Return to the Lawn Mowers Forum | Post a Follow-Up

o
Help Needed -- Tecumseh / Lauson Diaphragm Carburetor

clip this post email this post what is this?
see most clipped and recent clippings
Posted by chesapeakebeach (My Page) on
Tue, May 11, 10 at 20:00

I'm working on an early 1980s Craftsman Edger with a 3.0 HP horizontal shaft Tecumseh engine and Lauson diaphram carburetor. The edger is Sears model 536871100 and the engine is Sears part 143711022. The machine had been in storage for a long time, and then after I first got it, put in fresh gas, took the head off the engine and removed the built-up crud from the combustion chamber, etc. and started it, it ran fine, but then it got into the habit of running for 10 minutes before stopping. Now it won't start at all. The spark plug is new and the air filter is new.

I had never cleaned the carburetor, so I tore into it with carb cleaner spray and made sure all the passages were clear. I will be putting in a carburetor repair kit (520312) as the needle and seat looked questionable and the seals around the needles were getting rotten.

A couple questions:

* Anything else anyone can advise me to check that would contribute to a no-start condition?
* What are the appropriate choke and throttle settings at start-up (choke can be off, 1/4, 1/2, 3/4, or full)?
* Where can I get instructions on setting the carburetor needle screws (one large, one small -- #10 and #14 on the diagram linked at
http://www.searspartsdirect.com/partsdirect/getSubComp.pd?modelNumber= 143711022&productCategoryId=1503500&brandId=0247&brandDescription=CRAF TSMAN&modelName=CRAFTSMAN-4-CYCLE-ENGINE&diagramPageId=00001&component Description=REPLACEMENT PARTS&documentId=00008114&blt=06

Thanks in advance.

Here is a link that might be useful: Edger carb diagram

Follow-Up Postings:

o
RE: Help Needed -- Tecumseh / Lauson Diaphragm Carburetor

clip this post email this post what is this?
see most clipped and recent clippings
  • Posted by canguy British Columbia (My Page) on
    Tue, May 11, 10 at 21:17

The mixture screws should be set 1 1/8 turns out for initial start. The choke would normally be fully closed.
Do you have good compression and a strong spark?

o
RE: Help Needed -- Tecumseh / Lauson Diaphragm Carburetor

clip this post email this post what is this?
see most clipped and recent clippings

Thanks, canguy -- compression seems good, will check spark. Ordered carburetor rebuild kit today and it should be here early next week. If spark looks OK and carb rebuild doesn't help, I'll do a gasket rebuild kit as well to make sure there aren't leaks anywhere.

o
RE: Help Needed -- Tecumseh / Lauson Diaphragm Carburetor

clip this post email this post what is this?
see most clipped and recent clippings

I have the same model Edger/Engine and unfortunately, I do not have the user's manual and am not too familiar with small engines. I was just wondering what type of oil and how much of it should I put in the engine.

Thanks in advance,

Kash

o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Lawn Mowers Forum

Instructions

  • You must be a registered member and logged in to post messages on our forums.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review the contents and make changes.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • It is illegal to post copyrighted material without the owner's consent.
  • HTML codes are allowed in the message field only.
  • No advertising is allowed in any of the forums.
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.



 
Click here to learn more about in-text links on this page.