Testing Starter on Branson 3520H - Need confirmation that I'm doing it correctly.

gwisejr · Mar 12, 2021

Morning,

Yesterday after about 4 hours use, the tractor will no longer start up after it was shut down for a few minutes. I've checked the battery and confirmed that it appears to be good along with verifying a solid ground. When the key is turned to the A position to warm up the glow plugs, I do hear the clicking of solenoids. When I turn the key to the crank position, I hear additional clicks under the console. I've confirmed that I have +12v at the large terminal with the red rubber cap and Ground at the other large terminal with the black rubber cap on the starter. The smaller terminal shows a ground until the key is turned to the crank position and then it shows +12v..

In my attempt to test the starter, I disconnected the small terminal lead and connected a jumper from the battery +pos terminal to that small terminal on the starter. nothing happened. I am under the assumption that the starter should have cranked the engine and failing to do this, the starter is the problem..

Can any one confirm this conclusion and if possible, provide any additional testing?

PS. The no start condition happened a week ago. Same thing, I was using the tractor on and off to move brush piles. It would not crank. I move the PTO selection lever, not sure if moved it to neutral or to the lower setting and it started. I did check the underside for any branches, etc that might have gotten caught and found no issues.. Plus, I normally the PTO in the low setting with the PTO on/off switch Off and it has always started for me. I'm not clear on what all safety switches there might be but I'm assuming that it passes those safety switches since the starter lead to the starter goes +12 when i turn the key to the crank position.

PSS. Just talked to the Branson dealer, they only sell the whole starter ($450) and not just the solenoid. Does anyone know if that solenoid can be tested separately and if so, where I can get a replacement if it turns out to be the issue?

Thank You..

George Wise

med that the starter lead

Roadworthy · Mar 12, 2021

Put all your wires back to their original locations and tighten securely. Put your voltmeter on the battery to confirm it's at voltage - nominally about 12.6 volts. While watching the voltmeter have somebody try to start the tractor. The voltage will probably drop somewhat but probably should stay above eleven. This load test will tell you if the battery is up to the job. If the battery passes this test move to the big terminal on the starter. Have your helper try again to crank the tractor while you observe whether the starter is actually getting full voltage or close to it. This will confirm the wiring and the solenoid are doing their respective jobs.

gwisejr · Mar 12, 2021

Roadworthy, thanks for the response. So normal batt voltage is around 12.65. Measuring from the battery while at first position takes it down to about 12.3v and cranking goes down to 11.8v. About the same measurements from the positive terminal on the starter motor.

ptsg · Mar 12, 2021

No sure if it was mentioned or not but check your ground to the chassis. Most times it is the cause for all kinds of random electrical issues.

CoyPatton · Mar 12, 2021

As I understand what you did, you disconnected the wire from your starter switch that connect to your solenoid on your starter. You then jumped from the battery cable connection on your starter to to the terminal on your starter where the switch connects.
If this understanding is correct, assuming your battery cable connections (ground and positive) are in good shape, then you have issues with your starter solenoid.
Unfortunately, I can not tell you if you can replace just a solenoid on your tractor. Hopefully someone else will chime in to give you that info.
Again prior to removing/buying a starter, check all wiring connections closely. Typically, although I am not sure on a Branson, if you have 12 volts from the ignition switch to the starter solenoid your safety switches are not the issue.

Dave M7040 · Mar 12, 2021

The starter relies on contact with the engine block for its electrical ground.

There have been cases with older tractors where the mating surfaces are too rusty to provide a ground path.

Simple test is to run a battery jumper cable from the battery negative post to the starter frame or mounting bolt.

Dave M7040

gwisejr · Mar 13, 2021

Update:
Tractor finally started.. I had completely cleaned the battery terminals. I inspected the ground connection to the frame, actually to the engine block and it looked clean.. At this point it still would not start..

I then attempted to remove the starter motor so that I could take a closer look at the solenoid. I had disconnected all the terminals which I had already done previously.. I was not able to completely remove the starter motor, there is just not enough space to get it off the mounting screws. Looks like you have to either remove the hydraulic pump or remove the low pressure hydraulic supply line. Anyways, after 30 min of trying every combinations I could envision, I put it back on. settled on waiting till Monday for the dealer I purchased it from to check with Branson about the warrantee. a couple hour later, got my son to help me do one more test of the solenoid. I wanted to confirm that once I the key is turned to the cranking position, that there is a lower resistance between the Pos + and Neg - terminals of the solenoid. Low and behold to my surprise, it started..

Thinking about Dave's comment about ths starters contact with the engine block, I don't recall seeing any significant corrosion between the two. Looked pretty clean to me.. I did notice that the ground connection on the solenoid has a link that goes directly into the body of the starter motor. I could not turn it enough to get a good look at it but it is not a wire that I could disconnect and goes right into the starter motor thru a rubber grommet. I wonder now if just twisting that starter around temporarily cleared the issue.

I'd appreciate any comment from anyone that is familiar with these Branson engines. I'd hate to think that the trouble is resolved then have it happen again after the warrantee period expires..

Thanks.

LittleBill21 · Mar 13, 2021

google voltage drop test, this will show you if the wire connections are bad. you can also jump the starter bypassing the solenoid simply by clamping jumpers on the large post, not the small one, if it reliably starts doing this, its points to the solenoid

gwisejr · Mar 13, 2021

Hm, LittleBill21, explain a little more please. As I understand it, the starter solenoid is really just a high current relay.. you cant bypass it without removing it and getting directly to the Starter positive lead. The Large Positive terminal on the solenoid already has 12+ bat voltage on it. The smaller terminal is grounded until the key is in the crank position and then it give is the battery 12+ voltage with then activates an electromagnet in the solenoid that connects the main 12 +V to the starter motor..

I had already tried jumping the smaller solenoid terminal to 12+ with no results.. that is why I thought that is was an issue with either the solenoid or the starter motor..

Topzide · Mar 13, 2021

9 out of 10 it's the solenoid or bad ground. Unless you swamped the starter or excessive cranking, the main starter motors are pretty tuff. I think all the wrangling you did with starter cleaned the ground contact against the block.