520H 25 amp Fuse

[Jbones 10]

Hi everyone, I am a long time viewer of this excellent community and I have learned so much from all of you guys that share your knowledge. I bought a new house and started looking at machines that could clear a long driveway and I stumbled across the 520H with a blower and a 48" deck. Anyway I love it, but now I have an electrical issue I keep blowing the 25 amp fuse. Its a 1992 and if i replace the fuse it runs fine for a while. I can change the fuse and it starts right up and goes fine, is there anywhere I should start looking that is a known trouble spot? 

 

Thanks,

Josh

 

 

 

[8ntruck 7,395]

 to the forum.  Bunch of good folks here.  I'm sure somebody else has experienced and fixed this issue.  So someone will be along with suggestions.

 

To me, it sounds like you have an intermittent short - a tough thing to find.

 

You could inspect the wire harness for damage, thin spots, sections with bare wire, etc. Your machine is almost 30 years old.  Heat and vibration can take their toll on the wire insulation.

 

Good luck and have fun.

Edited August 23, 2021 by 8ntruck

[nyquil junkie 225]

I have 2 520H's and I had no idea they had a 25amp fuse.

 

 

[roadapples 6,983]

They have a 15, 25, and 30. Those fuse blocks are known for problems. You can get a replacement....

[Ed Kennell 40,546]

Look for hot spots, discolored connectors.   The 9 pin ivory colored connector is notorious for overheating and causing shorts.

[Ed Kennell 40,546]

Oh,  to the  Bones.

[roadapples 6,983]

3 minutes ago, Ed Kennell said:

Oh,  to the  Bones.

[lynnmor 7,577]

Be sure that the fuses are in the correct order, front to back is: empty, 15, 20, 25.

Check battery cable connections so that the small wires don't carry too much current.

[peter lena 9,093]

@Jbones, referring to others above , go from that fuse point and track that wire for chafing or a wear spot , causing your short . I  have a  set of  small alligator  wire clip test wires so I can jump  from start to finish on a wiring issue . helping me quickly jump over the problem , agree with others on those multiple connector issues , replace the one that the fuse wire goes to . good luck , pete

[gwest_ca-(File Mod) 11,254]

The 15 amp fuse is not blowing so concentrate on everything powered by the I terminal on the ignition switch.

 

Garry

[squonk 42,591]

The seat switch is in that 25A fuse circuit. first place I would look are the wires going to and from that switch front to back. It's a long run and the wires pass through many spots and could be pinched some where. Even if the switch is disconnected the wires are still there.

[953 nut 58,024]

11 hours ago, Jbones said:

if i replace the fuse it runs fine for a while.

Any electrical connection that is corroded or is not tight will draw an excessive amount of current and could be the problem.  As @squonk said, need to inspect wires for shorts too.  

[WheelHorse520H 708]

Looks like I’m late to the party but it seems like you have a couple of things to check out. I’m following along Incas something happens to my 520.

[Jbones 10]

Thanks everyone, I have a bunch of starting points now. My seat switch is disconnected, I am pretty sure it just has a bare jumper wire in it disabling the seat safety.  If that's part of the 25 amp circuit and the bare wire is hitting the frame I could have a simple easy fix, I will check there first. I just printed the wiring diagram and I will be using that and tracing the circuit if it keeps blowing. 

[953 nut 58,024]

19 hours ago, Jbones said:

If that's part of the 25 amp circuit and the bare wire is hitting the frame I could have a simple easy fix,

In most cases the 25 amp fuse IS in line through the ignition switch to the seat switch. I think you have found the culprit.   

[Paul Dietrich 19]

I also was blowing the 30 amp. fuse, turned out to be the wire going to the seat switch. The little clip that holds the wire in place under the seat pinched the wire.....

[Chuck14025 9]

1974 C120 Running Very Hot,

The fan is blowing a good stream of air across the engine. Has an Autolite 216 spark plug. Running high RPM when mowing so its not being lugged. Suggestions? Questions?

Thanks for looking.

 

 

[8ntruck 7,395]

3 hours ago, Chuck14025 said:

1974 C120 Running Very Hot,

The fan is blowing a good stream of air across the engine. Has an Autolite 216 spark plug. Running high RPM when mowing so its not being lugged. Suggestions? Questions?

Thanks for looking.

 

 

You might want to start another thread here, as this is off topic from the original post.  You would probably get more answers, too.

 

As far as your engine running hot, I have the following suggestions:

 

Make sure your engine tins are are not clogged and that the cooling fins on the cylinder are clean.  Your carb might be running lean.  Your muffler might be partially clogged by a rusted baffle that broke off inside.

 

Good luck.

[Chuck14025 9]

Thanks 8ntruck.  My error on the post. I'll try again. Thanks for the suggestions.

[Lagersolut 723]

I have a 1982 416-8 yesterday started having the same issue - blowing the main 25a right off the solenoid . I'll be following along .

[Lagersolut 723]

Found mine - Seat switch is bypassed - zip tie broke - wire fell on input pulley 

[Handy Don 13,340]

1 hour ago, Lagersolut said:

Found mine - Seat switch is bypassed - zip tie broke - wire fell on input pulley 

 

Noticing the solder/splice there. I've become a fan of those now that I have a suitable heat gun! Quick, clean, and pretty watertight.

[Jbones 10]

Wow I am glad my problem is helping others. I have cleaned up my seat switch safety jumper and I have not blown the 25 amp fuse yet. We will see....... Thanks for all of your help. 

[Lagersolut 723]

1 hour ago, Handy Don said:

Noticing the solder/splice there. I've become a fan of those now that I have a suitable heat gun! Quick, clean, and pretty watertight.

The heat gun is the trick - for years I was using a light touch with a torch on my shrink tubes/butt connectors - solder style burn before the solder melts with a torch . Amazed how many uses I found for my heat gun after I finally spent the money for one . 

[Moparfanforever 874]

When i got my 520 I was reading on here about the fuse block and 9 pin connector problems , so I took the fuses out and took some contact cleaner and compressed air and hosed it down and blew it out. VERY dirty and crusty and things were turning green. Used dielectric grease when I put the fuses back in.

 

The 9 pin connector looked good , but I did the same thing to it as I did the fuse block.

 

Just trying to ward off any gremlins that would pop up in the future.