What damage can repeated Jump Starting cause?

[Sparty047]

For the long version of my starter system problem see my previous post!

1) I know there is an issue causing a voltage drop in the current sent to the starter relay harness when the main switch is turned "on". It only measures 10.8V versus the battery's 12.7V which fails to activate the starter relay. I have not been able to localize the source and am frankly frustrated.

2) I can turn on the main switch and easily start the engine by momentarily jumping across the harness to engage the starter.

3) I recall my Father's 1940s era IH basically did this. You set the choke, pulled the "on" switch, and then pulled back on a spring loaded rod to engage the starter motor. When the engine caught you released the rod to break current to the starter motor.

HERE'S MY QUESTION:

What risk of damage do I run if I completely remove the starter relay switch and just add an Engine Start Push Button wired into the starter relay harness? Please be specific in causes of damage.

Thank you.

 

[TheOldHokie]

For the long version of my starter system problem see my previous post!

1) I know there is an issue causing a voltage drop in the current sent to the starter relay harness when the main switch is turned "on". It only measures 10.8V versus the battery's 12.7V which fails to activate the starter relay. I have not been able to localize the source and am frankly frustrated.

2) I can turn on the main switch and easily start the engine by

HERE'S MY QUESTION:

What risk of damage do I run if I completely remove the starter relay switch and just add an Engine Start Push Button wired into the starter relay harness? Please be specific in causes of damage.

Thank you.

None. Is that specific enough?

Dan

 

[lmichael]

You can add a simple helper relay. I did this on mine. Running heavier current though numerous lightweight micro switches in all kind of hidden locations that are exposed to moisture, dirt, vibration, very light gauge wiring, and unprotected connectors is nothing but a PIA recipe for problems. You can keep everything in place, use a helper relay that doesn't need the high current of the starter solenoid. So the helper relay can operate on a fraction of that current, and then locally switch the higher current and voltage necessary to operate the starter. Many machines come from the factory like this. Don't understand why the Kubota doesn't.

 

[TheOldHokie]

You can add a simple helper relay. I did this on mine. Running heavier current though numerous lightweight micro switches in all kind of hidden locations that are exposed to moisture, dirt, vibration, very light gauge wiring, and unprotected connectors is nothing but a PIA recipe for problems. You can keep everything in place, use a helper relay that doesn't need the high current of the starter solenoid. So the helper relay can operate on a fraction of that current, and then locally switch the higher current and voltage necessary to operate the starter. Many machines come from the factory like this. Don't understand why the Kubota doesn't.

I think his starter switch is a direct circuit from battery to solenoid. I have been stsrting a G2160 like that for a couple years now. I tried the "helper" relay and it didnt.

Dan

 

[lmichael]

I think his starter switch is a direct circuit from battery to solenoid. I have been stsrting a G2160 like that for a couple years now. I tried the "helper" relay and it didnt.

Dan

Not sure why it would not help yours. Where/how did you wire it in? Also was it a high enough current capacity? If you look up the posting I did on mine. I have mine wired in right up close to the starter. Everything is soldered and sealed with marine grade shrink tubing. And the relay can operate on voltage as low as 8 volts to "switch" it. I get 10 so it does the trick. The on starter solenoid will not attempt to switch with less than 10.5+ volts

 

[Flintknapper]

None. Is that specific enough?

Dan

Agreed, no risk of damage provided the switch used to replace the solenoid is a 'momentary' switch and can cease sending power to the starter as soon as the engine starts.

The bendix on the starter is spring loaded and will/should retract once power is cut to the starter....so it won't remain engaged to the ring gear on the flywheel.

 

[TheOldHokie]

Not sure why it would not help yours. Where/how did you wire it in? Also was it a high enough current capacity? If you look up the posting I did on mine. I have mine wired in right up close to the starter. Everything is soldered and sealed with marine grade shrink tubing. And the relay can operate on voltage as low as 8 volts to "switch" it. I get 10 so it does the trick. The on starter solenoid will not attempt to switch with less than 10.5+ volts

It was wired correctly. The helper relay simply did not pick any better than the OEM relay. The manual "jumper" works every time. The only "downside" is you lose your starter interlocks which is not costing me a single wink of sleep.

