What spring do I need?

[Martini]

Craftsman Model: 247.37031

Briggs and Stratton Model: 126M02-6863-F1

The light, almost fully stretched spring in the pic is a spring from a pen. I lost the original spring last year which was much lighter. The mower makes a backfire sound sometimes when shutting off and I'm wondering if it's due to the wrong spring being on there.


In the replacement parts list in the link below, the only springs are the choke return spring (which I believe is the heavier spring in the pic) and a spring detent (which looks like a small internal part).

Any help would be appreciated.


https://shop.briggsandstratton.com/...2-6863-F1/Carburetor/126M026863F1/103320003/y

 

[Scrubcadet10]

alrighty, you have an engine with an Auto Choke it, and you need this spring https://www.jackssmallengines.com/jacks-parts-lookup/part/briggs-stratton/690354
part number 690354.
and if you're interested here's how to the auto choke system works. https://youtu.be/YAqVcdZOZE4?t=113

EDIT for future reference, i gave the wrong part number.

 

[Martini]

Isn't that the heavy spring in the pic I took?

Maybe 209A or 209B in the diagram on the below web page?:

https://shop.briggsandstratton.com/...ake,_Governor_Spring/126M026863F1/103320006/y

 

[Scrubcadet10]

no, those are governor springs, you can bend the tab it is hooked to to raise/lower engine RPM's
you need the choke return spring, found one a little cheaper on amazon https://www.amazon.com/Briggs-Stratton-690354-Return-Replaces/dp/B002WNY8TW

 

[Martini]

Can you please take another look at the pic I took? The spring I need replaced is the one the one that was in the place of the pen spring now on the mower (the one almost all the way stretched). The heavier spring in the pic I do not need and looks like the choke return spring you're recommending. The spring I lost was very light.

 

[Scrubcadet10]

Here ya go! i jostled my memory of when i worked on an auto choke last year.
https://www.jackssmallengines.com/jacks-parts-lookup/part/briggs-stratton/790849

it was in a different diagram. I had looked at the wrong diagram number. the diagram i looked at showed different type carburetors and the one i saw was for the non autochoke engine :confused2:
sorry for any confusion i caused.

 

[Martini]

Yes, I think that's it! :smile: Thank you for the help, much appreciated!

 

[Scrubcadet10]

you are very welcome!
for future reference or any other problems

the tab circled in yellow, you can bend it outwards with some pliers to increase engine speed.
:biggrin:

 

[bogdaN]

That is same engine that do not want to start --the other post.I see U got lot good info,and still no start.From pic,s springs are all mess-up.What is compression on that engine?Dan

 

[bogdaN]

Spring for air vane auto-choke is 790849.