Welcome! Please use the navigational links on your left to explore our website.

Company Logo Shop Now
   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
Kountry Life
Garden Tractors Discussion Forum

Using a Compression Leak Tester

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

10-23-2018 16:11:49

Report to Moderator

Do I need to figure out someway to lock the crankshaft on an older 11HP Briggs and Straton engine in a lawn tractor when using a compression leak tester. Working on a no start problem with gas being spit out of the carburetor when trying to start. Will need to put the head back on as I took it off to insure I did not have a sticking valve Both intake and exhaust seem to open and close fine when turning the engine over by hand.
Thanks for any help and or suggestions, idea.

[Log in to Reply]   [No Email]

10-31-2018 15:52:39

Report to Moderator
 Re: Using a Compression Leak Tester in reply to wsmm, 10-23-2018 16:11:49  
Quoting Removed, click Modern View to see

Additional Info. Engine is a Briggs and Stratton model 25707 type 0622 02. Electric start only, don't believe it has a compression release. Ran a leak down test on it, did not need to lock the crank. Was able to determine it was leaking at the intake valve. Both intake and exhaust had a lot of carbon on each valve. Cleaned up both valves. Odd intake valve had keepers on valve, exhaust valve had a notched retainer. Intake valve clearance was good, no clearance on exhaust valve. Clearanced and checked clearance on exhaust valve, now in specs. Will lap both valves in the next few days and then run another leak down test. If still bad will probably just switch the engine from my other lawn tractor with a bad transmission to it.

[Log in to Reply]  [No Email]

10-24-2018 06:07:07

Report to Moderator
 Re: Using a Compression Leak Tester in reply to wsmm, 10-23-2018 16:11:49  
On the woodruff key locking the flywheel to the crankshaft, If it's even partially sheared that can be a problem also. Never thought that the few degrees of error in timing caused by such would cause hard starting and a problem in eventually actually running, but it happened to me. New key and away she went.

Just takes a second, pop the flywheel nut and have a quick look.

[Log in to Reply]  [No Email]
Mule Meat

10-23-2018 22:13:14

Report to Moderator
 Re: Using a Compression Leak Tester in reply to wsmm, 10-23-2018 16:11:49  
I have found that a lot of problems with gas spitting Briggs engines to be carb related. Mainly the float.

Remove the carb and then the bowl.

Turn the carb upside down and look at the float. It should be level.
If not. Remove the float and the needle valve. Carefully heat the small tab that contacts the needle and bend a small amount. Then cool it with a few drops of water.

Reinstall everything as it should be and check the float again. If needed repeat the heating process and bending until the float sits level.
Remove and check that the Hi and Lo speed adjusting screws are not bent or damaged.

If OK. Reinstall them and turn in until they stop and then back them out 1 1/4 turn and try starting the engine. If it runs adjust the speed screws until the engine is running correctly.


One last thing. Have you checked the flywheel key to make sure that it had not sheared and threw the engine out of time?

I have always rotated the piston to near BDC on the Power stroke for pressure testing. If the valves are seating good. The pressure most times will force the piston down to BDC as pressure builds/

[Log in to Reply]  [No Email]

10-23-2018 19:07:40

Report to Moderator
 Re: Using a Compression Leak Tester in reply to wsmm, 10-23-2018 16:11:49  
Yes, you will have to lock the crank at top dead center (TDC) on the power stroke with both valves closed. There is another TDC between the exhaust and intake strokes, but that will give you false readings because of cam overlap holding the valve open. In other words, the exhaust valve is not quite fully closed and the intake valve is beginning to open.

Actually, you may need to be part way down the cylinder on the power stroke to be sure the intake valve is not on the compression release, depending on which engine it is.

Before you put the head back on, roll the engine over to TDC on the power stroke and see if you can turn either valve with your fingers. if you can spin it, its not closing fully.

[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 © 1997-2018 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