Baffled

[Keevalee]

I have a B & S 19.5hp 31P677 on my John Deere lawn tractor. It wouldn't start because the compression release mechanism on the cam shaft had come apart. I have put a new cam shaft in along with tappets and adjusted the valves to factory specs. I had a bit of a problem getting the timing marks to line up, I couldn't get it in because of the push rod being in the way. I got it in and went to TDC and adjusted the valves. I am under the impression the I received the wrong cam shaft. It still is not starting and is difficult to turn over. Is there anything that can be done without tearing it back down and reordering another camshaft?

 

[Scrubcadet10]

Should have gotten a 793880 cam or a 84005207 cam.
Do you have a pair of jumper cables? Bypass the tractor wiring using those, Neg - to a good ground on the tractor and mower battery Neg -, + to battery +, then touch your positive lead to the starter lug, expect some sparks. If the engine cranks normally you have a bad ground, loose cable or bad connection....
If it still cranks bad, remove the jumpers, and check the battery voltage while cranking, or attempting to crank, if it dips below 10v or so, i would suspect a bad battery. Most auto part stores will load test a battery for free.
Take the spark plug out and try to crank, if it cranks normally and faster, i would suspect an internal issue.
Intake .003in-.005in/.07-.12mm
Exhaust .005in-.007in/.12-.18mm

 

[StarTech]

Also can be that push rods aren't seated in the lifters. I always loosen the rockers whenever replacing and verify the push are in the lifter and not on the side of them.