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Starter / Ignition issue

Posted: Thu Jun 04, 2009 10:41 pm
by LandVF36
1973 F36 dual helms.
I can start and run both engine from the lower station. Works perfectly.

From the fly bridge, I can start and stop the starboard engine. If I run for 1-2 hours and come back to the dock, shut off with the key. 1-10 times the starter will engage and not shut off. Cycling the keys 2-3 times from either the upper or lower helm will shut it off. Its a pain. I'm thinking that this is just an ignition switch issue and plan to replace this weekend.

From the fly bridge, I can turn the key on the port engine, it turns and starts but as soon as I let go of the key, it returns to the IGN possition and the engine stops. Its been this way since I bought the boat 3 years ago. If I start from the lower helm, I can restart from the bridge if it stalls, but I can not stop this engine from bridge.

It didn't bug me at first but as I've put other issues to rest, it occured to me that this is a safety issue that needs attention.

I plan to dive into the wiring this weekend. I have a set of schematics for my boat (as it came from the factory but honestly, there lots of wires that have been added over the years). It looks in the prints like the ignition switches were wired in parrallel from the factory, but they almost act like there is a set of sticking relays somewhere but I don't see any on the drawing.

Your clues could same me hours. Thanks in advance.

Mitch

Posted: Thu Jun 04, 2009 11:16 pm
by wowzer52
Both of my lower ign. switches have been replaced for that reason, sticky with corrosion. I also had to replace the 12v fuse panels, among other things. It seems the past owner did not care about moisture in the cabin, no heat, air dryers or anything of that sort. Winters can be damp without ventilation and the electrical had to have alot of work. Switches are cheap but the wiring can be time consuming. However, I sguirted some WD-40 in the flybridge switches and they work well,... for now.

Posted: Thu Jun 04, 2009 11:20 pm
by gjrylands
It sounds like the ignition switches are bad. With a 12v test probe or volt meter you can check the ignition switches. There should be 3 terminals on the back of the switch. One of the terminals will be the power supply for the switch. It will have 12v no mater if the switch is on, off, or start. The ignition terminal will be powered when the switch is either in the on, or start position. The final terminal is the starter terminal. It will be powered only when the switch is in the starting position.

The port switch is not powering the ignition terminal when the switch is in the run position. That’s why it starts, but dies the moment the key is released from the start position. If the switch in the lower helm is in the run position it is supplying the ignition power to the engine. If the engine dies you will be able to restart it from the bridge, because that part of the switch is working. With the lower switch on , you won’t be able to turn the engine off.

The starboard switch occasionally shorts out. When it does the engine cranks, but won’t start, because there is no ignition power going to the engine.

I’m quite sure there is nothing wrong with the wiring. All the problem are due to bad switches.

Posted: Fri Jun 05, 2009 12:02 am
by LandVF36
Thanks for the feedback. Thats what I was guessing as well, but I didn't have a meter or test light last weekend.

I bought a set of Cole Hersee ignitions switches, sealed, all brass and a new set of alarm buzzers for installation at the flybridge helm this weekend. The first thing I planned to do was swap out the switches on the bridge. While digging through the wires under the flybridge dash, I found apair of engine alarm buzzers. You could hear the old buzzers click, but never buzz, so 36 years of moister had gotten to them as well.

Posted: Fri Jun 05, 2009 1:00 am
by gjrylands
I installed a set of pilot lights that light when the alarms buzz. You can buy a small lamp assembly or led from Radio Shack and mount them with the gauges. That way, if you hear a buzzer, a quick glance will tell you which engine has a problem.

Posted: Fri Jun 05, 2009 7:02 am
by prowlersfish
Had the same proplem on my F30 it was the ignition switch . Mine cramked over on there own and burnt up a starter one night . replace the start then found it try to crank over when in the off postion

Posted: Sat Jun 06, 2009 2:53 pm
by LandVF36
Ignition problem solved!

Starboard engine, the upper helm switch was bad. I replaced it and am able to start and stop it without the starter re-engagine. With a meter, I played with the old switch. About 1 in 10 times, when going from "on" to "off", the terminals between B and S (Battery and Starter) would close while the I (Ignition) terminal would stay on.

The Port engine was a little more work. For good measure, I put the new switch in. I could turn over the engine, but it would not stay running. I followed the wires back from the switch to the terminal blocks at the flybridge. They positions and colors don't match the schematic prints I have as the flybridge was removed twice for shipping and somebody was just not thinking... Anyway, I traced the issue back to the wiring at the lower helm. Somone in the last 36 years had fished a coax for a marine radio through that area and hooked one of the ignition wires of a screw connector in the harness between the lower helm ingnition switch and the terminal blocks that feed wires up the upper helm. The crimp terminal was still on the back of the switch and the wire was wrapped around the coax! Took me about 2 hrs to figure it out as there is there is not much room through the access from the bunk room and not a lot of light.

Anyway, now I can safely start and stop the port engine from either the upper or lower helm.

Mitch