We have a Farmall 706 gas that we are having some starting issues on. We have replaced the starter and solenoid, a new key switch has been installed, a new starter button has been installed on the dash, brand new battery has been installed, and the clutch safety sensor has been bypassed.

What happens is the tractor won't start. Usually this occures when it is hot. It won't even turn it over. You turn the key, hit the button, and sometimes it will click and sometimes it will do nothing. When it does click, it acts like a dead battery. However, if you take a screwdriver and cross the starter, it'll spin like nothing and fire right up.

So there is something between the dash and the starter. We have already done the above, does anyone have any other suggestions? Does the starter wiring go through the light switch assembly as well? We've noticed that switch may need to be replaced also because of years of corrosion. Just curious if you guys have any suggestions.

Well i would start at the battery and make sure that the terminals are clean and TIGHT and check the ground cable where it is bolted to the chassie , then i would make sure that the battery cable to the starter is tight at the starter . AND maybe replace the solenoid as it may be that the contacts are worn enough that this is the problem . Now as to the clutch safty switch FIX IT as your life depends on it and if i was working on that tractor it would NOT LEAVE unless it was

I agree with the Vet. Clean the connections. If still intermittant, the following test will determine the repair. Put it in neutral,lock brakes.
pull (or unbolt) the start terminal (small) that connects to the push button. Now use a jumper to connect the cable terminal from the bat, to that terminal. If it cranks correctly the wire, or button circuit is faulty. If it is still flaky or does not work, jump across the bat cable to the starter motor input connector. Heavy current, jumper cable, or better. If it now spins, it is the relay/solenoid. JimN

The first step is to buy a voltmeter. I bought one at Harbor Freight for $4.00 last week. The next step is to go to the Restoration forum where CNKS has just posted a wiring diagam for the 706.

1) Hook the voltmeter across the brightened terminals of the battery(not the cables, but the terminals) 2)Crank the tractor and read the voltage. It must not drop below 10 and1/2 volts. If it doesn't charge battery and try again. If it fails again replace battery.

Assuming negative ground: Put positive lead of meter on center of positive battery terminal and negative lead on solenoid terminal where battery terminal attaches. 1)While cranking the voltage lost between the battery should be 1/2 volt or less. If not replace with quality cable.

Now place the positive lead of meter on a brightened spot of starter case and the negative lead on the center of the negative battery terminal. While CRANKING the voltage must not drop below 1/2 volt If it does clean the metal between starter and block and clean the battery cable both where it attaches to the block and the negative terminal of the battery. If it fails again replace with a quality cable. While doing these tests unhook the coil primary so the engine doesn't start. Another test is to hook the positive terminal of the meter to the big battery terminal of the solenoid and the big starter terminal of the solenoid and you will have 12 volts at rest, but should have less than 1/2 while cranking. If not replace the solenoid.

Now we are ready for the control circuit where I expect your problem lies since it cranked while bypassing the control circuit. The light switch is not involved according to the diagram. 1) Put the positive lead of the meter on the little S terminal of the solenoid which is hooked to the push button switch. Hook the other lead of the meter to ground and turn the key on and push the switch and you must read 10 volts or more. If you don't you need to keep backing upstream with the positive lead of the meter until you find good voltage while cranking. Where the voltage is lost is your problem.

For a quick test when the tractor is hot and won't crank do this: 1) Hook the meter across the center of the battery terminals and it must read 12 volts then try to crank and it must read over 10 and 1/2 volts. This verifies it is not the battery. Now take a jumper wire you have taken with you with alligator clips on it and being sure the tractor is in PARK clip one end of the wire to the positive terminal of the battery and the other end to the little S terminal of the Solenoid. If it now cranks you don't need to worry about the earlier cable tests as you have bypassed the push button switch, the key switch and their inherent wiring.

My e-mail is [email protected] and my phone # is 918 627 3317. Let me know where you found the problem.