Failing solenoid?

What are the signs of a failing solenoid? My 706 gasser (with new ignition switch) sometimes starts
with the button and sometimes I have to start it with a screwdriver. Could it be a bad solenoid?

Weak solenoid or a sticky bendix are the most likely culprits.

YES it could be a bad solenoid......

HOWEVER the start switch could be bad if it fails to send hot voltage down to the solenoids small activation terminal ??????? Or its wiring may be bad ???

If your JUMP consists of jumping 12 volts to the solenoids small activation terminal (where wire down from start button goes) and that makes it start, the solenoid sounds okay but the push switch or its wiring or a connection may be at fault

If you jump consists of direct jumping (high current big post to starter) from the big post where the battery cable attaches to the starters big input terminal (Output from solenoid) and that makes it crank even if there's hot voltage present on the solenoids small input, SOUNDS LIKE A BAD SOLENOID

Pushing the start sends hot voltage down to the solenoids small activation terminal YOU HAVE TO SEE IF THATS PRESENT WHEN SWITCH DEPRESSED ??? Is it ?? If so the solenoid may be bad......If pushing the start does NOT send hot voltage to the solenoids small input THE SWITCH OR ITS WIRING OR A CONNECTION MAY BE BAD

Other possible causes even if switch and solenoid is okay is a bad terminal or connection or a bad ground !!!

John T

Farmall or International, gas or diesel?

Does your tractor have a pushbutton for starting (as manay IH's do), these can be troublesome/intermittent, and you don't mention replacing it.

Is the safety starting switch at the clutch pedal present and functioning (or has it been ''hotwired'' around)?



https://cdn.compknowhow.com/carterandgruenewald/wiring_diagrams/IH 06 SERIES.pdf

Link to 706m wiring diagrams.

It also has a new rubber button in addition to key switch. I think I jump it from the big bolt/nut to the little nut. It fires right up..always have parking brake on, (before I get a lecture)

Has a new rubber button also new switch

I think I jump it from the big bolt/nut to the little nut. It fires right up.

While I can't be sure from here, that sounds like you're activating the solenoids small activation terminal which duplicates what should happen when the start switch is pushed ???? IE sends voltage from switch to the solenoids small activation terminal

If so that means the solenoid itself is okay so the problem is the wiring or a bad connection or the start switch or the voltage to the start switch (from key switch???) is at fault orrrrrrrrrrr the key switch is bad and not sending voltage to the start switch input ????????

John T

On Delco starter solenoid the large battery bolt head wears away inside over time, then the large contact washer inside can't connect BOTH large bolt heads as needed to engage starter. If the push button switch and safety switch are OK, solenoid can USUALLY be repaired by removing all wires and cable from the bolt, loosen the thin nut, then push in bolt and give it 1/2 turn and pull back out. This will place the good side of the bolt head in place for the contact washer IF bolt has not been turned before. Tighten the thin nut, replace all wires and cable. I've saved a lot of otherwise bad solenoids this way without replacing them, and the bolt can usually be turned without removing starter from engine.

I feel you may need more details on clutch safety
switch. If it has one as it should, it will be down under
the platform by the clutch pedal. You will have to
determine if the switch is making proper contact to
pass the power down to the solenoid. This may easily
be done by building a short jumper wire with two flat
spade connectors on it. Plug that in to see if it
consistently starts by the button. If it does then it is
very likely the switch is not contacting properly and
needs replaced. It is also a possibility that it is simply
not adjusted properly. Please do not fall to the
temptation of just using the jumper wire and not
replacing the switch. I am attaching a switch as an
example.
706 clutch safety switch

(quoted from post at 18:13:32 04/16/23) I think I jump it from the big bolt/nut to the little nut. It fires right up.

While I can't be sure from here, that sounds like you're activating the solenoids small activation terminal which duplicates what should happen when the start switch is pushed ???? IE sends voltage from switch to the solenoids small activation terminal

If so that means the solenoid itself is okay so the problem is the wiring or a bad connection or the start switch or the voltage to the start switch (from key switch???) is at fault orrrrrrrrrrr the key switch is bad and not sending voltage to the start switch input ????????

John T

Click to expand...

ith Wore out & John T.....follow all the wiring from BATT to solenoid small terminal on diagram wore out linked to.

If the solenoid works when you short it with the screwdriver then Id say the solenoid is working and its between push button switch and the wiring to the solenoid . By using the screwdriver and it starts that means the solenoid is doing its job . If it doesnt start every time with the screwdriver then you have solenoid problems

Sounds like a bad connection in the harness. Our 574 did that would not start at the key switch would short just fine. I cleaned and shined and to no avail. I just ran a wire from the switch down to the starter terminal works fine now.

X2 This worked on my 49 Pontiac. Still have the new one in a box.

My chinese tractor is like that too. I just use a screwdriver to jump it. I like it that way.