Craftsmen lawn mower wont stay running; help!

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snowguy

New member
I have a mid-90's Craftsmen lawn mower (16.5hp B&S with 42in deck). It starts fine but then the engine dies when I let out the clutch or try to engage the mowing deck.

Any thoughts?
 
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Dave_B

Active member
Mechanically speaking, I can't really help but I have the same tractor and I always look for the simple fix first. The only advice I can give is to check the belt tension. I've found on mine that, if it's too tight, it really bogs the motor when engaged which could cause a stall.
 
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mnguy

New member
If it spits and sputters while dying I would clean the carb bowl out (especially if you can save it with the choke). If it shuts off like the key switch was turned off you probably have a safety switch issue.
 
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mnguy

New member
Depending on the mfg and model, the seat switches could be wired normally open or normally closed. On some of the normally closed, there was a tang in the plug that would short both terminals when unplugged (can be a real head scratcher). You can check the seat switch with an ohm meter or continuity tester to see which style you have. From there you can determine whether to jump the wires or seperate them.

The switches can be a pain , but I always think about a customer from my days at the lawn mower shop. Within hours of picking up his new rider, I had to make a service call because the unit wouldn't start. A quick inspection and the problem was obvious...he had tried to bypass the seat switch. While explaining to him the importance of safety switches, he held up a hand that was missing parts of two fingers.....from previous lawn mower accident. Slow learner I guess...but the switches are there for a reason.
 
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Dave_B

Active member
I would not discount the safety switch but, how would engaging the clutch or the mower deck cause an auto shutoff if his butt is firmly planted on the seat and it runs fine prior? I like that as an "easy fix" option to consider but it seems like there has to be something else going on. I'd like to know how this plays out because I have a 1995 version of his machine and have had to make many fixes but this wasn't one of 'em and, I like my fingers where they are!
 
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k_smith

New member
If the seat switch is bad and he were to engage the deck. It would be like you got off the seat with the deck on and shut the lawn mower down. I would check the seat switch and brake switch. If both are good try cleanin your carb
 
lofsfire

lofsfire

Active member
My neighbor had a similar problem with is tractor. as soon as he would turn the mower on it would die. I told him to check that nothing was in the deck. He found about 20' of twine he had ran over at some point raped at the top of his blades. That help but still did not solve the problem. end up he had a safety switch that he had to pull up to be able to put the tractor in reverse with the mower going. the switch was going bad.

So when the tractor had the twine in it, there was a load that shook the tractor enough that made the switch kick on and off. Then after taking the twine out we tested it on the driveway it would work. After going on the grass and hitting a few bumps it would start having problems again. We knew the engine was fine because it would drive and run all day if need be with out the mower turned on with out problems.

Good luck I still don't have my craftsman tractor running right.
 
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mnguy

New member
When in doubt, check the switches with an ohm meter. Like anything else mechanical they wear out. Sometimes they work intermittently for a while before they wear out completely.

An inline spark tester will show bad switches too. With the engine running, if the spark goes away when the mower is engaged or the brake/clutch is let go....it is a switch causing problems.
 
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