Starter keeps running

[FD1571]

I've been chasing a gremlin in my 1988 70hp 3 cyl mercury s/n 0B 262212. My problem is my starter will intermittently continue to run after the motor starts. I have replaced the starting solenoid 3 times, ignition switch, the 8 pin connector w/harness and the starter. I just installed a Cole-Herse battery disconnect switch until I can find the problem. I have also installed a indicator light connected directly to the starter so I can monitor when it's getting power. While troubleshooting I noticed that on the small "negative " lug of the starting solenoid I get momentary voltage, as much as 7 volts when I am moving the ignition switch back from the start position to the run position, not sure if this is normal or not. I noticed this at several other ground locations. Also, it's an aluminum boat should I install a ground strap from the negative battery post to the boat frame ? I feel that I've checked everything any help would be greatly appreciated.

 

[gm280]

Well first things first. :welcome: to iboats FD1571. Glad you joined us...

I have to say this is an interesting dilemma for certain. Obviously the starter solenoid IS getting enough voltage to pull it in and spin the starter or the starter would never run. So seeing (or reading) that you already changed the starter solenoid (actually 3 times already) lets rule that out. And you also replaced the ignition switch as well. So those things are not the issue either. So it would seem like there is something in the wires causing this. Don't strap a ground to the hull. You want clean shiny metal grounds from the battery to the engine case though. And I would first clean that ground for starters. You also seem to understand electrical thing being how you added an indicator light at the starter to verify when it receives power. What sticks out to me is the fact that you state you can wiggle the ignition switch and it gets voltage at the starter solenoid. That seems interesting. IS the key switch touching anything behind it? Being an aluminum hull boat, is the ignition switch fitted to where it could be touching a metal portion of the boat and shorting across two terminals supplying voltage to the starter solenoid? Other then that, I would pull the wiring harness and check it for worn through wire insulations... Post back with more info...and some pictures if you can!

 

[FD1571]

Thanks for the welcome and comments.
The ignition switch doesn't wiggle. It's very solid. When I go from the start position on the switch back to the on or "run"position on the switch is when I see the momentary voltage spike. This is very perplexing to me and I was wondering if any of you experts out there had ever seen this before. If just seems very odd to have positive voltage on the negative ground lug of the starting solenoid. That's why I was leaning towards a ground issue.
The Mercury key switches don't have lugs on the back side, they are molded with only wires coming out, so a short there should not be taking place.
My plan is to take apart the controller again and continue to search there, I have ohmed out the 8 pin cable and everything seems OK, of course shorts in a cable that long are tough to find. My boat is quite the hybrid, I live in Maryland where all the lakes are electric only so most of the year my means of propulsion is a 60 volt Ray electric outboard with 10 6 volt deep cycle batteries. But 3-4 times a year I like to fish bigger water so I bought the 70 hp Mec. I've been to Canada twice Tenn. twice NC and am about to leave for Central FL. I'd love to get this mystery solved before I leave. Thanks again guys and I welcome your thoughts.

 

[Fed]

That momentary 7 Volts could be the magnetic field collapsing in the solenoid coil when you turn from start to run.

Think about putting the little indicator light across the starter solenoid coil to see if it loses power after you switch back to run.

Edit: extra thoughts... putting it into gear should break the circuit to the solenoid coil and I'd be wary about switching it off with a battery switch.

 

[GA_Boater]

One question with no answer so far - "should I install a ground strap from the negative battery post to the boat frame ?" No! In fact nothing should be grounded to the hull. Doing so makes the hull part of the electrical system and current flows through the hull causing the hull to be eaten up by the stray current.

Is the indicator light going off when the key is released? Try Fed's idea about moving the throttle lever when the start stays engaged. Move it slowly and the neutral switch should open before it shifts into gear and the starter should stop.

About the 7 volts thing. Make sure the starting battery connections are clean - Shiny bright. Also inside the motor where the ground and voltage wires are connected.

