70hp No power to starter with key Intermittant.

[Grant Brown]

70 Merc 3 Cyl serial # 0A739874 Starts and runs great. Occasionally it will not turn over with the key switch. Solenoid clicks but won't turn over. Usually if I try it a second time it will work. Today it did it again only this time it wouldn't work anymore at all. I trailered it home to test it and once home it worked fine again and then did it once more. Now it seems totally fine, starts up no problem and runs great at idle.

The kill switch is in the run position.

Could it be the solenoid?

Tomorrow we are supposed to go out again with kids and friends about 15 miles up a remote inlet but I'm not going anywhere if the thing won't start reliably...

Grant

 

[jebeebe]

Re: 70hp No power to starter with key Intermittant.

I would bet on either bad cables,battery,or selenoid. The selenoid is just a pair of contacts with a brass washer that slides down a shaft and contacts both contacts. I took one apart once and one contact was covered with green powder and wasn't makeing good contact. bought a new selenoid ($20) and it fixed it......Check all cables and cable ends and make sure the nuts are tight..................Jerry

 

[Grant Brown]

Re: 70hp No start - now it's really messed up

Re: 70hp No start - now it's really messed up

Went out again today just local and close in. Like I expected the thing finally quit. I'm pretty sure it was the solenoid. Anyway while I was back at the dock tied up trying to see if I could get it to start, some bonehead comes flying up and lets off the gas at the last minute and throws up a nice wash through the launch area. I had the power cable in my hand and tapped it against some sort of ground on the engine. Almost sure on one of the studs on either a coil or the other thingy beside the coils. It sparked pretty good and now when I try to start, it's got a warning horn in addition to the usual one when the key is in the on position. The new one does not stop and it sounds quieter but a higher pitch.

I wonder what I fried.

Is there a way to hot wire the starter and bypass the key switch?

 

[jebeebe]

Re: 70hp No power to starter with key Intermittant.

With the key on, if you ground across the two big studs on the selenoid it should start. That will tell you if the selenoid is bad because that is what the contacts do. The little studs are.........one a ground,........and the other a 12v to pull in the contacts connecting the two big studs............Jerry

 

[Texasmark]

Re: 70hp No power to starter with key Intermittant.

When jebee said ground across the two big studs he really didn't mean hook them to ground. What he wanted you to do is "short" across them....make the connection to the starter on the outside of the solenoid rather than internally. Just do it long enough to see that it works. Pliers may get warm and will spark when you touch the terminals. Touching the nuts will keep you from arc welding the threads which will make it difficult to remove the nuts later if necessary.

Have used a pair of common pliers many times.

Causes of your problem:

1. Sulfated battery/under charged battery....have it load tested at Autozone or equiv at 200 amps

2. Corroded terminals on the interconnect cables between the battery and engine or starter. Both red and black wires, both ends, under the attaching hardware (remove it to clean then reinstall) they need to be clean and shiny and the attaching hardware needs to be good and tight...on the engine and battery, 12v wire and ground. Also the wiring between the solenoid and the starter.

3. Solenoid contacts pitted from wear causing reduced surface area that will not allow adequate current to flow to spin the starter, or have a high resistance surface from arcing when the starter is released.

Mark

 

[jebeebe]

Re: 70hp No power to starter with key Intermittant.

When jebee said ground across the two big studs he really didn't mean hook them to ground. What he wanted you to do is "short" across them....make the connection to the starter on the outside of the solenoid rather than internally. Just do it long enough to see that it works. Pliers may get warm and will spark when you touch the terminals. Touching the nuts will keep you from arc welding the threads which will make it difficult to remove the nuts later if necessary.

Have used a pair of common pliers many times.

Causes of your problem:

1. Sulfated battery/under charged battery....have it load tested at Autozone or equiv at 200 amps

2. Corroded terminals on the interconnect cables between the battery and engine or starter. Both red and black wires, both ends, under the attaching hardware (remove it to clean then reinstall) they need to be clean and shiny and the attaching hardware needs to be good and tight...on the engine and battery, 12v wire and ground. Also the wiring between the solenoid and the starter.

3. Solenoid contacts pitted from wear causing reduced surface area that will not allow adequate current to flow to spin the starter, or have a high resistance surface from arcing when the starter is released.

Mark

Mark,
you are correct. I should have made that more clear. Some times we assume people know what we are talking about when we say it wrong. Thanks
......................jerry

 

[Grant Brown]

Re: 70hp No power to starter with key Intermittant.

Mark,
you are correct. I should have made that more clear. Some times we assume people know what we are talking about when we say it wrong. Thanks
......................jerry

Never assume anything when you're talking to me!
I started it today with the key in the on position and jumped the terminals like posted above.
What now?

Grant

 

[jebeebe]

Re: 70hp No power to starter with key Intermittant.

I would say replace the selenoid. If you can jump across them and start then the selenoid isn't makeing contact inside. I think the selenoid is about $20 as I remember. Good luck...................Jerry

 

[Texasmark]

Re: 70hp No power to starter with key Intermittant.

Agree. If you can hear it click when you turn the key to start but no current to the starter the contacts are crudded up and it's time for a newun. You just proved it.

Glad you found your problem.

Hear you jebee. I do it all the time also sometimes say something totally different than what my brain is telling my mouth to say. The older I get the worse it gets. Grin.

Mark

 

[Grant Brown]

Re: 70hp No power to starter - loose solenoid studs

Re: 70hp No power to starter - loose solenoid studs

I started going through all the wiring on the motor cleaning each connection, coating with dielectric grease and making sure everything is tight.
I noticed that the studs where the power wires attach to the solenoids are turning on some of the 3 solenoids. It seems to me they shouldn't turn at all. Now the trim/tilt doesn't work any more. I have been having troubles with it lately. I wonder if a turning stud has broken the connection.
I also notice that 2 of the 4 - 3/8" bolts holding the solenoids on the motor are twisted off like they've been replaced before.

Is there a trick to removing the 3/8 bolts without breaking another one?

Should the solenoid power wire studs turn?

Thanks,
Grant

 

[Texasmark]

Re: 70hp No power to starter with key Intermittant.

No electrical stud should turn for the reason you surmised (brakes the internally attached wire) and a loose stud makes it difficult if not impossible to tighten the nut on the terminal adequately to hold the terminal lug you are attaching.

Mark

 

[Grant Brown]

Re: 70hp No power to starter with key Intermittant.

Replaced all three solenoids today - what a difference. The motor turns over nice and fast and the trim/tilt are faster and easier then ever before. I was thinking that I needed a new tilt/trim motor (at $300 I'm sure glad it was the solenoid).
Thanks to all who helped.

Grant in Vancouver