Start / stop switch malfunction, Perkins 6.354

[BrianSmith]

We bought the 1974 Gulfstar MkII Sundeck Trawler (43') in May. (After lots of great input from y'all, thank you very much!) One of the pre-purchase survey items was that none of the start / stop switches (actually, they're pushbuttons) at the upper helm station work. Yesterday, I finally got around to some troubleshooting.

Bottom line: one of each now works, and one of each doesn't. The switches are all the same, a simple pushbutton, that when pushed, closes the circuit. So to troubleshoot, I simply removed both wires from the back of the switch and touched them together. (As a result of this, I replaced two faulty switches, which solved two of my four problems.)

There is 12V on the positive wire, tested with a volt meter. Also, I get a little sparking when I touch them together. So I know there is power getting to the switches.

The stop switches (buttons) on the lower helm station both work. The start switches on the lower helm are activated by turning the ignition keys, and they both work.

I believe the stop switch works by activating a fuel cutoff solenoid at the engine, but since the lower helm stop buttons both work, I'm inclined to NOT suspect the solenoid. Seems like the most likely cause, therefore, is a problem with the wire "leaving" the switch, somewhere on its way to the solenoid. Agree? Or am I missing something? I don't want to go on a wild goose chase for a broken wire.

I believe the start switch works the same way, but by activating the starter solenoid. Again, since the lower start switch DOES work, I suspect a wiring problem, not a solenoid problem. Agreed?

Thanks so much for any help - even if it's just confirming my diagnosis.

 

[psneeld]

with the key switches on or engines running...are you getting 12V to one side of the "kill"/"stop" switches up there?

Not always... but check the lower ones first to see that it's a power to the solenoid kill rather than the power off kill....and there is 12V to one side.

If so...there should be 12V to one side of the uppers too. you may have to find the origin of 12V to those upper switches and make sure there is a circuit when pressed all the way to the solenoid or the (dead) side of the lower switch which would finish the circuit to the solenoid.

 

[BrianSmith]

with the key switches on or engines running...are you getting 12V to one side of the "kill"/"stop" switches up there?

Not always... but check the lower ones first to see that it's a power to the solenoid kill rather than the power off kill....and there is 12V to one side.

If so...there should be 12V to one side of the uppers too. you may have to find the origin of 12V to those upper switches and make sure there is a circuit when pressed all the way to the solenoid or the (dead) side of the lower switch which would finish the circuit to the solenoid.

Hadn't thought of that (obviously). OK, I'll check the lower switches, too, for what you suggest. Thanks! (But to answer your first question, yes, there is power to one side of the stop switches when the engines are running. That was one of the first things tested.)

 

[FlyWright]

One solenoid on my Perkins failed with LOW voltage to the solenoid. A faulty splice was the culprit and replacing the wire solved the issue. I had a similar problem on one start circuit as well. I have found splices in lines where you'd never expect to see them. Replacing the wires is standard maintenance practice now on my 32 year old boat.

 

[BrianSmith]

One solenoid on my Perkins failed with LOW voltage to the solenoid. A faulty splice was the culprit and replacing the wire solved the issue. I had a similar problem on one start circuit as well. I have found splices in lines where you'd never expect to see them. Replacing the wires is standard maintenance practice now on my 32 year old boat.

OK, if I don't find any breaks, I'll verify the voltage all the way to the solenoids. Thanks!

 

[Billylll]

I think you will find the upper helm is missing +12 VDC required to turn off the fuel to the engines. This could be a common +12 VDC for both engines. Power is required to activate the fuel shut off solenoids on Gulfstar 36 & 43 Mark II's.
Bill

 

[Cat Daddy]

Mine is a Yanmar system and the lower helm key has to be on for the upper to work. May not be the case for yours, but an easy thing to check.

Good luck,

Rafe

 

[psneeld]

Mine is a Yanmar system and the lower helm key has to be on for the upper to work. May not be the case for yours, but an easy thing to check.

Good luck,

Rafe

It's a good point as most kill switches are in the start/instrument panel circuit....

many are wired so that the "start" keys must be on...not all and not sure it should be that way anyhow.

 

[High Wire]

Put your voltmeter across the stop solenoid terminals and push the lower stop button. Read the voltage. go up top and push the stop and read the voltage. Should be close to the same. If more than a volt lower, bypass the wire to the sol with a length of #16 wire and repeat. It should read higher now and the sol should work. If not, the problem is on the +12v side of the button. Jump from the +12v side of the same engine Start button.

 

[CaptTom]

I have the same engines, and the same issues.

Someone re-wired the lower start switches to an off-on-start key switch, so the lower start pushbuttons do nothing. The lower stop buttons work fine.

At the upper helm, nothing works unless the key switch is on at the lower helm anyway. I think one start pushbutton works, along with one stop. Since stopping from the upper helm causes the low oil pressure buzzers to alarm until you turn off the key anyway, this is a low priority.

I hope you'll share what you find, maybe it'll save me some time when I re-do my upper helm.

 

[BrianSmith]

BillyIII and Highwire:

I think your two posts are what I'll need to solve the problem. After just removing all of the switches for testing and reinstalling them all, I now have only one remaining problem switch - one of the stop switches. And it has worked intermittently since the removal and replacement. So my next step will be to do the tests you two suggested, and make sure all the connections are really clean.

Thanks, all, for all your input! Capt Tom, I'll post the final fix, to make your job a little easier, hopefully.