G1800 blowing 10A fuse

[dthomas]

I have a beloved G1800S with about 1230hrs. It has started blowing the 10A fuse. It has a new wiring harness so no wiring issues, I also replaced the dashboard. Both of these projects were done earlier this year also. I replaced the Combination box back in the spring. I also bypassed the seat switch a few years ago because I put on an aftermarket seat and the shut off solenoid is disconnected and I put a pull lever on to shut off fuel. I also replaced the fuel level sensor 3 or 4 years ago and it seems to work just fine. Since the fuse started blowing and there doesn't seem to be any issue with wires or supply voltages, replaced the voltage regulator which made no difference. I also replaced the fuel lift pump but it makes no difference.

What I haven't replaced is the generator but I am a leaning towards it is not the problem because the battery charging seems to work just fine. I can sometimes mow for a few hours and no issue but lately it has started to blow sooner usually withing 5 minutes of starting up. But it still is a very intermittent problem blowing in a few minutes to about 30 minutes.

Just curious if anyone has had this issue what they found as the cause. I'm pulling what little hair I have left out trying to find what the cause of this is.

 

[GreensvilleJay]

Any chance you can post the original wiring diagram ?
Obviously you've modified it a tad.....

 

[dthomas]

This is the only diagram I have it is not really good resolution. The only mod really is the seat switch and I wouldn't call it a mod I just made a jumper for the seat safety switch plug to trick the combo box into the switch being in the closed position. The fuel shut off valve is just unplugged, it actually tries to work but doesn't always hold the valve off well enough to shut down the engine after the key switch is turned to the off position. None of these would explain the fuse blowing.

When the fuse blows all the gauges stop, the fuel lift pump stops and the combo box won't allow the starter to engage. I replace the fuse and engage the key and all seems happy. I can start it and let it run for an hour and it won't blow the switch. So my guess is something is getting banged around and there may be an intermittent short. I don't really like that idea because if you immediately stop and replace the fuse it goes back to functioning correctly and can be fine for another 5 minutes to a few hours.

NEW UPDATE: Well I noticed the battery retainer bolt on side had broke. Wasn't obvious just look at it as it was sitting the right position when stopped with the bonnet up. However when I was moving the wires around I noticed the battery moved a lot and more than enough to strike the air cleaner case an inch above it. This might explain why it would sit an idle for over an hour and never blow the fuse and only blow it while driving it ... time will tell I guess

 

[dthomas]

Newer update: I noticed it would idle outside the barn for an hour and never blow the fuse. So it must be when it is driving, I drove it for about 30 minutes no blown fuse. So I engaged the blade and it mowed about 40 ft. and blew the fuse. So I unhooked the pto switch and but a jumper between the wires going to the combo box and proceeded to mow 2 acres with out blowing the fuse. I pulled the switch out if i tap on it one of the leads shorts to the case of the switch so that is why it was shorting to ground and blowing the fuse.

The culprit was the PTO switch, it is original the mower, my Dad bought the mower with 28 hrs on it in 1993 from an auction in Tennessee and later sold it to me in 2000. The date code on it shows it was manufactured in 1990 and was sent to a Canadian dealer. I have wondered for the past 24 years how it made its way to Tennessee from Canada in such a short period of time.

 

[dragfan66]

I'm glad you found your problem without replacing a bunch more parts that you don't really need.

 

[dthomas]

Yes me too... I really hate throwing parts at a problem but this thing was so intermittent when it would blow that it was very difficult to trouble shoot. Also every time it did blow when I would replace it it would be fine for 5 minutes to up to an hour or so. Really frustrating to chase down a gremlin like this. I didn't mine replacing the regulator since it was the original. The fuel pump wasn't a real issue since I keep a spare as I have replaced it a few times over the years. One piece of experience on that fuel pump is I bought a kubota part back 10 years ago and it lasted for less than 5 years, I replaced it with an Amazon part and it is still working just fine. I put the new spare on it to see if it good be the issue but kept the one on it as a back up when/if this one fails. The amazon ones are a fraction of the cost and seem to hold up as well as the original and look identical.

Also I replaced the dashboard and wiring harness because they had given up the ghost and were causing a lot of issues the key-on bulb and the heater bulb wouldn't work properly because the pcb material had cracked. The wiring harness all the plugs had become brittle and broken which was causing odd issues from time to time. I found an OEM wiring harness at an equipment auction that fit it and bought it for $80 which was a fraction of the cost of a new one which is no longer available thru Kubota. So I figured that was a good investment in keeping her running as expected.

Since it is 33 years old and going strong I figure the parts are a good investment.