Dan

 

[lmichael]

I bypassed all my interlocks except one (the brake interlock) and mine still would not get enough voltage down there. I could only get 9 to 10 volts. But perfectly fine to fire it up with the relay. And I don't lose any sleep regarding no interlocks. Heck my first real machine was a 1961 Allis and there weren't even any belt guards let alone interlocks. Managed to not do anything stupid

 

[TheOldHokie]

I bypassed all my interlocks except one (the brake interlock) and mine still would not get enough voltage down there. I could only get 9 to 10 volts. But perfectly fine to fire it up with the relay. And I don't lose any sleep regarding no interlocks. Heck my first real machine was a 1961 Allis and there weren't even any belt guards let alone interlocks. Managed to not do anything stupid

I have a 41 Ford 9N and a 51 8N. Both have OEM starter interlocks but its just a mechanical linkage that immobilizes the starter switch when the transmission is in gear - can't depress the button. Reliable and effective. Still plenty of other ways to kill yourself with them.

Dan

 

[lmichael]

I have a 41 Ford 9N and a 51 8N. Both have OEM starter interlocks but its just a mechanical linkage that immobilizes the starter switch when the transmission is in gear - can't depress the button. Reliable and effective. Still plenty of other ways to kill yourself with them.

Dan

Yeah I understand that clutch pedal can do a real number on your shin

 

[North Idaho Wolfman]

What your asking is not "jump starting" it's just bypassing the electrical system.
Why don't you try replacing the starter relay, as that should be the cause of the voltage loss.

 

[GeoHorn]

As long as the switch you DO use is rated sufficiently for the task it should not be a problem.

Are you old enough to remember when to start the ol’ Dodge (or other) you had to simultaneously press your foot on the accelerator and the huge starter-button right-next to the accelerator…?

That was a direct contact-switch to the main battery positive cable.

 

[bird dogger]

As long as the switch you DO use is rated sufficiently for the task it should not be a problem.

Are you old enough to remember when to start the ol’ Dodge (or other) you had to simultaneously press your foot on the accelerator and the huge starter-button right-next to the accelerator…?

That was a direct contact-switch to the main battery positive cable.

Yup, Our first farm trucks had that feature. As kids, we'd have to sit in the truck waiting for the signal to drive under the combine auger so the farmers could unload the hopper on the go. When we were first allowed to help out, we virtually had to stand up and hold onto the steering wheel in order to get both the foot pedal and that switch engaged. Once started, we could sit down on the extra seat padding to allow us to better see over the hood and head for the combine. We were pretty proud truck drivers back then!

 

[Dave_eng]

A few years ago a friend of my son in his late 30's, races Formula Fords so no dummy, had his daily driver car in my shop. He had bypasses the clutch safety switch on his VW thinking he did not need it. I was standing in front of his car and he reached in to turn the engine over. Car was in gear. Starter engaged, car leapt forward and drove me against a heavy work bench. I was fortunate I was still able to walk afterwards.

There have been too many horror stories of owners being run over by their own machines or a run-a-way machine smashing someone or something to think you are going to find someone willing to assume the risk of encouraging you to bypass all the safety features the tractor's designers felt necessary to include.

Most members are willing to work tirelessly with anyone trying to solve a problem. However, the owner (you in this case) needs to be prepared to acquire a quality multimeter and learn how to do voltage drop tests in order to zero in on the cause of the low voltage. These machines are, by comparison to day's trucks and cars, quite simple.

This summer another friend cut the end off a finger, brain fade and a normally cautious guy reached under a rotating 48" mower deck. As safety switches failed, he had been bypassing them.

If you want my help just ask.

Dave

 

[mikester]

You are going to need a high current switch and heavy gauge wires if you are running the switch at your operator station. If you use a relay you don't need all the heavy gauge wire. Heck, why not just fix the OEM relay instead of re-inventing the wheel?

