Briggs 18hp Opposed Twin - Solenoid Issues

[dougand3]

Briggs 422707 18hp Opposed Twin in Craftsman lawn tractor ~ 1989 model. Got a new 3 lead solenoid cuz I was having hard crank issues and solenoid looked old and worn.. Briggs OEM 4441931 solenoid. Key switch to start gives a nice solenoid thunk but no starter action. Got 12.7v on battery side big terminal (constant). Got 8.9v on small terminal (key to start). 0 voltage on engine side big terminal (key to start). The key switch is new, too - old one was so loose inside that I replaced it.
Is 8.9v too low even with nice thunk? Bad solenoid from the factory? Thanks, Doug

 

[SeniorCitizen]

Briggs 422707 18hp Opposed Twin in Craftsman lawn tractor ~ 1989 model. Got a new 3 lead solenoid cuz I was having hard crank issues and solenoid looked old and worn.. Briggs OEM 4441931 solenoid. Key switch to start gives a nice solenoid thunk but no starter action. Got 12.7v on battery side big terminal (constant). Got 8.9v on small terminal (key to start). 0 voltage on engine side big terminal (key to start). The key switch is new, too - old one was so loose inside that I replaced it.
Is 8.9v too low even with nice thunk? Bad solenoid from the factory? Thanks, Doug

I would have the battery load tested OR you can do a kind of a shot in the dark load test by connecting directly from the battery to the starter with jumper cables.

 

[Rivets]

I would check to see if you have an excellent ground between the solenoid and the frame or chassis. I think you are losing power through the new solenoid due to a bad ground.

 

[dougand3]

I WAS thinking battery, too, SandburRanch. It is a car battery - 525 CCA (the bay is humongous in this old Craftsman). It's fully charged. Took battery to Auto shop and it tested good. I will try straight jumping when I get back to it Fri.

 

[dougand3]

Good point, Rivets. I'll pull solenoid and sand frame under it real well.

 

[ILENGINE]

If that doesn't fix it, then you need to clean all of the electric terminals between the key switch and the solenoid.

 

[dougand3]

Thanks, ILengine. I jumped starter to battery and it spun up. Cleaned frame and solenoid chassis to get get good ground = no joy. I now get better voltage on small solenoid terminal with key to start = 9.7v. Should this be 12v? From what I see - Key switch to seat safety to brake safety to PTO safety to small solenoid spade...does that seem right? Thanks, Doug

 

[dougand3]

I straight wired S terminal from ignition switch to small terminal solenoid = no joy. Still good thunk but no power on starter side of solenoid. Neighbor had a spare 3 lead solenoid...it spins like a champ now. So, brand new Briggs OEM solenoid is defective..ARGGHHHH!!!
Lesson here - the magnets may thunk but power may not get to other side.
Thanks for the input, guys.

 

[EngineMan]

Thanks, ILengine. I jumped starter to battery and it spun up. Cleaned frame and solenoid chassis to get get good ground = no joy. I now get better voltage on small solenoid terminal with key to start = 9.7v. Should this be 12v? From what I see - Key switch to seat safety to brake safety to PTO safety to small solenoid spade...does that seem right? Thanks, Doug

I still believe you have a problem with the key switch or safety switch(s) somewhere, having a bad solenoid will not give you 9.7volts on the small lead, that is feed to, and not from, you should have battery volts at that lead when you turn the key to start, so remember this the problem may come back. You may well have had a problem with the new/replacement solenoid, and manage to work it on the 9.7volts but you are still down on the volts.

 

[dougand3]

Yes, EngineMan - understand what you're saying. When I straight wired Key switch S to small solenoid terminal, I got 12.1 volts. So, I'm losing ~2.5 volts somewhere in the safety switch path. I need to chase that down.