Starter motor doesn't disengage.

[eglideic]

  A friend has a 1981 dresser and the starter motor doesn't stop turning the motor over when he stops pressing the starter button.
He motor isn't starting because of bad gas of dirty carb or who knows, but he doesn't want to pursue getting the bike started untill he solves the problem with the starter motor not disengaging.
We replaced the relay, solenoid, and cleaned the connections.
Any ideas? Would it be the starter motor? The bendix gear?

[FSG]

For the starter motor to keep spinning it must be still getting power from the solenoid.

Disconnect the starter from the solenoid and connect a 12 volt bulb between the starter terminal and ground, this will give you a visual indication as you work backwards towards the start button trouble shooting the problem.

Note there are 5 connectors between the start button and the start relay, thus there may be leakage between a 12volt supply line and the start relay operate line, not enough leakage to operate the relay but enough to hold it in once it's been operated by the start button.  Check/Clean the connectors, don't overlook the back of the relay base.

Do you have the wiring diagram?

[eglideic]

 Yes I have a Haynes Service manual.

[FSG]

I don't use them, is the wiring diagram OK.

[eglideic]

 Yes, the diagram is very good.
What do you mean when you say "Disconnect the starter from the solenoid and connect a 12 volt bulb between the starter terminal and ground"?
Do you mean disconnect the large gauge wire to the terminal stud on the side of the starter motor and connect the light there to the stud on the starter motor or the stud on the solenoid?

[FSG]

Diagrams   1980-1984_FL-FLH   &  1980-1983_FLHT  may be of some value also.
See the HTT Documents section,  http://harleytechtalk.com/htt/index.php/topic,16691.0.html

Disconnect the starter by lifting the large gauge wire on the side of the starter OR at the solenoid end, so it doesn't operate while you trouble shoot the problem.

If you have a voltmeter/multimeter then use it rather than a 12 volt bulb for checking the output of the starter solenoid.

[eglideic]

 So you're thinking the wire carrying voltage from the starter button to the relay is somehow still hot after you stop pushing the button, yet it doesn't have enough juice to start the turning over of the motor untill you first press the button?
That's hard to believe yet I'm no expert.

[FSG]

Yes it's possible, a relays hold in current and voltage is a lot lower than the current and voltage required to initially operate it. 

[eglideic]

OK. Then if it's doing that, I can just disconnect the black wire from the small terminal on the relay and use jump a wire from the battery plus + to that small terminal to engage the starter and it should disengage just as quick as I pull the jump wire away.
If the starter keeps turning, it's something else doing it.

[FSG]

yes, and that relay terminal should be #86

[Old Crow]

If you replaced the solonoid, also make sure the big cable to the battery is hooked to the long stud and not the short one.  That'll cause the solonoid to stay engaged, too.

[76shuvlinoff]

Yes it's a lot safer to substitute a volt meter or 12 volt light bulb in place of the starter while you troubleshoot. A bulb going on and off is a lot easier on the bike ...and your fingers... especially if you end up with the primary open and are probing around in there with the mechanical side of  things.

[easyricer]

On the early FLTs the starter relay controlled battery power to the solenoid and the starter motor. On FX and FLH it only controlled the signal from the start button to the solenoid. If the battery has a weak charge or the motor/primary is dragging it can actually "HOLD" the starter drive engaged on the FLH and FX models. When that happens, a lot of stuff can cook!
Starter problems, on our old bikes are very common. Most are due to battery cable, connections, and battery conditions. Start with the battery itself.
EASY

[billbuilds]

     Are you sure that you guys reinstalled the solenoid plunger spring when you replaced the solenoid? ?

[eglideic]

 Yes, it was assembled correctly and worked fine last fall.
I'm thinking the battery might be low like easyricer suggested.

[Harpo]

Need compression to get the starter to disengage.......in other words, if you've got the plugs out it won't stop spinnin.

[prodrag1320]

not true,starter should disengage with plugs in or not

[prodrag1320]

we`ve seen the soleniod weld the shaft to the shaft,or things (jackshaft & sloeniod) arnt straight and binding

[dablaze]

Start with the battery...most common cause of that issue. If you put on a new solenoid, another common fault is leaving out spacers, felt washer, improper order of components that can cause a weld like pro said, then you will see arcing on the brass washer on the plunger.


Craig

[eglideic]

 OK.  A lot of good tips here.
I'll help him check it out Thursday and see what we find out.

[Yukon]

My 66 FLH has done that twice in the last 12 years. It was a low battery charge both times.

[Lew]

A low battery can cause the starter contacts inside the solenoid to weld together, because the solenoid is week and allowing the contacts to bounce. The starter drive should work with the plugs in or out.  The solenoid receives power from the battery when engaged, so connecting the starter and battery cables backwards will cause the starter to run on.

Lew

[eglideic]

OK.  The bike has an electronic relay. I unplugged the relay and put a meter to the lead that goes to the starter button and push the button and there is power to that lead. Let go and no power.
I left the relay unplugged and jumped the long t=post to the small diameter post on the solenoid and the starter keeps running even after I remove the screwdriver It doesn;'t stop turning the motor over untill  disconnect the neg lead onthe battery.
  I reconnected the relay and removed the cable that goes to the starter from the short post on the solenoid and hooked the + of the test light to that post and the - to ground. Push the starter button and the test light comes on, release the button and the light goes out.
I turned my attention to why the bike wouldn't start and found two badly fouled plugs. I replaced the plugs and rehooked everything as it should be and fired the bike and by magic the started almost cured itself. The starter still sometimes hesitstes at stopping after you release the starter button. Like it's behaving good, but wants to be bad.
I'm thinking that it might be the tired old starter motor itself. I think I remember from somewhere that the solenoid uses the starter motor electrically somehow to operate in the manner that it does. Does this make sense to anybody?
But anyway it's working and starting pretty good for now, but I think it's just saving up to play hell on my friend sometime soon.

[76shuvlinoff]

I'm thinking that it might be the tired old starter motor itself. I think I remember from somewhere that the solenoid uses the starter motor electrically somehow to operate in the manner that it does. Does this make sense to anybody?

Once I had the connection come loose at the post on the starter from the solenoid. The starter would spin but the sol would not pull it in. That was a WTF moment till I found it.

I do not think you can blame a non disengaging starter on the starter. If all connections are tight and power is turning on and off at command with a known good fully charged battery then I would look at the mechanical.

[FSG]

We replaced the relay, solenoid, and cleaned the connections.

Was the solenoid new or another old one that was sitting on the shelf ?