 

[FD1571]

Thanks guys for your comments, Fed I currently have the positive lead to the starter disconnected and can hear a very solid click coming from the solenoid in both positions i.e. The solenoid engages when the key is switched to start and disengages when the key is released into the run position. This is a no load test and thinking about it perhaps it should be a load test, but the solenoid seems solid. During a load test I can install the indicator light to the small leads on the solenoid .
So if I understand correctly, if I open the neutral safety circuit that should basically do the same thing as my battery disconnect. Gee, should have asked that one first. Could have saved 25 $$
I installed the battery switch as a safety. Every time this has happened I've been on the water, when I've turned the engine off with the key and the starter would be still running I would have to disconnect the battery to kill the starter. So I installed the switch to make this process easier and safer. I don't run any of my instrumentation through this starting battery.

GA Thanks for the help with grounding to the hull. Everything you said makes perfect sense.
When I get home today I'll break out the wire brush and go to town on all the connections. Unfortunately there is no rime or reason to this. Other than all these components are 27 years old. I opened up the controller again and it looks like 10 lbs. of spaghetti crammed into a 2 lb sack. I hate to keep throwing money at this but perhaps a new controller might not be a bad idea... All the wires seem to be intact but it wouldn't take much for a short to be happening in there, between all the crammed wires and all the moving parts. You guys have been terrific, thanks so much for helping me out.

 

[GA_Boater]

There never is a rhyme or reason when it comes to corroded connections. And they cause so many electrical problems that are seemingly unexplained.

I don't know if this is the source of you problem, FD. It's just worthwhile to try.

 

[Fed]

This circuit would be pretty typical of what you have.

I'd suggest if you've got no power between point (7) at the starter and the starter ground when it continues running then it's sticking in mechanically and being simply driven by the flywheel.
Easy to test.

 

[FD1571]

Fed, thanks for the diagram. That's exactly the set-up I have.
While going through and cleaning terminals, I did the test as you suggested and connected my indicator light to the coil on the solenoid. I have very solid contact at this point as well, good solid light every time I switch the key to the start position and no light in the run position. I feel that the solenoid is not the problem but something is intermittently engaging it causing the starter to run. But when this happens it holds the solenoid engaged and won't release until I disconnect the battery.
I did notice something strange though, with my volt meter across the 2 small terminals on the solenoid if I push the key in to activate the "choke" I get no voltage but when I release the key I see the momentary + - 7 volts. Only when I release the key. Same as with the solenoid from earlier , but this time there is no coil collapsing to cause this. With the starter issue being so intermittent it's very hard to diagnose. But this strange voltage I keep seeing happens every time, it may be perfectly normal I'm not sure. (no electrical engineer here ). Again this is without the starter hooked up, but everything up to that point working.
Again thanks so much for your help. As far as the starter goes I may have to wait until it happens again to gather some additional clues.

 

[Fed]

this time there is no coil collapsing to cause this

When you energize a coil a magnetic field builds up around it, when you disconnect the power the field collapses and induces a reverse Voltage in the coil. Don't worry about it.

I find it pretty hard to believe it's holding in because there's power on the solenoid coil.
Firstly the neutral switch should stop it as well as the ignition switch which you have replaced.

I have replaced the starting solenoid 3 times

Genuine Mercury parts?

 

[FD1571]

Thanks again Fed, yes genuine Merc parts. When I replaced the ignition switch last year I replaced the neutral safety switch at the same time. (Figured while I was in there might as well)
I remember last year in TN when this first happened I was fishing back in a cove and my buddies were out on the main lake, they call my cell and wanted me to meet them. So I fired up the Merc and motored about 5-10 minutes to their location. When I got there I shut down my Merc and that's when i noticed the starter was still running, the bending was not engaged but the starter was running. When I opened the cowling you could tell the starter had been running the whole time. It was very hot. All that being said, with your scenario about the neutral safety switch stopping the power to the solenoid, that didn't happen, because I was at 3/4 throttle in forward gear for the 5-10 minute ride. So does the neutral safety switch open the circuit on the yellow/red wire going to the positive side of the solenoid when the throttle is engaged ? I think that's what your saying, if so I can easily test that. Thanks for helping me sort this out.

