Yesterday's Tractor Co. Affordable Parts, Just in Time
Click Here or call 800-853-2651 
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
 
Marketplace
Classified Ads
Photo Ads

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

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

Research & Info
Articles
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
Glossary

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

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
TractorLinks.com
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Enter your email address to receive our newsletter!

subscribe
unsubscribe
  
Garden Tractors Discussion Forum

Re: Small engine problems

[Show Entire Topic]  

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

02-06-2013 21:26:38
71.158.169.173



Report to Moderator

From Wikipedia I quote them on fuel air ratio by weight. “A stoichiometric mixture is the working point that modern engine management systems employing fuel injection attempt to achieve in light load cruise situations. For gasoline fuel, the stoichiometric air–fuel mixture is approximately 13:1”.

So for a 4 cycle engine to run the weight of air needs to be 13 to 14 times the weight of fuel to be burned.

If that fuel air ratio gets out of whack she don’t run so good.

Depending on MFGr and model if there is a gas tank attached to the carb as there are on many 1-7 hp engines there is a fuel pickup tube with a fine wire mesh screen at the bottom which sucks gas off the bottom of the tank. If debris of any kind (crud) clogs the screen, it will need extra vacuum which the choke provides in order to get gas thru the plugged screen and up the tube into the carburetor. Also as said here by someone else in this thread, the main and idle jets can get gunked up. Often there are tiny openings in the ventury region of the carb which need to be cleaned out.
I use a very fine diabetic insulin needle to clean out these tiny openings. Your tip cleaning tool for oxyacetylene torch has a variety of slightly larger reamers for bigger jets. Remember that you only want to remove aluminum oxidation and varnish deposits, NOT metal. If you enlarge a jet even a little it will not meter fuel or air as designed and therefore the engine will not run well either even though everything looks clean!!!! In other words if you ream a jet oversize it will let to much fuel thru and the engine will always run to rich. Another thing to look for is whether the mating surface between carb and engine block is leaking air. If so that alone will cause a lean condition to exist and in turn require more fuel to sucked into the engine so it will run. Get to big a air leak and the engine will starve for fuel even with the choke on. Another place air can leak in is around the throttle shaft. Thats easy to check just by trying to wiggle the throttle shaft. If it wiggles around in the casting you need to consider placing a leather or felt washer on top of it or getting the carb body rebushed.
Many newer small engines have one or more orings which are intended to provide an air tight seal between various components manifolds and the block. If an oring is out of position or damaged it doesn't do it's job. On some carbs there are primer bulbs which are made out of a material which is affected by various gasoline additives. You will find that on higher end equipment the synthetic components will last for years even with the additives. A lot of cheaper engines use easily dissolved tubing and other rubber parts which don't last. If you get a hole in the primer bulb which leaks either fuel or air, there is another problem. Seems like maybe the engine manufacturers are in a p***ing contest with the fuel suppliers over who is to blame. I take the position that the engine is the end user and should be designed for the environment and FUEL which it will be subjected to. Go figure. I have a 20 year old Husqvarna 44 chainsaw with the original fuel lines still in it. It runs great. Gee how could that be? Good plastic tubing obviously. I have repaired 2 year old throw away saws that needed new fuel lines already.

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

Hop to:

TRACTOR   PARTS TRACTOR   MANUALS
Same-Day Shipping! Most of our stocked parts ship the same day you order (M-F).  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. [ More Info ]

Home  |  Forums


Copyright © 1997-2014 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