# Valve Lash Settings for 20hp B&S ?



## 7394

Hello- 

Can anyone Please tell me the valve lash settings for my 2008 B&S (Single cylinder) engine in my Craftsman 46" riding mower ? 

Engine model # 331777-1107-B1 


Thanks in Advance..


----------



## OptsyEagle

Edit: Sorry not absolute sure. Perhaps someone else has the exact numbers.


----------



## usmcgrunt

The intake valves are .003 to .005,the exhaust valves are .003 to .005.Pay particular attention to the ¼” past top dead center notation for setting the clearance on page 21 of section 1 of the manual (OR) the adjustment procedure below. Hope this helps.

Adjustment procedure-
Fixing a Hard-to-Start Briggs & Stratton Lawn Mower


----------



## OptsyEagle

Now am I just using the wrong model number here. When I look at the service manual on page 174 for Model 330000 Vertical Series motors, I see:

intake: 0.003" to 0.005"
exhaust: 0.003 to 0.005"

Where am I going wrong here. Which spec matches his model number?


----------



## usmcgrunt

OptsyEagle said:


> Now am I just using the wrong model number here. When I look at the service manual on page 174 for Model 330000 Vertical Series motors, I see:
> 
> intake: 0.003" to 0.005"
> exhaust: 0.003 to 0.005"
> 
> Where am I going wrong here. Which spec matches his model number?


You are correct,.003 to .005 are the specs for both valves.:thumbsup:

Changed to correct specs in post #3


----------



## 7394

Excellent info & links,:thumbsup: *Thank You usmcgrunt..* 

I had not taken into consideration about the compression releases on the cam lobes, for the 1/4" past TDC on each, before setting lash.. 

Intersting the In. & Ex. have same specs (.003-.005) ..And that the exhaust could have a Steel pushrod, vs intake aluminum....

I saved both links, naturally.. Thanks again. 

My valves need set, but the reason that caused it was the rocker stud(s) backed out a bit from the head.. This caused some oil to seep past the threads, & drip externally. 

Never had anything like that EVER happen..Have to get them cleaned & loc-tited, then re-seated first.... 

Possible cause might have been shutting off the fuel petcock & running engine till it dies, after each use.. That's only thing I can think of..


----------



## 7394

PS: Engine starts easily & Runs great, besides the very minor valve clatter, I did notice a slight increase in fuel usage. 

I think that could be related to late valve timing. aka loose lash setting(s).


----------



## 7394

*Update*

*usmcgrunt- * Thank You Sir...:thumbsup:

Top rocker stud had loosened (Exhaust)...Now corrected. Exhaust pushrod is Steel, as link stated. Intake pushrod is aluminum... 

Valves are set to spec.. And runs like new again, & obviously much quieter as well..

Didn't think I was missing any power (prior), but I was wrong..

And gas mileage has improved as well..


----------



## usmcgrunt

Great job.:thumbsup::thumbsup:
You did all the work,we just gave you the info you needed.


----------



## 7394

usmcgrunt said:


> Great job.:thumbsup::thumbsup:
> You did all the work,we just gave you the info you needed.


True, however without the valuable Info about 1/4" past TDC on comp stroke, would have had me removing the valve cover more than the one time I had to.. 

& I'm sure scratching my head would have been involved as well.. :thumbsup:

Again Thanks, & also for the links I saved !!!!


----------