 

[Fed]

So does the neutral safety switch open the circuit on the yellow/red wire going to the positive side of the solenoid when the throttle is engaged ?

Correct.

As there is only that single yellow/red wire going to the solenoid coil it seems unlikely the solenoid coil is getting power when it shouldn't.

A short circuit to another hot wire?
Something wired incorrectly?
The lug on terminal #1 touching the lug on terminal #3 ? (see diagram)

It all sounds like a stretch.

 

[FD1571]

Fed, before your help I was leaning towards some sort of back feed through the solenoid that was energizing it and keeping the starter running, mainly because I was seeing the voltage spikes.. But now that I know the neutral safety switch should be opening the circuit on the yellow/red wire, I feel I have some place tangible to start.
So tomorrow I need to place my volt meter on the small lugs on the solenoid then while holding the ignition switch in the "start" position move the throttle enough to open the circuit. The voltage should drop to 0. If not then I have a problem in that circuit, either the neutral safety switch or the wiring in that circuit. One other question; with the ignition switch in the "run" position does the motor get any voltage through the ignition switch through any other circuits. I'm looking for a place to test the neutral safety switch with the ignition switch in the"run" position not just the "start" position. Again thanks so much for your help

 

[Fed]

So tomorrow I need to place my volt meter on the small lugs on the solenoid then while holding the ignition switch in the "start" position move the throttle enough to open the circuit. The voltage should drop to 0. If not then I have a problem in that circuit, either the neutral safety switch or the wiring in that circuit.

Or you could simply put it in gear and try to start it.
The neutral switch is there to stop people accidentally starting in gear.

As hard as it is I think you need to prove one way or another if the yellow/red wire on the starter solenoid is getting power to it (or not) when the problem occurs.
Nothing worse than an intermittent fault, how often does it happen?

 

[FD1571]

Hi Fed, I performed the neutral safety switch and it worked just fine as I expected. With the ignition switch in the start position, I moved the shifter in both forward and reverse and the circuit opened every time. At the expense of my engine looking like a Christmas tree I can install an amber light to the positive and negative terminals on the solenoid. The light on the starter circuit is red.
It doesn't happen very often, because of the way I use my gas engine it's really hard to say, most of the year my boat is 100% electric. I leave for Fla at the end of the week. I will take it to the lake 4-5 times while I'm there, probably starting it 20-30 times so we'll see how it does. I feel more comfortable now that I've installed the battery disconnect switch as a last resort to keep from burning up the starter. If it happens again the first thing I will do is turn off the key to stop the engine then put the shifter in gear to see if the neutral switch will kill the power to the solenoid/starter. The intermittent nature of this is definitely the biggest challenge I have. Thanks again I keep posting from Fla.

 

[Fed]

The extra light sounds like a good plan at least you will know exactly what's going on as soon as it does its thing.

 

[Mift]

I have the same problem and symptoms with 1988 crusader electric solenoid randomly engaging. What was your final solution? I read the entire thread and learned a ton. I chewed up the new starter. I have my neutral safety switch hard wired and will fix asap so I can shift gear to force power off to starter. hopefully the hard wired neutral safety switch is not causing my problem. The engine started and ran fine for 3 minutes and then solenoid engaged on its own and ground away until worthless.

 

[Mift]

Mr Cadet. I followed your entire thread and I have similar issue. What solved your issue? I chewed up 2 starters and will remove hard wired neutral safety switch and replace ignition switch too. hopefully hard wired neutral safety switch cannot randomly put power to solenoid after engine is running for 3 minutes.

 

[GA_Boater]

Mr Cadet. I followed your entire thread and I have similar issue. What solved your issue? I chewed up 2 starters and will remove hard wired neutral safety switch and replace ignition switch too. hopefully hard wired neutral safety switch cannot randomly put power to solenoid after engine is running for 3 minutes.

Mr. Cadet was active in the forum for only 6 days back in 2015. I don't think you will be getting any answers from him.

This is why we ask that threads which are inactive for 90 or more days be left dormant. Please start a new thread of your own so you have chance at getting answers from current, active members.

Closed.