Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Discussion Forum
:

Backfiring B

Welcome Guest, Log in or Register
Author 
Green_in_MI

07-16-2002 20:17:31




Report to Moderator

My 49 B was never easy to start but now all I get is an occasional backfire when cranking. I have put in new condensor, points, wires, and plugs. The plugs now get a good spark when cranking. Still it just does the occasional backfire. When it did run last year it sounded more like a sewing machine than a tractor but it did run well enough for light work around the yard and had a fair amount of power.

There's more. Last winter I did not drain the antifreeze as in past years. In the spring I found antifreeze in the cylinder. I was hoping that it was a leak through the push rod tube instead of a cracked head. It did not get very cold at all in mid-Michigan last winter. Thinking sticky valves I opened the valve cover and heavily sprayed PB blaster. Everything looked great as i cranked it over and watched the valve spring action. I also drained the old gas and put in new. I am leaving the water out until I get it started. Still just an occasional backfire.

Are my valves sticking? Cracked head and lousy seals? Jumped timing? I plan on rebuilding a lot of this tractor but it has to wait its turn due to another tractor project in the "shop". The "shop" being where my wife would normally park her car. Any suggestions for getting this B running?

[Log in to Reply]   [No Email]
Larry W.

07-17-2002 04:45:48




Report to Moderator
 Re: Backfiring B in reply to Green_in_MI, 07-16-2002 20:17:31  
Sounds like the plug wires are crossed. As for the antifreeze in the engine, options are many, but pushrod tubes are always the first guess.



[Log in to Reply]  [No Email]
Clooney

07-17-2002 03:23:19




Report to Moderator
 Re: Backfiring B in reply to Green_in_MI, 07-16-2002 20:17:31  
Green, does it feel like it has compression when cranking? [if not add a little oil through the spark plug holes & try it]
~You say it has spark? How much & what color. [take an old spark plug & open the gap to 3/16"-1/4" & see if your spark will jump that, & if so is it blue & not yellow? [if it won't jump that gap with a blue spark, tell us what brand & type of mag or distributor you have]
~ Sometimes after it pops a few times you might have to remove the spark plugs & clean them with starting either or break clean [if there is old fuel or an oily residue in the cylinders it can end up on the plugs after a half hearted pop or two & if that happens no amount of cranking will start it.
~If all ok per above, remove both spark plugs & lay them on the block or frame & turn the flywheel slowly in the starting direction. As the L/H cylinder starts to make compression watch the L/H plug as the "L/H impulse" mark on the flywheel lines up with the case mark [at 3 o'clock behind flywheel], the L/H plug should spark when the L/H impulse lines up with the case mark [or close to it].
~If the spark is good & at the correct time, make sure you are getting good fuel flow THROUGH the carb [open the carb drain & make sure you have a good steady stream of fuel form it for at least 30 seconds]
~I all is ok per above you might try pull starting it with another tractor or your truck..... ..

[Log in to Reply]  [No Email]
Green_in_MI

07-18-2002 17:55:57




Report to Moderator
 Re: Re: Backfiring B in reply to Clooney, 07-17-2002 03:23:19  
Thank you for the advice Clooney. I have a Wico C mag on this tractor. I did all your suggested tests with acceptable results except I only got a tiny dribble of gas through the petcock on the bottom of the carb. Does this mean a carb rebuild is in order?



[Log in to Reply]  [No Email]
Clooney

07-18-2002 18:24:14




Report to Moderator
 Re: Re: Re: Backfiring B in reply to Green_in_MI, 07-18-2002 17:55:57  
Green_in_MI, you need to find out if the fuel isn't getting to the carb or is getting to it & not through it.
~Remove the fuel line at the carb & see if you are getting a good flow from that line [is not suspect the fuel strainer or fuel shut-off valve or even the fitting going into the tank], if you are getting good flow there & not out the bottom of the carb suspect needle & seat, carb screen, stuck float or ? in the carb.

[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


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 ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy