DZG 32 #1 Posted October 4, 2022 I got a 78 yardman GT i finally sourced an original style engine for (thanks @Pullstart) and am now trying to figure out a wiring issue. You guys were so helpful with my engine stuff i decided to post more unrelated questions...lol. The key wont start it. It has a ford style starter solenoid but with only one little post. I found a wiring diagram online looks like power goes from key, to a PTO safety switch, then up to the solenoid to tell it to get to work. Im not getting any power at the solenoid wire. I jumped past the safety switch as i had 12v to it, still nothing. So i ran a wire right from the safety switch wire (only hot during cranking), to the solenoid wire. Had 12v at solenoid wire...plugged in solenoid,..nothing. Checked wire...0v. Unplug wire from solenoid...12v Plug into solenoid...0v What is causing that? Bad solenoid? Ground? Electrical isnt my strong suit. Thank you. 1 Share this post Link to post Share on other sites
Pullstart 62,905 #2 Posted October 4, 2022 Dustin, is that switch for a magneto? I’d assume so, since the old machine was a Briggs. The kill should be a ground, right? 2 Share this post Link to post Share on other sites
DZG 32 #3 Posted October 4, 2022 4 minutes ago, Pullstart said: Dustin, is that switch for a magneto? I’d assume so, since the old machine was a Briggs. The kill should be a ground, right? I believe so yes. But the wire in question runs right into the solenoid...i figured it sent 12v to the solenoid to engage it. 2 Share this post Link to post Share on other sites
Pullstart 62,905 #4 Posted October 4, 2022 17 minutes ago, DZG said: So i ran a wire right from the safety switch wire (only hot during cranking), to the solenoid wire. Had 12v at solenoid wire...plugged in solenoid,..nothing. Checked wire...0v. Unplug wire from solenoid...12v Plug into solenoid...0v What is causing that? Bad solenoid? Ground? Electrical isnt my strong suit. Is the safety switch wire from the safety switch, or from the key switch? Is the wire in good shape? Not broken or pinched, right? 1 Share this post Link to post Share on other sites
Pullstart 62,905 #5 Posted October 4, 2022 If you create a YT video and post it here, it might help us see what you see too 1 Share this post Link to post Share on other sites
DZG 32 #6 Posted October 4, 2022 11 minutes ago, Pullstart said: Is the safety switch wire from the safety switch, or from the key switch? Is the wire in good shape? Not broken or pinched, right? The wire ran to the safety switch. I was getting 12 volts to that, so i jumped the two wires togther first (basically bypassed switch) but couldnt get any juice to the solinoid wire. So thats when i fished the plug for the safety switch up top, ran a piece of wire from the hot lead going to the safety switch over straight to the solenoid wire. The safety switch wire is only hot when cranking, as far as the wires everythings taped up tight (like factory taping around the wires, not butchered), i didnt tear all that out. I figured by jumping the wire id get it to work. Heres the diagram... 1 Share this post Link to post Share on other sites
Pullstart 62,905 #7 Posted October 4, 2022 (edited) Maybe check continuity from the switch to the wire on the solenoid? It’ll verify the jumper and the wire are all in good shape. Edited October 4, 2022 by Pullstart 1 Share this post Link to post Share on other sites
DZG 32 #8 Posted October 4, 2022 4 minutes ago, Pullstart said: Maybe check continuity from the switch to the wire on the solenoid? It’ll verify the jumper and the wire are all in good shape. Ok...ill give that a shot. I just dont understand why i have power untill i plug it into solenoid lol 1 Share this post Link to post Share on other sites
Pullstart 62,905 #9 Posted October 4, 2022 In appliances, I’ve seen a sort of ghost voltage. It shows on the meter, but there are no amps due to a short or resistance. If you go from the battery straight to the solenoid, I assume it rolls over, right? 1 Share this post Link to post Share on other sites
DZG 32 #10 Posted October 4, 2022 26 minutes ago, Pullstart said: In appliances, I’ve seen a sort of ghost voltage. It shows on the meter, but there are no amps due to a short or resistance. If you go from the battery straight to the solenoid, I assume it rolls over, right? I didnt try that. Mainly cause the solenoid is hard to get to. Ive just been focused on getting power into that wire then going from there, but if i were to jump the solenoid i see no reason it wouldnt crank...both the cables are in good shape 1 Share this post Link to post Share on other sites
squonk 41,144 #11 Posted October 4, 2022 Ground the solenoid mounting and or clean the surface it sits on. . When you apply 12volts to the little terminal the solenoid should click as the coil pulls in. The body of the solenoid needs a ground to complete the coil circuit. If you don't hear and feel the click the coil isn't pulling in. If you have 12 volts and a good ground and still nothing solenoid coil is shot. 2 Share this post Link to post Share on other sites
DZG 32 #12 Posted October 4, 2022 23 minutes ago, squonk said: Ground the solenoid mounting and or clean the surface it sits on. . When you apply 12volts to the little terminal the solenoid should click as the coil pulls in. The body of the solenoid needs a ground to complete the coil circuit. If you don't hear and feel the click the coil isn't pulling in. If you have 12 volts and a good ground and still nothing solenoid coil is shot. I was wondering about that. Ill try that as well Share this post Link to post Share on other sites
953 nut 55,290 #13 Posted October 4, 2022 4 hours ago, DZG said: So i ran a wire right from the safety switch wire (only hot during cranking), to the solenoid wire. Had 12v at solenoid wire...plugged in solenoid,..nothing. Checked wire...0v. Unplug wire from solenoid...12v Plug into solenoid...0v If putting a load on a wire causes the voltage to disappear that is telling you that a connection between the test point and the battery. Do as @Pullstart suggested, run a small jumper wire directly from the battery to the small terminal on the solenoid and see if it closes and the starter turns over. Once we know that the solenoid is good we can trace voltage back to find the problem, probably a terminal that is corroded or needs to be tightened. 1 Share this post Link to post Share on other sites
ohiofarmer 3,276 #14 Posted October 5, 2022 I usually just unplug the kill wires on the coils themselves. That is an instant bypass to all the safety switches. Of course once the thing starts it will not shut off. I am not saying to leave the machine this way, but it is a useful way to determine what components [like the solenoid] are working or not. . I also like a test light . These things can be powered off the hot side of the battery and will light up when you hit a ground or vice versa. what that means is it will test both + and - wires. and will also become a jump wire even enough to crank the tractor. I did exactly that on my 314 recently and then added a temporary jumper [fused] with a momentary switch for the solenoid trigger. Share this post Link to post Share on other sites
DZG 32 #15 Posted October 5, 2022 All great info fellas. Im pretty busy rest of ths week but when i get a chance to run out and wrench on it some more ill let yall know what i find 1 Share this post Link to post Share on other sites
