Re: Carb Adjustment Farmall 400

Posted by Bob M on March 16, 2003 at 07:21:43 from (66.66.123.133):

In Reply to: Carb Adjustment Farmall 400 posted by Scott(TN) on March 16, 2003 at 06:22:11:

Scott - A couple easy things to try first: Remove the air inlet hose at the carb. Make sure the choke opens all the way when the knob is pushed in - adjust the cable if it does not. Now run the motor with the air hose off. If it runs better, the air cleaner is plugged and should be cleaned.

If that doesn't help, run the bottom carb adjusting screw (high speed adjustment) in all the way. Then back it out 1 turn and try the motor again. If this helps, adjust this screw in or out as required for best running at full throttle.

The upper screw is the idle mixture adjustment. If turning it in/out has no effect on idle speed/smoothness, it means the carb idle circuit is plugged. Only fix is to remove, disassemble and thoroughly clean the carburetor.

Finally another possibility is the cam drive gear key has sheared. This causes valve timing to drift resulting in loss of power and black exhaust. It may cause the spark timing to jump around as you observed. It may also be accompanied by a knocking sound from the front end of the motor when idling. And if you remove the hydraulic pump you may sometimes (but not always) find the cam gear inside can be moved a bit under finger pressure. The only solution is to remove the tractor front end, timing cover and cam gear, then installing a new key. Not a difficult job but requires removing large/heavy parts to get to it. (Note: This seems to be a common problem with 4 cylinder Farmalls with live hydraulics - it's happened to my Super M, also to a buddy's SMTA and 400.)

Good luck!!

Follow Ups:

• Re: Re: Carb Adjustment Farmall 400 Scott(TN) 08:38:37 03/16/03 (0)

Post A Followup Name: E-Mail: Subject: Re: Re: Carb Adjustment Farmall 400 Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]