445 won't start after replacing parts

[brandeis]

My crankcase was leaking antifreeze from the top and the engine was overheating, so I took it all apart, replaced the water pump with a new one, used form-a-gasket for the crankcase, and put it all back together. Changed the oil, put 15W40 in with a new filter, and I started it and it ran for a couple minutes on low power, but it sounded whiny and wouldn't run on the lowest power, it lacked batter power and would quit. As I cranked the engine speed up after a couple minutes, I heard somewhat of a popping sound and instinct was to turn the tractor off. I tried to turn it back on and it wouldn't start. It turned over, but no starting. Did I break a gear inside the crankcase by chance? Is there some sensor thats telling the engine not to fire or could it just be spark/fuel/air issue? I can rule out the air issue, and I was about to take the spark plugs out to check them, and I can smell fuel.

Why won't it start??

 

[Hooked_on_HP]

What are you working on? A 455 what?
Bill

 

[brandeis]

its a 445 john deere lawn tractor with a 22hp kawasaki engine, model number FD620D

 

[Gittyup]

Do you have the plastic cam gear? If so, it may have broken. Would have been easy to replace while you had the water pump off. I think sometimes the governor gear can get damaged when you change the water pump too. Your problem almost sounds like its the governor. Did you set the timing back right when you put it together?

Might want to move thread to the JD forum where you are likely to get more informed answers.

 

[brandeis]

You were absolutely right. The cam gear was broken as well as the governor gear. Also the oil pump gear had a couple of chipped teeth. If I get these new gears and put them in, what's guaranteeing me that it won't break again? why did they brake in the first place just from replacing the water pump? The crankshaft gear was fine, and I can't tell if the cam gear is plastic or not but it does seem pretty brittle. And I didn't think I messed with the timing at all. I'm going to upload a picture just to give you an idea of what it looked like. It is pretty nuts to see the gears broken into pieces. Should I just replace the whole thing? there's an engine for 900 bones on eBay, and a kit with the gears for 250. I don't know if its worth it if I just end up breaking the dumb gears again.