Interpreting voltage drop tests

[38racing]

I think I solved the problem but wondering if what I saw makes sense. I inherited a rider with a briggs 281707 on it. Person says his tenant was screwing about on it. Found a loose starter and actually insulator around terminal was broken. Maybe tenant broke or took original and threw on the broken. I replaced with a starter from my collection which bench tested ok. Brand new high CA battery but I had issue of no crank. Thought it was the solenoid so I replaced with another used one and cleaned up the ground lead and battery leads and got it cranking and starting. I used it a few times and then a lady was interested in buying. Delivery got delayed as per my other thread about tubing the tire. Used it once again myself. So I loaded it on my trailer (slight hint of not perfect crank when I loaded it but it did start). Then it sat on the trailer for a couple days before I delivered it. I rolled it off and then went to start and it was a short slow crank and then click and hum (from solenoid in my opinion). Winched it back on the trailer and hauled it home. Battery voltage fine and load test fine. Pulled out my guideline for voltage drop which says should be .100 or lower. So on the ground side I get .9. Then on positive side I get .9 to the solenoid input from battery . But I know those contacts and cable are good. On output terminal drop is a bit higher and the same as starter post. I decided it was easier to put on another starter than solenoid (bolt locations). I just used another one that bench tested. It certainly solved the problem. Just wondering if those reading were consistent with a bad starter. I had thought I wouldn't see the large drop until the starter post if it was the starter. And guess what duh! I didn't even think of redoing the tests until a day or two after I took the mower back to the buyer.

[KE4AVB]

Oh my we got one with x-ray vision...Anyway unless you actually got x-ray vision how do you positively know the used solenoid contacts are not burned.

Seriously if you got intermittent problems it is a lot harder to know sure unless you re-test after the changes to see if there are any changes.

Last year I had a Craftsman mower with multiple bad connections. First one would only drop out under load. It turned out to be internal corroded battery cable terminal at the solenoid. It was however doing a nearly complete drop out with near full battery voltage across from the positive post to the solenoid post. It was very strange as even when it dropped out the fuel solenoid would not drop out. Six months later a bad solenoid trigger ground wire showed up too.

[38racing]

I didn't rule out the solenoid. I simply decided to change the part that was easiest to do on this unit.

[Arkie]

If you took it to the buyer and have not get a call complaint you most likey got er dun.

If you get a call I would probably take another battery and a set of jumper cables.
(I've got all kinds of electrical testers but find that I usually just start jumpering things out using a good HEAVY duty set of jumper cables,
BUT before last winter I bought one of the jump and start battery packs on sale with free shipping from tooltopia
this one
Clore
Jump-N-Carry 1700 Peak Amp 12 Volt Jump Starter

and it's really user friendly being portable for starting/checking small engines that does not even have a on board battery or has a old weak battery, large tractors or eq that have not been started in awhile, lots easier than using jumper cables from a vec's battery.
and especially in cold weather using as helper boost starter. Weighs about 25-30lbs and has a built in charger.
Really user friendly for checking things such as you describe also.
But intermittent/erratic crank start issues are not easy to isolate sometimes, no problems at the time you are testing, but when at the new owner the problems re-surfaces quite often.

I've not had any experience with the smaller more portable lighter weight battery booster packs that will charge from a USB connection.

[38racing]

Funny thing. I have both a hand winch and a 12v winch on my trailer. I use a small booster pack to operate the 12v winch. Since I wasn't planning on bringing it back home I didn't have the power pack. Used hand winch. But then I went out yesterday actually expecting to load a rider and forgot the power pack. Turned out the guy hadn't left it out as expected.