Motor will not turn over?

[jhngardner367]

First,check the air gap for the coil(s). They should be 0.010". Also,try spraying some fuel into the intake,while rolling it over.and see if it runs,or backfires. If it backfires through the intake you could have a valve hanging up.
If you pull the engine case apart, check the timing marks,carefully.

 

[tim2]

Well I was hoping more people would give me there ideas. I guess today I will check the gap on the armature and pull the head off and see what I can find that might not be correct. I think it is a push rod that is not seated on the valve. I sure want to hear this thing running soon. Thanks for the advice, sure hoping for more.

 

[Fish]

I would say that you should check your flywheel key now, it is probably sheared due to insufficient torque on the flywheel nut.

 

[tim2]

I have spent the last three hours trying to figure out the problem. I checked the gaping, removed the flywheel and replaced the key. Neither helped but I had to try them. I just pulled the head back off and it looks like one of the pushrods was not seated in the cup inside the head. I am going to the store and get some sealant for the head gasket and give it another shot. I sure hope this corrects the issue.

 

[tim2]

Well I am ready to junk this thing. I gaped the armature to .010, replace the fly wheel key, took off the head and then reassembled it. I got the push rods installed and try to start it. BACKFIRE through the carb again.......... So what else can I do? The only thing I can think of is pull the push rods and turn the motor one complete revolution and then reinstall the push rods and give it a try. Anyone with another idea pleaseeeeeee chime on in I need help.

 

[Fish]

When you say you replaced the flywheel key, why did you? Was it sheared, or in one piece?

 

[tim2]

I was just following your advice to check the torque and said I might as well check the key also. The key was slightly twisted due to the connecting rod breaking and it was sheared slightly. I have it all back together and still cannot get the motor to start. I believe it has to be in the timing but cannot for the life of me get it set correctly.

 

[tim2]

I reckon it is time to tear the motor open again and check the marks on the gears one more time.

 

[tim2]

Does anyone have the valve clearance measurement for a B&S 15.5hp motor? I would like to check that before I tear it all apart again.

 

[tybilly]

Does anyone have the valve clearance measurement for a B&S 15.5hp motor? I would like to check that before I tear it all apart again.

go to mymowerparts.com you can download a manual pdf for that engine