A friend has a 1981 FLH and when he pushes the starter button the starter motor stays on and keeps turning the motor over untill we disconnect the battery. Also if you jump the two posts at the solenoid it does the same thing, so it's not the starter button. The battery is almost new and shows about 12.7 volts, so we don't think it's bad. We checked the wiring and it's all correct. We tried two different NEW solenoids in it, a new solenoid coil spring, a new bendix gear, and tried a new relay with no luck.
Could it be a bad or weak starter motor? Somewhere I think I heard that the solenoid uses the starter motor as a ground mass or something like that.
Any ides?

 

12.7 ain't a great reading on a rested battery.
Get the battery on a charger over night.
Get the charge up to high 13's or low 14's.
Since you have tried a bunch of new electrical parts, maybe the problem is a binding in the starter gear. Have you worked on the starter drive gearing/shaft just prior to this problem?
Have you removed/replaced the inner or outer primary cases?
The cheapo aftermarket cases have poor quality control and do not align the gearing properly at times.
It could be the starter drive gear is binding when engaged with the ring gear on the clutch shell.

 

Mine did the same thing to me a while back. Ended up being that the plunger in the starter solenoid was gunked up. I took the solenoid off and cleaned off the plunger parts and re-lubed them. Seemed to work just fine after that.

 

Yeah but we put in TWO different new solenoids (one el cheapo, and one US made ACCEL) with no luck. But thanks for your reply.

 

Did you just replace the solenoid or the solenoid and plunger assembly? Just asking cause at first i did just the solenoid and then it did what you are describing until i took the solenoid off and cleaned off the plunger and assembly and re-lubricated it. That's all I got for you.. hahah.. wish I could help more.

 

The New solenoids came with New plungers. I've never seen a new solenoid sold without the plunger.

 

Humm a lead acid 12 volt battery fully charged is 12.7 +-
They might charge at 14 volts but no way will it read that much not on charge.

 

once upon a time ACCEL was USA made they have outsourced to china for more bang

look at the box again

 

Well instead of always using the Battery Tender as I do nowadays, I got out the old 2 amp - 6 amp charger and put it on two amp for several hours and now the battery is reading 13.5 volts (with the charger disconnected).
I'll leave it charge for a few more hours, disconnect it, take a reading and leave it disconnected and see if it still holds that charge overnight.

 

Well you can over charge a battery and get a temporary reading higher than 2.14 per cell but that is not a real world working voltage. You never check the voltage right after it is charged you need to let it sit.
2.14 x 6 = 12.84 and 100 percent charge state is 12.7-12.75 on a new battery.

http://www.mmbalmainauto.com.au/PDF/..._batteries.pdf

A battery that reads 12.7 volts is not going to cause this problem.
.