Strange Starting solenoid issue

[dstixs5]

This is my first post but have been a long time lurker.

I've got a 1999 Mercruiser 350 MPI - Ski/Inboard motor. I've got a strange issue with the solenoid/starting. The starter will not engage/turn over. I checked for 12v on the yellow/red wire at the starter, and regardless of key position, 12v is there. The starter solenoid will overheat within seconds(probably needs replacing again now). 12v on this wire 100% of the time. I did replace the starter before i found this issue(bench test failed). I then backed up to the slave solenoid. The solenoid will click once the key is turned. I found that both of the large posts on the solenoid are 12v regardless of key position. Going by various troubleshooting guides I've found out there, this is not right. The large yellow/red should only activate when the slave solenoid is engaged by the key. I'm not sure where there problem lies or where to even start now. Any suggestions would be much appreciated as I couldn't find any other posts out there with similar symptoms.

To be clear, I have replaced the starter and slave solenoid on top of the motor. There is 12v at both the large posts on the slave solenoid atop the motor.

 

[Grub54891]

Re: Strange Starting solenoid issue

Has it ran before,or is it a new to you boat? Have you added/changed the wiring recently? Is the battery hooked up corectly? Could be many things,but I'd start with the battery,then check the ignition switch,they do go bad at times,that would cause your power issue.
Keep us posted,and I'm sure others will cheme in.

 

[NHGuy]

Re: Strange Starting solenoid issue

Here's the diagnostic guide I use. http://forums.iboats.com/mercruiser...ting-your-engines-starting-system-167035.html
Confirm your wire connections at both solenoids and at the key switch. Also check that the switch is sending power where it should, when it should. How about terminal ends, clean and snug? Grounds same?
It sounds as if the slave or the key switch is your issue.

 

[dstixs5]

Re: Strange Starting solenoid issue

I've had the boat for 3 years. At the end of last season, it started the issue. No wiring changes. When it was really hot over the summer, I would sometimes get the click/no turn over last year. I did clean all terminals on battery and solenoid.

When the key switch is in the on position, the gauges light up and I hear the fuel pump load, then in the start position, the solenoid will click as It should. Are you saying there still could be issues with the switch?

 

[dstixs5]

Re: Strange Starting solenoid issue

I have already referenced this guide. I have 12v all the time on terminal B regardless of key position - on/off/start.

As info, I only get 12v on terminal C when in the start position.

 

[achris]

Re: Strange Starting solenoid issue

Have you verified that you are getting 12volts onto the START terminal on the starter? That would be the small yell/red wire going to the starter itself (well, the solenoid on top of the starter). If you are not getting that, check the neutral safety switch....

Chris...

 

[dstixs5]

Re: Strange Starting solenoid issue

That is the problem(I think). I'm get 12v there 100% of the time. I know this is not right.

I believe the neutral switch ok, only because the solenoid will not engage/click at all while in gear

 

[achris]

Re: Strange Starting solenoid issue

No, you should have constant 12 volts ONLY on the main big red cable that runs directly from the battery (maybe via the battery switch). The small yell/red wire is the wire that energises the solenoid and pulls it in so the motor can turn, which cranks the engine.... That wire should ONLY have 12 volts on it when you turn the key to START....

Chris....

 

[JustJason]

Re: Strange Starting solenoid issue

You either have a stuck keyswitch or a stuck slave solenoid.

Disconnect the yellow/red from the input side of the slave solenoid and retest. If your voltage on the yellow/red at the starter solenoid goes away, it's a bad keyswitch. (or short in the harness). If you still have voltage on the yellow/red at the starter solenoids, it's a bad slave solenoid.

 

[dstixs5]

Re: Strange Starting solenoid issue

JustJason,

Are you suggesting I take the small yellow/red wire from the side of the slave or the bigger yellow/red from the larger post on the slave?

 

[JustJason]

Re: Strange Starting solenoid issue

Take the yellow/red off of the smaller post

 

[dubs283]

Re: Strange Starting solenoid issue

the way you describe it, with 12 volts at terminal "B" at all times, the starter motor should be engaged and the engine turning over constantly

no doubt the slave solenoid is faulty, there should only be 12 volts at terminal "B" when terminal "C" is energized by turning the key switch to "start"

but if the starter isn't cranking, you have a wiring issue, battery issue, starter issue, or all three along with a faulty slave solenoid

 

[Bt Doctur]

Re: Strange Starting solenoid issue

A the red/purple will have 12v constant
B the yellow/red large wire goes to the starter solenoid lug closest to the block
C the small yellow/red wire has 12v when the key is turned to start position only
D solenoid ground.
The way you describe it, the starter should turn constantly. so that might mean your not using the meter correctly or you have a poor ground connection on the negative battery cable end at the motor. You able to read voltage but no current can flow to activate the solenoids or starter.
A quick test is to jump the starter solenoid and slave.
1 short the 2 large lugs of the slave, starter should operate Y N
2 short the small lug closest to the block with the battery cable lug of the starter ,starter spins Y N
No means a bad battery cable connection

 

[dstixs5]

Re: Strange Starting solenoid issue

Thanks for all the replies. Bt Doctur, thats what bothers me about the whole thing. The starter will not engage - the starter solenoid gets extremely hot if i leave the yellow/red wire or battery connected. Its a brand new starter and slave solenoid. Didnt bench test. I plan get back to it this evening and try out some of these suggestions and test the new parts properly. I bought OEM in an attempt to not have these types of concerns.

I know how to use a meter. I'm new to boats and their electrical systems. Had sea-doos all my life but have never dug into a boat motor.

 

[dstixs5]

Re: Strange Starting solenoid issue

I will thoroughly check all the grounds tonight. I did ground my meter on the starter bolts to verify the voltages on the solenoid and at the starter. I'm not sure it that would eliminate the need to further check the grounding.

 

[Bt Doctur]

Re: Strange Starting solenoid issue

The starter will not engage - the starter solenoid gets extremely hot if i leave the yellow/red wire or battery connected

Do you mean the slave or the solenoid mounted to the starter .if starter mounted one, then solenoid is shorted internally . The only way would be to backfeed from the starters solenoid thru the yellow/red wire to read voltage at the slave.

 

[Bt Doctur]

Re: Strange Starting solenoid issue

That's the biggest thing with voltage and current. ever have a condition where the car motor would not crank, just a clunk. but when you turn the headlights on, there bright until you hit the key. then they go off or very dim. Current is what makes things work.
Given the corrosion factor in boats I use 2 things. A good multi meter and a headlight with pigtails. meter tells you that voltage is there, headlight tells you enough current is there.

Removing the yellow/red wire or battery cable should be producing a spark

 

[dstixs5]

Re: Strange Starting solenoid issue

The solenoid mounted to the starter

 

[Bt Doctur]

Re: Strange Starting solenoid issue

with the yellow/red wire off the starter solenoid ,do test 2. starter must operate and spin motor. If N, starter motor or solenoid is bad

 

[dstixs5]

Re: Strange Starting solenoid issue

Resolved. Thank you everyone who took the time out of their day to share their thoughts and opinions. It ultimately helped me pin the issue.

Issue - the freaking solenoid on my "brand new oem" starter was mounted and installed reverse. This was causing the yellow/red trigger wire to be energized incorrectly.

The boat is now starting and running correctly.