Help with riding mower- not starting

[Skytard]

Okay, so I was asked to work on a riding lawn mower. Originally I was told it just needed a new battery because it wouldn't start and the battery wouldn't hold a charge. I replaced the battery and still no start. I used a multimeter to trace the power from the battery to the ignition switch to the safety switch and then to the condenser solenoid. On the solenoid there are 3 wires. 1 wire from the battery, 1 line from the ignition switch, and 1 line from the solenoid to the starter. I got 12.60V to power terminal, 12.60V to the terminal from the ignition switch when I turn the key. I don't get anything coming out of the terminal that goes to the starter. I figured bad solenoid so I replaced it but same thing. No power coming out of the solenoid but power going in. I can hot wire it by bridging both the power in terminal and the power out terminal and it starts right up so I know everything after the solenoid works. I'm stumped why a brand new solenoid won't have any power coming out of it. I don't think it's the ground because it grounds to the body and I cleaned that up before installing the new solenoid. When it still didn't work I wired up a ground to see if it was the ground and it still wouldn't work.

Does anyone have any idea what my problem is? I don't know what could be wrong with a brand new solenoid. I've hit a dead end.

 

[KennyV]

WELCOME to LMF...
Do you ever hear the Starter Solenoid Click ?
Jump from the Battery Positive terminal to the small terminal... what happens?

It is possible that you did get a bad starter solenoid, but that is very unlikely... :smile:KennyV

 

[OzRanga]

How many 'small' posts/terminals are on the solenoid? One or two?

(This is apart from your two large posts that go from battery to starter motor.....)

 

[Skytard]

How many 'small' posts/terminals are on the solenoid? One or two?

(This is apart from your two large posts that go from battery to starter motor.....)

The old solenoid had 1 small post. The new solenoid had 2 small posts but one of them said to only use it if you needed a second smaller post. Apparently it's a ground so I wasn't worried that it wasn't the exact same solenoid. I was told it was a pretty universal part and the new one looked the exact same except that extra small post.

Thanks for your reply:thumbsup:

 

[Skytard]

WELCOME to LMF...
Do you ever hear the Starter Solenoid Click ?
Jump from the Battery Positive terminal to the small terminal... what happens?

It is possible that you did get a bad starter solenoid, but that is very unlikely... :smile:KennyV

No, there is no click. Jumping from the positive battery terminal to the small terminal on the solenoid doesn't do anything. I already knew that though because I was getting over 12V at that smaller terminal when I tested with my multimeter.



Can anyone explain how a solenoid like this works? Power goes in and then something happens and then power goes out. Why cant the ignition switch be wired in between the battery and the starter? It sounds logical to me. I have a lot of experience in automotive but I've never had to dig into an electrical problem like this before. In my experience, there's always either an answer or more to consider. It seems to me that I don't have anything else to consider here if I have tested everything and I know I lose my power inside the solenoid. If you asked me how sure I was that the solenoid just needed to be replaced earlier I would have said 100% and I never trust myself that much, so you can maybe understand my frustration when that didn't fix the problem.

Sorry for the lengthy post, just frustrated.

 

[KennyV]

You can Not run all the current needed for the starter through the key switch... that's why the solenoid is there... it is simply a high current switch that is electrically activated by the key switch...
IF your new solenoid has a ground terminal for the solenoid Coil, It will Not work until you give the coil a permanent ground. Most solenoids are grounded through the mount to the frame.

Measure continuity between the small terminal, and the frame or battery negative post.... It should be very low ohms resistance, nearly a short.... If you have no continuity, check between the two small terminals..
:smile:KennyV

 

[OzRanga]

As KennyV rightly says, the second small terminal must be grounded for the solenoid to work...that should fix it