottom of this reply.

Gary [/i:7b08997df3][/b:7b08997df3]

efinitely not lacking spark. It has enough oomph to make 1 inch sparks.

 

[Jerry/MT]

IF in fact your carb is clean AND you have the correct jets in the carb AND you have the requisite FAT, BLUISH-WHITE SPARK, the color of lightning, AND you are running lean, you most likely have an air leak around around the carb metering section. Make sure your manifold doesn"t have any cracks or rust holes and that the manifold and carb gaskets are not leaking. I know you said you surfaced the manifold but the block may not be truly flat.