Lawn mower wont re-start after running for a few min. (craftsman push mower)

My Grandmother has a craftsman 6.75hp push mower. Model number 917.376571. She called me complaining that it wouldnt start. She has cleaned the air filter and the spark plug. This mower has a "sure start" type cap which has a fluid in it to help the mower start even if it has stale gas. She's replaced that since it was empty and also used the mower all year so we know the gas is fine. I brought the mower back to my house and low and behold, the first pull and it starts right up. I let it run for about 30 seconds and shut it down. Wait about 10 seconds and try again with no start. I gave it a whirl about 5 times with nothing. I took the carb off and cleaned it real good with carb cleaner and also whiped up any other gunk I could see around moving parts. Put it back together and it starts up just fine. I cut it back off and try again with the same results as the first time. The spark plug seems to be firing correctly, the carb seems to be working fine, no problem with fuel or the air filter. The motor isnt getting up to operating temp but that souldnt matter. Any suggestions on what to try next? Thanks folks!

 

Does this engine have a primer on it, or the automatic choke?

 

It's an auto. Just hold the handle and pull the cord. I actually tried to start it a couple of more times last night after letting it sit for a few hours and nothing. Wouldnt start. I will try again today. When I got it to start the first time, it had been sitting for atleast a full day with no start attempts and of course the next time it started was when I took the carb off and cleaned it.

 

The automatic choke is most likely the problem. You'll have to gain access to it and see what is happening. I've seen problems with them... I think I recall a part being popped out of place near the exhaust where the choke control is located, and seems like I've seen one or two with a problem near the vane. Vague, I know, but I don't recall the details. I don't work on that many of this type choke system to recall details.

 

FIXED! After messing with it for quite sometime, it was the kill switch that's attached to the handle that you hold down to start. Somehow when you pull the handle, it wasnt comming off of the metal tab like it was supposed to. It was always making contact, in turn making the spark plug not fire. I found this out by taking the spark plug out (still connected to plug wire), grounding it to the motor with a wire and pulling the cord. I saw no spark so I figured it was something electrical. I have no idea how it started twice yesterday but I made a small adjustment to the cable and bent the tab a little so it makes contact when you let off but barely doesnt when it's pulled in. Now it's running like a champ. Started 3 times in a row and twice again when I tried after dinner. Thanks for the help and responses Cheese. This was my first post and I look forward to visiting this site for all my home projects and problems that may arise.

 

Great! Glad you got it fixed! I guess the fact that it was doing it only after it already cranked up once was just coincidence, or something was stretching/flexing out of shape the first time you used it? Anyway, glad you got it and thanks for the update.

 

I had the same problem. The mower would run fine and then just stop,sometimes it would complete the job and then not start. Once i blamed it on the gas so i changed out the gas and it ran fine. Then a few weeks later it would not start! Anyway i did the same things you did and after taking of the cover off i found the kill assy. to be dirty and a hair out of adjustment that was keeping it from starting. I wonder how many mowers have gone to the shop at $80.00 min. a pop with this condition?

 

Can you please place a picture for help?

>>>>> FYI

 

I don't care how old this thread is. If someone could get a picture of the kill switch it would be GREATLY appreciated! Thanks ahead of time!