Blowing fuse on Craftsman riding mower after startup

[rangerfredbob]

I have a mid '90's Craftsman mower, missing identifying stickers but I have the part number somewhere...

Anyway, should be fairly standard, has safety switches everywhere and electric blade clutch with 3 speed high/low transmission. It will start just fine, but if I let off the clutch it will kill the ignition to the engine, same if I flip the blade clutch switch. This issue is new and didn't happen when it was parked according to the wife... that was a few weeks ago... I got on it a while ago and went through all 3 30A fuses I could find trying different things... In the last year and a half I've replaced the ignition switch and seat switch when they went out. I tried bypassing the seat switch but it arc'd and I think that's what took out the last fuse. I looked for obvious shorts and didn't find anything. There's a bunch of wires going to the PTO switch so I'm wondering if it's shorted internally so I ordered one to show up tomorrow, along with some fuses... Unfortunately it's been stored outside for the last couple years so that isn't ideal, but it's summer, I wouldn't expect that to be an issue now.

Any other ideas? This model has auto headlights that come on with the ignition so that's more amperage than normal, but it all worked until recently... Any chance it's the voltage regulator on the Kohler engine? After the engine is started the amp meter goes one way then evens out after a few seconds when I replace the fuse so I didn't order one of those yet...

 

[Fuddy1952]

I would temporarily replace 30A fuse with a 30A resetable breaker so I could try different things seeing when it trips. Maybe wire insulation worn off somewhere touching ground.

 

[RandyT]

I would be looking for a bare wire possible mouse damage. The dying when brake released or when pto engaged would lean toward a seat switch issue. Could be voltage regulator or fuel solenoid on carb, but I would think if they were shorted it would blow the fuse as soon as the key was turned on. But from your description sounds like the voltage regulator is acting normally. Normally also the seat switch is a ground for the ignition system to kill the engine, there shouldn't be any voltage on that system to arc or even be fused.

 

[jaxs]

I would be looking for a bare wire possible mouse damage. The dying when brake released or when pto engaged would lean toward a seat switch issue. Could be voltage regulator or fuel solenoid on carb, but I would think if they were shorted it would blow the fuse as soon as the key was turned on. But from your description sounds like the voltage regulator is acting normally. Normally also the seat switch is a ground for the ignition system to kill the engine, there shouldn't be any voltage on that system to arc or even be fused.

That's also what jumped out at me. I would start there to see how + voltage found it's way into that circuit.

 

[Roadworthy]

Assuming after sitting all this time you can get the engine started, I'm going to pretend nothing has changed. I have a ten year old Craftsman mower and all the safeties must be satisfied to start the engine. Yours is probably similar. Have you identified two problems or one? You say when you let out the clutch the engine dies. Is it in neutral at this point? Is this the point at which the fuse blows? If I try to move mine before warming up a bit mine will die, too. At this point we have a running engine. If the fuse is not blowing at this point you should probably address why the engine dies when you let out the clutch.

 

[RandyT]

That's also what jumped out at me. I would start there to see how + voltage found it's way into that circuit.

Depending on how it is wired, some mowers have 12 volts through the seat switch that triggers a relay, But on craftsman and such it should just be a kill circuit ground. Battery voltage could be coming from two bare wires touching, a faulty clutch switch, key switch, or pto switch.

 

[CobyRupert]

Symptoms describe what typically happens when someone tries to move tractor or engage blade when the seat switch is not satisfied.
I’d start there.

 

[jaxs]

Symptoms describe what typically happens when someone tries to move tractor or engage blade when the seat switch is not satisfied.
I’d start there.

I hadn't heard that before. For benefit of those who can troubleshoot electrical will you explain where the excess load come's from causing fuse to blow?

 

[tomplum]

Is there a model listed under the seat?

 

[rangerfredbob]

Yes, it starts and runs, if you sit in the seat and push the clutch it will start right up, let off and the safeties kill it, push it in again and it will run, rinse and repeat... same with PTO switch.

The PTO switch I ordered didn't do it, but I changed it anyway, the old ones handle was pretty oxidized...

Whatever is going on is related to the seat switch, the fuse only blows when you short that... It'd be nice if it would have stopped in the driveway or by the shop... I think I'm going to have to pull the rear fenders... I can't think of why there would be voltage going to the seat switch... unless the relay is fried, I think I do have a spare of that...

If it helps it's a 917.258863