Head gasket?

Kparent

Member
Joined
Jun 15, 2022
Threads
4
Messages
25
All four valves were set to .005 when the pushrods were recently replaced. Upon rechecking all four are still at .005.
thx
 

Kparent

Member
Joined
Jun 15, 2022
Threads
4
Messages
25
How much does my methodology affect the settings? I saw two methods of setting these. One, and what I did was, bring the cylinder to top dead center, both valves closed. Set both at the same time. The other method was to bring the cylinder to top dead center but advance the flywheel an additional quarter of an inch. Did I set them with the piston in the wrong place?
 

Scrubcadet10

Moderator
Staff member
Joined
Sep 24, 2017
Threads
266
Messages
6,630
I can't recall exactly why the recommendation is to move the piston 1/4" past TDC,
I use the OVOOVC method with no comebacks or trouble.
One Valve Open, One Valve Closed, adjust the valve that is closed.
 

Kparent

Member
Joined
Jun 15, 2022
Threads
4
Messages
25
I can't recall exactly why the recommendation is to move the piston 1/4" past TDC,
I use the OVOOVC method with no comebacks or trouble.
One Valve Open, One Valve Closed, adjust the valve that is closed.
Alright. I’ll try that.
Thank you
 

Kparent

Member
Joined
Jun 15, 2022
Threads
4
Messages
25
I opened the valve covers only to find a bent exhaust pushrod. The intake rod is fine. Both of the rods on this side were replaced last week.
The rods on the opposite side were replaced two weeks ago while replacing that head. Both of those rods are fine.
I used the machine once to mow the lawn from the time of replacing all these rods to now. Machine ran fine except for the restarting problem which was the original reason to begin this thread.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
65
Messages
24,995
Probably
Pushrods bend because the cam is pushing the push rod but the valve can not move any further
The usual reasons are a stuck valve or a slipped valve guide
Valve guides slip because the heads got way too hot and lost their temper
IF this is the case then the head is scrap metal unless you have a friend who restores motorcycles & is inclined to make & fit oversized guides fr a really nice burbon .

Now this is a sign of a bigger problem, your head is getting way too hot
While this can be operator error like running then engine at lower speeds than WFO or failing to clean the cooling fins, I have found several Kohlers that run way too lean thus way too hot requiring drilling out the main jet a TINY amount ( next size jet drill larger which is 0.0001" in my kit )
 

Kparent

Member
Joined
Jun 15, 2022
Threads
4
Messages
25
The new head arrived today. It has been replaced. the lash was set at .004 using the method prescribed.
the engine had a tough time getting past compression. This requires turning the key two or three times until it turns over. Once the engine turns over it starts right away and runs smoothly.
upon closer inspection the exhaust valve guides on both head were at least .0375” higher than the intake guides in both heads. I ran the engine slow for a couple minutes then slowly brought it to full speed then slowed it down before shutting it off. It ran smoothly through the speed changes. I did not want to run it long for fear of heat buildup.
though I’m confident taking the carburetor off I do not have the tools necessary to drill the main jet. I’ll speak to a local repair shop Monday for assistance with this.
I’m still baffled by tough starting. The camshaft on this machine is not made with a compression release built in. The “easy spin” system seems to depend on an “zero lift zone on the cam lobe” (according to “how to repair Briggs and Stratton engines”). Do I need to change the cams or can this problem be solved with the lash setting?
thank you
 

Scrubcadet10

Moderator
Staff member
Joined
Sep 24, 2017
Threads
266
Messages
6,630
i wonder, if something broke the pushrods originally could have damaged the compression relief as well>
Need to get a volt meter and check the voltage while cranking.
 
Top