Hi,
Sorry for being a newbie to small engine repair. I was given this Craftsman lawnmower years ago.
It sort of working for me with troubles. Recently it simplely died. No compression but there
is sparks.I did all the clean up and replace with new parts on carburetor and new fuel
but no dice. I then proceed to remove the cover. When manually rotating the flywheel I see the
piston moving in and out smoothly and the wall is not scored. The exhaust valve has much carbon
deposit and stops at about 1/8 inch above the valve channel. It can use some good cleaning.
Both valves are not moving when flywheel is being rotated. I make sure they are not stuck in
there because old sticky gum. In valve chamber,I can move both valve shaft which should be in
contact with camshaft. They have that loosely feel. And yes there are no movements on
these rods when flywheel is being rotated. Am I correct to think when rotating the flywheel the
piston should travel and camshaft should push the valve shaft to open the valve?
I wish some more advanced member can give insight on this matter. Thanks.
By turning the flywheel 2 complete revolutions each valve should open and close once. How much gap do you have been the valve stem and the top of the tappet.
#3
EngineMan
If the valve lifters are not moving you have a problem with the camshaft.
Yes,it looks rather terminal by now. Sigh! It did not see much action over the years. The measured valve clearance is .005 U.S. Service Menu said .004 to .008. But valve lifters do not move at all while rotating flywheel. It appears either worn out / broken / out of position lifters or camshaft. The cost for sending in for a professional job is probably prohibitive. Thanks everyone for giving me some ideas about this mower.
Very common for a little rust on the valve stem to make them stick
Post modified because as Engine man pointed out it is a side valve engine, not an OHV and where possible information posted on forums should always be correct.
I shall now sit in the naughty corner wearing the Dunce hat
#6
EngineMan
There are no push rods on that engine, but there maybe rust on the stem...!
So I removed the spring and the valve stem and used my finger to press on the lifter I then rotated the flywheel. I felt a bit of friction from contacting the camshaft. Not strong enough to move the valve stem obviousl
#8
EngineMan
Than you next step is to check the cams on the camshaft.
#9
upupandaway
Adam, please see PM.
#10
Boudreaux In Eunice La.
That valve tappet he pointing at is the exhaust valve..... That is where the comp release is at.... Maybe just maybe he is not turning the engine over 4 or 5 times to see the valves move the correct way......
So I ran to my garage and turned the flywheel few more turns but the valves still not moving.... . It looks to me the valve lifters are disengaged to the camshaft for whatever reasons. I'll wait till the necessary parts come in to open up the engine see what the real story there is.
wrong way round.
Flip the engine upside down and pull the sump off.
Then look at what is there and order what you need.
No good buying parts now only to find the crank is kaput when you pull it down.
