B7800 blowing 5A start/stop fuse, solenoid ok

[Ray7800]

Good morning and thanks for all of the support in these pages.

Short version - while driving the tractor to a neighbor the engine stalled. The starter wouldn't engage and when jumping the terminal posts it would roll over and the tractor wouldn't start. Upon inspecting the fuses, the 5A was blown. Replacing it and turning the key blows another. Disconnecting the "fuel shutoff" solenoid and the fuse stopped blowing, so I replaced the solenoid (silly me, $152 later) and the problem persists. I am looking for a wiring diagram and while I search I thought I would rely on your expertise.

BTW - it runs with the fuel shutoff solenoid removed & disconnect, starter operates, etc. Everything normal (except shutdown means you depress the plunger).

Thanks everyone!

Ray
B7800 with a few cool attachments.

 

[N3BP]

You might want to double check the manual on fuse size. 5A seems small for solenoid.

 

[Edke6bnl]

this is some talk on fuel shutoff solenoid that might help that I save for my B7800

 

[GreensvilleJay]

curious, so I just downloaded the op man from kubotabooks.
5A is correct rating/value/size for fuse
I don't have wiring diagram but..

question. is there ANYTHING else connected to that 5A fuse ?

also, disconnect solenoid and use ohmmeter to measure it's resistance. be sure to subtract 'zeroed test leads' value.

 

[Ray7800]

You might want to double check the manual on fuse size. 5A seems small for solenoid.

I did verify, I also tried a larger fuse so I am convinced that somewhere in the circuit is a short or draw abnormally high

 

[Ray7800]

So, I am headed out to measure the resistance of the solenoid coil (both the original and new) and will report back. I think the fuse on the diagram below - just above "2" (key stop solenoid) only feeds two components. My little brain is saying if I replaced & verify "3" then it must be "2" and that seems more challenging to access. BOTH measure 16.2 ohms ***

I don't think there can be much more - except a chewed wire as opposed to a faulty component

 

[GreensvilleJay]

hmm.. somehow when you connect the stop solenoid, it's shorting the +12 'feed' to ground since the 5A fuse ONLY blows when it's connected.

If solenoid read 16 ohms, it's 'good' should only draw about 1 amp of current so won't blow 5A fuse.

it is a bit of a puzzler so carefully inspect that wiring. A picture of two might help.