RZT 50 quit and won't start

[Back and forth]

I have a Cub Cadet RZT 50 model 17BA5A7P710 which has never given problems. I was mowing the other day when the engine made a lot of bad noises and quit. Now it won't start and just backfires if it fires at all. It doesn't fire unless I squirt a bit of gas into the carb. The fuel is fresh and the air cleaner is new. I looked at both spark plugs and found one to be dry and a good color while the other one is a bit oily. I don't have a compression tester but I put my finger over the hole and turned over the engine and it has compression. The engine has 472 hrs.
I am now push mowing what took me 6 hrs with the zero turn. It rains a lot lately so I'm getting a bit tired of it.

 

[shiftsuper175607]

I have a Cub Cadet RZT 50 model 17BA5A7P710 which has never given problems. I was mowing the other day when the engine made a lot of bad noises and quit. Now it won't start and just backfires if it fires at all. It doesn't fire unless I squirt a bit of gas into the carb. The fuel is fresh and the air cleaner is new. I looked at both spark plugs and found one to be dry and a good color while the other one is a bit oily. I don't have a compression tester but I put my finger over the hole and turned over the engine and it has compression. The engine has 472 hrs.
I am now push mowing what took me 6 hrs with the zero turn. It rains a lot lately so I'm getting a bit tired of it.

Wild guess from miles away is that something happened with the valves/valve train.

Take the valve cover off and look at the valves...first on the oily side.

 

[Back and forth]

Wild guess from miles away is that something happened with the valves/valve train.

Take the valve cover off and look at the valves...first on the oily side.

I neglected to mention that I did that. I am wondering if the key for the flywheel is broken and the magneto is out of time although that wouldn't explain the oily spark plug.

 

[misha84]

It sounds like piston rings are damaged. Oily spark plug is telltale.

 

[bertsmobile1]

Oily plug
Rings
Inlet valve stem seal
Head gasket
Blocked breather ( would affect both plugs )
Loose valve guides
cracked head.


These are your options

 

[Back and forth]

Oily plug
Rings
Inlet valve stem seal
Head gasket
Blocked breather ( would affect both plugs )
Loose valve guides
cracked head.


These are your options

Thanks folks, that's lots to go on.

 

[shiftsuper175607]

Thanks folks, that's lots to go on.

....engine made a lot of bad noises and quit.....


That sounds like you need to get inside the engine to see what happened.
probably above my pay grade.

 

[mechanic mark]

http://www.mymowerparts.com/pdf/Cub-Cadet-Service-and-Repair-Manuals/

https://www.briggsandstratton.com/n...nginemanuals.html?searchrequested=407577-0317 if B&S engine

http://www.ccdist.com/_assets/_serviceManuals/briggs/273521.pdf engine repair manual B&S

First check oil level on dipstick, is it overfull & smell like gas? If so carburetor problem. Post engine manufacturer as well as all numbers from engine if not B&S engine above. If oil on dipstick looks good check flywheel key for being broken.