Picked up a Craftsman YT4000 with 24hp Briggs that was running poorly and popping etc. Cylinder 1 intake valve was too loose, and exhaust valve was way, way too tight. Runs fine after adjusting them. Was just wondering what causes them to get so far out of adjustment. Only has 170 hours on it.
What causes valves to get out of adjustment
- Thread starter slow030
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bertsmobile1
Lawn Royalty
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Probably mal adjusted from the factory.
This is why they are supposed to be checked on the first service some where from 10 to 50 hours.
After that there is wear, lots of moving bits that wear and then there is excessive heat that allows the pivot bolt to loosen or pull out and the valve stem to shift .
Severe over heating will allow the valve seat to loosen, particularly the intake .
This is why they are supposed to be checked on the first service some where from 10 to 50 hours.
After that there is wear, lots of moving bits that wear and then there is excessive heat that allows the pivot bolt to loosen or pull out and the valve stem to shift .
Severe over heating will allow the valve seat to loosen, particularly the intake .
mitchstein443
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not sure on that particular motor, but on my kohler engine in an older dyt4000 craftsman I found tht there is a locking nut on the valve adjustment, a little allen key screw to lock the nut in place once the valves are adjusted..
Well they like to break off.. which is how I got this moer for 100$ after the previous owner replaced the coil, plugs, burned the strter out trying ot get it to start, the exhaust vlve nut was so loose the rocker arm wwas just swinging not touching the valve stem at all..
got the replacement, vlave, locking nut with locking allen screw, new vlalve stud from amzon for under 20 bucks, so I did both itake and exhaust.. worked for 5 years of daily use and then hppened agin... should get anther 5 years from it now.. lol
Well they like to break off.. which is how I got this moer for 100$ after the previous owner replaced the coil, plugs, burned the strter out trying ot get it to start, the exhaust vlve nut was so loose the rocker arm wwas just swinging not touching the valve stem at all..
got the replacement, vlave, locking nut with locking allen screw, new vlalve stud from amzon for under 20 bucks, so I did both itake and exhaust.. worked for 5 years of daily use and then hppened agin... should get anther 5 years from it now.. lol
Suggestion:
You'll want to check your adjustments again in (say) 10 hrs. You should NOT see any changes from where you set them. That would prove the issue comes from no maintenance by the PO, rather than some type of engine damage.
You'll want to check your adjustments again in (say) 10 hrs. You should NOT see any changes from where you set them. That would prove the issue comes from no maintenance by the PO, rather than some type of engine damage.