Craftsman Riding Mower

BJS

Member
My mower will start once but will not start again and it will not even turn by hand, until I remove the spark plug. Then it spins freely. It is a B&S engine 17hp. OHV. Any help would be greatly appreciated. Thank you.
BJS
 
Has been cover MANY times in this garden tractor forum. Just start digging back a few pag3s. First is valve settings. That usually fixes them. If you have a broken releas then you need to take engine apart. 98 of the time it is just setting the valves.
 
Valves out of adjustment and not allowing the compression release to work properly.

Just about bet that if you pull the valve cover you will find that the exhaust valve (bottom rocker) is way out of adjustment..

Both intake and exhaust valves on newer OHV B&S engines can be set in the middle of the range at 0.004" (four thousandths).

Valves becoming out of adjustment is common on newer B&S OHV engines..
 
i would start by taking the valve cover off and checking for bent or broken push rod. very common on that engine.
 
(quoted from post at 19:29:57 09/21/17) i would start by taking the valve cover off and checking for bent or broken push rod. very common on that engine.

I will touch on Tractorguy's reply.

The Intake valve's push rod is aluminum and the exhaust is steel on some 17 hp engines (and maybe others). The intake push rod is known to crack and/or snap at the oil hole where it passes through the rubber bushing/guide.

If you find an aluminum push rod. It is a good idea to replace it with a steel exhaust one. Both are the same diameter and length. I never could find a good reason for using a single aluminum push rod other than B&S found that they could save a penny on cost.
 
The reason Briggs used an aluminum pushrod on the intake is because aluminum expands more when heated up than steel. They only use the aluminum pushrod on the intake side, because the exhaust valve runs hotter and it gets the steel pushrod. That way the valve clearance is more optimum throughout the warm up phase of the engine.
 

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