Poulan 17.5 hp wont start

bertsmobile1

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Nov 29, 2014
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Pull the spark plug and rotate the engine by hand while watching the valves.
Bottom inlet top exhaust.
The inlet will close then open a tiny amount for decompression.
rotate the engine till TDC the go past about 1/4" of piston drop.
The engine is now ready for valve lash adjustment.
It is backwards to what is usual.
The grub screw in the middle is the locking mechanism and the nut is the adjustment.
So loosen off the grub screw, either an Allen screw or a Torx screw.
Turn the outer nut to adjust the gap .
Hold it firm then tighten the grub screw,
Set it tight as when tightening the grub screw the gap tends to close a thou or two .
Run the engine for 10 minutes
Let it get stone cold ( about 2 beers worth ) then recheck.
Grease the gasket when happy with the settings and refit the rocker cover.
If you can not get the engine to crank properly with the gaps set to the tightest setting then the cam is worn & needs to be replaced.
I have run an engine at 0.002" on the inlet but eventually the valve seat let go , which was expected but the owner did not want to have the cam replaced.
 

leink

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Jul 15, 2017
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:thumbsup: after setting valves more times than i care to count,:confused2: i returned to the basics, and took a closer look.........found intake push rod bent,which prevented a proper adjustment.
started and running fine now! thanks to all:laughing:
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
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24,647
:thumbsup: after setting valves more times than i care to count,:confused2: i returned to the basics, and took a closer look.........found intake push rod bent,which prevented a proper adjustment.
started and running fine now! thanks to all:laughing:

Push rod bent and stud loose are classic symptoms of an overheated head causing the alloy to go soft.
If it keeps giving you problems then it is new head time.
make sure you pull the blower cover off at the beginning of each new season & clean around the fins.
Over winter all sots or things seem to mistke your mower for their Hilton ( & I ain't talking Paris )
 
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Yes mice will build a nest in there and cause heating issues..

Where you from Mon Ami. ??????
 
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