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Adjusting valves on 280000 and 310000 series briggs & stratton engines

I have two riding lawn mowers I decided to purchase to start re-learning small engine repair on. One has a 287707 14.5HP and the other has a 31H777 18HP Briggs and Stratton engine. Both are OHV Single Cylinder Series; 280000 and 310000 respectively.

First things first, I figure I’ll verify easy to reach parts that usually need inspection and adjusting.

Currently, I’m focused on the OHV Covers underside, i.e. inspecting all the parts and setting valve intake and exhaust rocker arm clearance.

This document shows the gap clearance requirements for the intake and exhaust valve’s with their rocker arm.

However, I haven’t found a repair manual for each engine series yet since the holidays and am therefore not sure what the torque specifications are for the adjustment stud, adjustment nut and adjustment lock screw.

Does anyone know what the repair or other manual for each engine series specifications are and maybe any recommended advice regarding torque specs?

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Why go straight to the valves? The key to fixing anything is the “sling blade” approach. Fuel delivery, spark, then start valves and such.


@Dee Shiznittlebaum I didn't jump straight to the valves. I use the Fuel, Fire and Air approach. If those are all checking out (fuel flows, sparks good, and nothing obstructing or leaking air) or I happen to notice something like blowback through the intake... I'll jump to the valve lash to check and see if in spec.


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Hi @jafinch78 ,

Here’s a link to a service manual which covers the B&S 280000 and 310000 series engines.

Scroll to p.101 for the adjustment procedure and p.170 and p.172 for the torque specifications respectively.

Hopefully this is of some help.

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Hi @jayeff ,

Man, I totally opened up that manual and read the top left corner thinking was only for the 276781 model engine and as like a 270000 series and didn't read into more.

This time... well... page three is about obvious. :-|)

Thanks for posting this!


45lb-in for the rocker arm adjustment nut and adjustment set screw.

60lb-in for the rocker cover.

Wondering what the adjustment stud is set to, if that is 45lb-in also? That was the only other value in question I had.

Thanks again!


Hi @jafinch78 ,

You're welcome.

Glad you read on this time and didn't dismiss it again ;-)


Hi @jayeff ,

Yeah... I have two other engines that are the "L-Head Opposing Twin Cylinder" to study and work with, a 422707 (I think at least as the cowl is missing and only shows 18HP 694cc) and a 402707. Found the manuals for and this time read into some more to verify.

I'll post the link here while at it:



I'll add a comment also regarding on pg. 99 noting that the aluminum pushrod rocker is the lower and intake valve. The steel pushrod rocker is the upper and exhaust valve.


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James Finch sarà eternamente grato.
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