Ok I've got a new issue for you guys.
I have a 13 yr old Murray riding mower that just won't die!!!
It has a 17HP Tecumseh engine. It has now gotten to where it doesn't want to crank past TDC. I've even tried jumping it from my pickup straight to the starter (brand new starter).
It spins fine until it hits TDC and it will literally bounce back against the starter. I can turn the motor backwards until it hits compression and try it again and generally after several ties it will finally fire up. Runs like a top once it's running.
I've had a couple of folks tell me that they think it may need a valve adjustment.
What do you guys think.
Also I'm not sure where to start on the valves for this thing.
What's the process for adjustment and what's the proper gap?
Model OHV17
Family STP490U1G2RA
490CC

Thanks guys!!!

 

Timing. If the spark hits before TDC, it won't move... I know from personal experience. Get it running and it will run like a raped ape because the timing is helping but not when it tries to start. This was on a old Wheel Horse, 6hp. To start it, we would get the 12hp WH running, twist the belt, hook it up to the pulley of the 6 hp, engaged clutch, mess with choke and throttle until it fired, kicked the belt off, and away we went. Did you know the the bolt pattern for the old WH is a 5x5.5 lug pattern? Opened up a whole new arena for tire/wheel combos...

 

it might have small fuel leak causing hydro lock it might have sheared the crank key causing the timing to be off .did you try and turn it over with out the spark plug?

 

agree, going for a shear; missing valve spring that set timing cam forward. either way -tear it down. it earned it, lol.

 

Don't you need a battery, even if dead, to complete the circuit on the riders? I was doing that with my old cub cadet and it would jump back. Finally got a squared away battery and it rolled fine.

 

Well I googled it in several ways and finally found several forums that refer to a compression release on these Techumseh OHVs. I most likely need the cam repair kit. The kit replaces the out of spec compression release. it would take about 5 min.s to install except according to the forum posts I've read this requires pulling the engine to install the new compression release.

 

Had a brand new battery and starter. When that didn't work I jumped past the battery directly to the starter to get the most juice to the starter as possible. It'll start about one time out of 20.