169 Backfiring then stops
 

My 169 is having some troubles mowing. After about 40 minutes or so of mowing it will suddenly start poping bad out the exhaust then stop. When I try to restart the engine spins over very easy and will not restart. After letting it sit for a while it starts and runs just fine.

I first thought it was the condenser so I put a brand new one on. However that would not allow it to turn over easy when trying to restart.

I think it may now be a stuck exhaust valve as when it happens the engine turns over very easy. Any ideas on how to resolve the issue. Should I remove the valve cover and spray carb cleaner or some other solvent onto the valve stems, then reoil?

Any ideas?

Thanks

Try another coil first.
Seen it happen several times before.
Make sure its a resistor coil (one with a built in resistor)
Easier than pulling the motor apart.
Can always do that later if the coil doesn't solve the problem.

I had a 1200 that did the same thing.
The exhaust valve is getting hot and sticking open.
First, retime the engine. The procedure is found here: http://mgonitzke.net16.net/tools/static_timing.pdf
Then put a healthy dose of Marvel Mystery Oil in your gas and run it. Should cure the problem. After you run that tank of fuel through, run the MMO in the ratio recommended on the bottle every tank of fuel. It should prevent the problem from returning.

Thanks everyone, I will be trying your suggestions and hopefully get the issue resolved.

Well I put in some MMO and it has been running like a top with no sudden stalls. Mowed for about 2 hours so thats great.

Now I still want to check the timing as it does start a little hard when warm. However I could not find the timing hole in the fan shroud. I have a K301 and a K241 and I see the inspection hole on them however they are on different sides. Any idea where they put the inspection hole on the 169 K341?

If you backfire hard, then you may also want to replace your plug just in case it is fouled.

Cub Cadet 123

The timing hole on my K321 is on the right side of the engine (as if you are sitting on the machine) behind the S/G bracket. Maybe the same as the 16 horse?

Wanted to post incase someone else has the same question about the timing hole on the 16hp K341. The timing hole is located on the back bearing plate of the engine and not on the blower cover. It is on the right hand side of the engine when your siting on the tractor. Its right between the Gen/Starter and the frame rail on the back engine bearing plate.