Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Garden Tractors Discussion Forum

8 Hp. Tecumseh snowking backfires

Welcome Guest, Log in or Register
Author  [Modern View]
49 Studie

12-27-2010 18:53:19

Report to Moderator

8 hp.tecumseh runs rough,pops and backfires at high idle,runs fair under load,cleaned carb and fuel system several times.Any advice?Float setting wrong?Checked for intake leaks,comprssion okay.Thanks for any advice.

[Log in to Reply]   [No Email]

12-28-2010 13:45:36

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-27-2010 18:53:19  
Weak spark, retarded ignition timing, and a lean mixture can all give those symptoms. Since the engine is fairly simple, it usually make sense to pull the carb apart, yank the flywheel off, and pull the head, i.e. check everything.

With the carb, the fuel seat can fall out (very common). Nothing holds it in but a tight fit. Also the main jet-adjuster tends to get full for crud. Just remove it with a 7/16" wrench and eye-ball it. Jiggle the float and make sure it's empty aslo.

Tecumseh (R.E. Pehlon) aftermarket condensors are often crap. So, it's imperitive to check the condensor (for short, for capacitance, and for holding a charge). Make sure no wires were left hanging out and got cut by the flwheel (also common). After setting the point gap, check when timing is taking place and adjust the stator plate if needed.

You mentioned the possbility of a valve sticking. Yes, it's possible and also very easy to check. Sticking exhaust valves are more common with Kohlers, burnt ex-valves more common in Tecumsehs, and loose exhaust seats in Briggs. Just pop the head off and look at the valve face - and check how tight it is. Taking a head off and on is a ten minute job and a new head gasket is rarely needed.

When we used to take in these things for repair, diagnosis of one particular problem was rarely worth the bother. That mainly because the engines are so simple, you can pull apart and check all the systems pretty quick.

A sticking exhaust valve will not sound the same as when an engine has weak spark, late spark, and/or a lean mixture - but the difference can be a subtle one.

[Log in to Reply]  [No Email]

12-28-2010 07:34:49

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-27-2010 18:53:19  
what others said and also... A lot of these engines had two small square magnets epoxyed to the inside of the flywheel which when passed by the coil made the power for the spark. These have a tendancy to rust loose and move around. Don't know if this would change timing because the points still release the spark energy but it would cause problems. Most older engines had the magnet made right into the flywheel but not these. More than likely bad plug or lean mixture.

[Log in to Reply]  [No Email]
49 Studie

12-28-2010 06:57:27

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-27-2010 18:53:19  
Thanks for the input,it is a older engine with brass float and adjustable jets,mostly seems to run lean at high idle,will run better when first started.Any possibility of a valve warping as it warms up?Thanks again.

[Log in to Reply]  [No Email]
joe csuti

12-28-2010 13:33:40

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-28-2010 06:57:27  
Might also try re-torqueing head bolts or replaceing head gasket,same may start to leak when eng gets hot.If valve warped it would be a problem at all speeds,if eng getting tired & burning oil a more probable cause of problem would be carbon on valve stems causeing valves to stick at low speed,worn valve guides,carbon buildup on valve seat or low compression when eng gets hot due to worn cyl/rings.

[Log in to Reply]  [No Email]
joe csuti

12-28-2010 02:17:58

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-27-2010 18:53:19  
If eng has a fixed hi speed jet,the most common cause of problem would be dirt/varnish in main jet & low speed/idle passages of carb body,these carbs normally run lean,the slighest restriction in passages will cause fuel mixture to go lean,also if you haven't done so already,install a new spark plug,you may just have a plug going bad.Other possible cause's,carbon on valve stems causeing valves to stick,carbon buildup on valve face/valve seat,problem in ign module,flywheel key bent,changeing ign timing.

[Log in to Reply]  [No Email]

12-27-2010 19:37:12

Report to Moderator
 Re: 8 Hp. Tecumseh snowking backfires in reply to 49 Studie, 12-27-2010 18:53:19  
Check valve adjustment. Intake may not be closing completely before spark.

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

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

Home  |  Forums

Copyright © 1997-2016 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