Lawn Mower Won't Start, Backfires

Hi,

I've run out of things to check, so I'm hoping someone familiar with small engines can give me some ideas. I have a Toro push mower with a 725 series motor. It worked fine up until two weeks ago. It wouldn't start just back fire. I cleaned the air filter and plug. The mower started after that and ran fine while I cut the grass. Later in the week I cut the grass again without issue. I went to cut the grass again last night and the mower won't start, it will backfire after every 2-3 pulls.

I have spark.
I cleaned the carb and everything looks in order.
The plug and clean and dry.
I pulled the fly wheel the key is not sheared.

Any thing else I can check?

Thanks

 

maybe check compression. but sometimes take the bowl off the bottom and the jet will have something plugging it up. Is it strong spark?

 

oh also check if you have oil, sometimes you may have a low oil sensor and it wont let it start or that sensor goes bad IF it has one.

 

Potential heat coil going out. Happened to my Briggs and Stratton motor

 

Oil is good. I guess the spark is good. I used a spark tester from harbor freight and it was lighting up orange when i pulled the cord. I need to double check the spark plug on the block.

What is the heat coil?

 

It is. It is approx 4 years old.

 

I just tried to look up heat coil and I’m thinking either I’m miss remembering OR the guy meant ignition coil????? I’m no small engine mechanic so someone else please feel free to chime in.

The guy told me that 1 of 2 heat coils was going bad???? They replaced it and it worked.

YouTube may help also. Just glancing I saw a toro mower start problems video title

 

Usually only has one ignition coil and they do go bad.

 

Maybe try there next???? Or at least check out some YouTube videos

 

did you hit anything with the mower or did it just quit?

 

I think most say needs at least 100psi compression.

 

I have no way to check the compression.

I have not hit anything major. When I pulled the fly wheel the key looked brand new.

I checked for spark at the plug and I have it there. Not sure how "good" it is, but there is spark. So I assume the spark plug and megneto are both good.

 

I'm ready to move on from this mower anyways. It has never mulched well and some times the rear wheels lock up when pulling it backwards. I had always had Honda mowers and they were great. Figured I'd try something different with the Toro and regret not getting a Honda.

 

needle valve or float sticking in carb maybe