Starter Push Buttons - Beware!

[brankin]

The Perkins Prima M60 has a switchable diode in the alternator that will allow for the starter switch to go to ground and allow the starter to engage. As the engine starts and spins up the alternator, the diode will switch the lead from negative to positive thus killing the starting circuit since both sides of the switch are positive. This prevents the starter from engaging until the rpms drop the voltage to a point where it will switch the diode back to negative. It is an easy conversion for any alternator shop but just remember that if the circuit is dead and the starter will not engage, you have a shot diode. Have the alternator rig the diode to you can field replace the diode.

[skipmac]

Originally Posted by svHyLyte

Skip--

If the starter sticks while engaged shoot happens so fast that one has little time to respond. A warning light as Bill describes would be wise as one would know to shut the engine down as quickly as possible. I tried, but could not because the power surge killed the shut-off solenoid at the injection pump and I did not then know enough about the engine to know how to shut it down manually. I do now and everyone should learn how to do so when they first get their boats/engines. I also have a manual kill cable rigged for use in extremis. The warning light is a good suggestion and I will look into it.

FWIW...

In that case the only thing fast enough to save the battery and wiring would be a fuse. Wouldn't help the starter but at least reduce the chance of a fire. Have you looked at the Bluesea battery terminal fuse block? I will be installing those on my house and start banks. Guess I will be adding the warning light as well. Good thing I have a spare starter.

[sailorboy1]

Originally Posted by Dennis.G

Good quality push buttons cost much more than $5. A more industrial type moisture proof switch is a smart investment compared to cheap Radio Shack type gear.

Yes I have since looked them up and found the marine ones and they are $13.95.

Thanks

[sailorboy1]

Originally Posted by David M

If you don't want junk, then get the Cole-Hersee's with the brass bodies. They cost 15 bucks but that is less expensive than a new starter motor. They are very corrosion resistant.

The old switch that went bad is a Cole Hersee. Now I don't know if Seaward used a marine one when they built the panels for Hunter (apparently all the 400 series boats use the Seaward PN3410 panel) or if Seaward/Hunter saved the $1 to get the regular one that looks the same.

Far as the other questions:
yes the system has a relay in it so the actual load for the starter coil is only about 8" long
Maybe an idiot light would have helped I would think a starter could survive 30 seconds of current (is was over 10 minutes from the time of my starting the engine and smelling the problem), but just how many of these type things can one plan for before you are way too paranoid

I think I will replace my stop switch at the same time as now that I think about it I know if it stuck my engine wouldn't start (but I could work around that except if I needed the engine NOW in a danger condition).

[sailorboy1]

So replaced the starter and the start push button. I thought the warning light was a reasonable low cost idea. So while doing the switch I looked to see if there was roon in the panel. Well it turns out there already is a warning light and I just never had really taken note of it. So since it doesn't work I checked the bulb and guess what; there isn't any bulb. And there's a plastic filler piece in there so I guess there never has been a bulb in the holder.

Go figure!

[Lake-Effect]

Originally Posted by brankin

The Perkins Prima M60 has a switchable diode in the alternator that will allow for the starter switch to go to ground and allow the starter to engage. As the engine starts and spins up the alternator, the diode will switch the lead from negative to positive thus killing the starting circuit since both sides of the switch are positive. This prevents the starter from engaging until the rpms drop the voltage to a point where it will switch the diode back to negative. It is an easy conversion for any alternator shop but just remember that if the circuit is dead and the starter will not engage, you have a shot diode. Have the alternator rig the diode to you can field replace the diode.

Great idea.

It's disheartening that this start switch fail happens so often on boats, but seldom on autos, which are started and run alot more often. My 87 Jeep did it ONCE, when it's exposed, firewall-mounted starter solenoid stuck closed. Design fail.