Well, Frig. Still have an electrical issue.

[BobRip]

The circuit breaker could be defective and tripping at a lower current than rating.

A wire that is corroding inside will increase resistance and reduce current.

Get a clamp on DC AMP METER and watch the current. This is a must. Forget ohms. You are checking ohms with minimal current. On an erratics problem the ohms is mostly worthless. Get the DC CLAMP ON AMP METER. WATCH CURRENT. Until you do this you know nothing.
Listen, I am an electrical engineer and have been troubleshooting electrical stuff for 60 years. Do what I say here.

 

[Marks481]

Well the good news is that when you are done chasing this down you will have a completely new electrical system....

 

[woodlandfarms]

Spent an hour mowing with no blown breaker. Do I trust I have resolved the issue? no. But that is because I have put around $300 into parts that could be intermittent and have found a $5 part the culprit.

I am getting an amp meter going. I think I have a spare one from my 69 Charger. I don't think my multimeter does amps (well, it does but I think it is only like 10 Amps).

I was reviewing the wiring schematic tonight. On my system it reads

Battery To 50 Amp Fuse to 20 Amp Circuit Breaker to Ignition.

I was adding up the amps I pull, 7 Amps for coils when mowing (Draft, Seat and PTO Solenoid). 7 Amps for cooling fan. Throw in 2 Amps for misc electrical (guages and such) then put on my lights which are 200 watts total (17 amps). I need to look at this wiring. Doesn't seem healthy with the lights on for sure. Didn't help the breaker if it didn't kill it.

Oh, breaker was gunked up for sure. Rust was on the "reed" and it looked like the contact pads were gummed up.

 

[cqaigy2]

Here's some examples for amp meters. You could use a shunt resistor across your meter leads.

Shunt Resistor

 

[Coyote machine]

I'd say do what Bob Rip says and get a DC ampmeter, clamp on type, and solve this problem. Ohm meters are good for tracing continuity, open circuits, etc, but do virtually nothing for amp readings, over-current readings etc.
Or you could continue guessing and replace everything and still not get it right.
There's a method to troubleshooting and so far you've missed it, which is why parts replacement based on guesswork is so futile.

 

[RegL]

Unless you have more trouble, I would stop worrying about it. Pretty sure you had a weak breaker. Not that uncommon.

 

[k0ua]

The circuit breaker could be defective and tripping at a lower current than rating.

A wire that is corroding inside will increase resistance and reduce current.

Get a clamp on DC AMP METER and watch the current. This is a must. Forget ohms. You are checking ohms with minimal current. On an erratics problem the ohms is mostly worthless. Get the DC CLAMP ON AMP METER. WATCH CURRENT. Until you do this you know nothing.
Listen, I am an electrical engineer and have been troubleshooting electrical stuff for 60 years. Do what I say here.

I will back Bob up here, I have only been doing it for about 45 years, but he is telling you the straight stuff.

 

[woodlandfarms]

To the clamp. I am a Fluke sort of guy but the price has been a bit much for this kind of tool and how much I would use it. Got any suggestions for a less expensive, yet useful, version?

Have a full day of mowing and heat tomorrow so will let everyone know. Still don't have my engine temp sensor fixed so don't want to over do it.

 

[SpringHollow]

I managed to get a new Milwaukee Clamp-on 2237-20 on Ebay for $47 delivered. If I need more than 600 Amps, I will just guesstimate by the glow of the fire. Make sure you look for DC amps on the specs. Most clamp-ons I have seen do not do DC amps.

Ken

 

[Coyote machine]

Try googling amp clamp meters:Fluke 325: 400A AC/DC True-rms Clamp Meter with Temperature Or buy a Fluke. If you had one already think how much you would have saved in parts/frustration by now....
What needs to be done to get the engine temp gauge working?