 

[GreensvilleJay]

curious, downloaded the WSM off kubotabooks.....
starter is powered through 40 amp fuse, so a 'pushbutton' good for 60 amps could work fine.

here's one....

https://www.princessauto.com/en/60a-push-button-starter-switch/product/PA0008271090

..so $12 CDN, probably 10 south of the 49th....
this switch bypasses ALL the starter wiring from battery, safeties and the 'starter relay', so it's LIVE all the time, ANY one pressing it WILL engage the starter....

next option, a low current pb switch to feed power to the 'starter relay' (#4 in the 'starter wiring' picture ).
this bypasses the 3 or 4 safety switches and wiring, much safer IF you feed power from the ign switch...
I would like to think the 'starter relay #4' is actually good(easy to test) but if replaced use one rated for 60 amps WITH gold plated or gold/palladium(sp) contacts.

I suspect it's not only 'bad ' switches but that the wires are corroded, ends at switches get wet ,water gets 'wicked' into the core, copper corrodes, increases resistance, less current will flow, low volts at the starter relay. I've seen this corrosion wick go 30-50 FEET in communication cables

 

[TheOldHokie]

curious, downloaded the WSM off kubotabooks.....
starter is powered through 40 amp fuse, so a 'pushbutton' good for 60 amps could work fine.

here's one....

https://www.princessauto.com/en/60a-push-button-starter-switch/product/PA0008271090

..so $12 CDN, probably 10 south of the 49th....
this switch bypasses ALL the starter wiring from battery, safeties and the 'starter relay', so it's LIVE all the time, ANY one pressing it WILL engage the starter....

next option, a low current pb switch to feed power to the 'starter relay' (#4 in the 'starter wiring' picture ).
this bypasses the 3 or 4 safety switches and wiring, much safer IF you feed power from the ign switch...
I would like to think the 'starter relay #4' is actually good(easy to test) but if replaced use one rated for 60 amps WITH gold plated or gold/palladium(sp) contacts.

I suspect it's not only 'bad ' switches but that the wires are corroded, ends at switches get wet ,water gets 'wicked' into the core, copper corrodes, increases resistance, less current will flow, low volts at the starter relay. I've seen this corrosion wick go 30-50 FEET in communication cables

He is not switching motor current, He is switching solenoid coil current which is way less than motor current. The solenoid simply pushes the starter gear out to engage the ring gear then internal contacts within the solenoid close to switch the motor current via a separate dedicated heavy duty circuit.

Dan

 

[SDT]

For the long version of my starter system problem see my previous post!

1) I know there is an issue causing a voltage drop in the current sent to the starter relay harness when the main switch is turned "on". It only measures 10.8V versus the battery's 12.7V which fails to activate the starter relay. I have not been able to localize the source and am frankly frustrated.

2) I can turn on the main switch and easily start the engine by momentarily jumping across the harness to engage the starter.

3) I recall my Father's 1940s era IH basically did this. You set the choke, pulled the "on" switch, and then pulled back on a spring loaded rod to engage the starter motor. When the engine caught you released the rod to break current to the starter motor.

HERE'S MY QUESTION:

What risk of damage do I run if I completely remove the starter relay switch and just add an Engine Start Push Button wired into the starter relay harness? Please be specific in causes of damage.

Thank you.

Repeated jump starting will cause no damage if properly done.

That said, starter motors are intermittent duty and prolonged cranking can and will cause damage.

A cranking motor should not be operated for more than 15-20 seconds without a significant cool down period.

 

[lmichael]

Dad, had a 47 Chevy sedan when I was a kid. I was kinda young but IIRC that big starting pedal did 2 things. It engaged the flywheel and had a large momentary contact switch to turn on the motor. Then he got a REALLY modern car. A 1950 Pontiac. Wonder of wonders it had a little chrome starter button on the dash. Coolest thing ever. Then for years everything was done by the key. Now? We're back to pushing a button. Will wonders never cease? LOL

 

[GreensvilleJay]

according to the diagram in the WSM, page 384, the 'starter relay'( 4) has a 5 amp fuse, the starter has a 40 amp fuse (6). The starter relay contacts feed the 12v to the starter.
So, if he's replacing the starter relay contacts ,he needs a switch that will carry 40 amps.
If he's bypassing allt eh 'safety stuff' and controlling the starter relay coil, then the switch needs to handle 5 amps (rating of fuse (5) ).