58 35hp RDE-19C Shut down issue

[Antonino]

Hi,
My 1958 35hp RDE-19C is equiped with a key start, pushbutton electric choke, mercury
safety switch and vacuum safety switch. I'm reasonably confident everything is wired correctly according to a
schematic diagram I have. The engine starts, runs, and I can shut it down with either the manual or electric
choke. It will not, however, shut down when I turn the key switch to off. I can disconnect the kill wires coming
off the points and short them to ground to kill the spark. When hooked to the "M" terminals on the key switch,
the engine continues running when the switch is in the off position. With the kill wires disconnected from the key
switch, there is continuity between the two "M" terminals with the key in the off position. If there is continuity
between the "M" terminals with the switch off, why aren't the points shorted in the off position when the kill wires
are hooked up to the switch? The kill wire for the upper cylinder goes directly from the key switch "M" terminal
to the point set for the upper cylinder. The kill wire for the lower cylinder goes to the vacuum safety switch then
to the other "M" terminal on the key switch. I've been struggling with this for over a week. The easy way out would
be to "bag it" and use either the manual or electric choke to kill the engine, but now I'm on a mission and would love
to figure this out and have the engine shut down when the switch is in the off position. Any wizards out there who
can help me???
P.S. I have good ground between the switch box and the powerhead via the harness, and continuity on the kill wires
to the "M" terminals. The vacuum switch is functional - I can short the lower point set by grounding the switch.

Thanks in advance
Antonino

 

[HighTrim]

Re: 58 35hp RDE-19C Shut down issue

Sounds like you have a good understanding of what is going on.

All that I can deduce is that the key switch is not functioning for whatever reason, even though it "tests" like it is. Have you tried another switch?

 

[Antonino]

Re: 58 35hp RDE-19C Shut down issue

Hi Chris, Thanks for the reply.

No I haven't tried a different switch, but I'm going to call my supplier in a short while and talk
to him about it. Perhaps we can determine if I have the correct switch for my application. Its acting
like it needs a ground somewhere in the off position. When I put an ohmeter on the switch lugs, it tests
like it should when I go through the three switch positions.

 

[oldboat1]

Re: 58 35hp RDE-19C Shut down issue

Antonino ? I was going to ask you whether your motor was originally set up for a push button starter and p.b. choke, but thought I would check and see. I did see a parts diagram on that other site that showed a key switch (OEM apparently available, as well as a Sierra aftermarket.) You might do a search here on iBoats for threads on your motor ? found one (2009) that deals with a kill switch, or lack of one.

Anyway, your switch wiring looked right to me, but haven?t verified with a model-specific diagram. I did come up with an Intertec diagram that shows a connection from the M switch post directly to the magneto, and the second M post connected to the cutoff switch and thereby to the magneto (think that is the setup you have.) As part of the loop to the cutoff switch though, there is also a grounded connection to the mercury switch, which in turn goes to one of the small posts on the solenoid. Maybe that is the link that is needed in your wiring setup.

Hope this helps.

Curt

 

[HighTrim]

Re: 58 35hp RDE-19C Shut down issue

here is the wiring diagram.

 

[oldboat1]

Re: 58 35hp RDE-19C Shut down issue

better diagram. From you description, appears you have it wired correctly, Antonino. Possibly an electrical issue with the vacuum switch?

 

[HighTrim]

Re: 58 35hp RDE-19C Shut down issue

He can kill the motor by grounding the 2 black leads leading to M terminals. Sounds simply like key switch is not doing its job somehow.

 

[oldboat1]

Re: 58 35hp RDE-19C Shut down issue

Thanks. see now that was noted. Maybe a spray or two of electrical cleaner in the key switch wouldn't hurt, but then there is already continuity between the M poles. I would want to bypass that blasted vacuum switch and connect directly from the switch to the magneto wire for that lower cylinder. Just stubborn. Dinner time.

edit: maybe already has continuity with the vacuum switch bypassed(?)

 

[Antonino]

Re: 58 35hp RDE-19C Shut down issue

Ah, Wizards all. thanks guys. All good advice. Sorry for the delayed response but I've been in the garage working on
you know what!! The wiring diagram sent by Chris is the one I have been using. I have no idea what this motor was originally
set up for. When I bought it, there were two harnesses in the owners garage. One wasn't worth taking home, and the other had a
white switch box that appeared to match the motor - so thats the one I took. I know some of the engines had a pushbutton start, and
a pushbutton choke. Others had the key switch, and some of the motors had the generator/ammeter options. given that, some of the
harnesses had all the wires installed - regardless of which options were installed. I couldn't ask the owner because he had passed away and his son was selling everything. And given that, I just started at the beginning tracing all the wires through the connector
on the motor and through the connector on the boat side to the switch and key boxes. First sign of trouble was that the kill wire for the
upper cylinder, didn't feed through connectors to the boat side. Got around that by running the kill wire for the upper cylinder to one of
the unused wires for the generator kit that my motor doesn't have to an "M" terminal on the key switch. But that still didn't solve the kill problem. The motor had a vacuum switch on it, but no mercury switch which got a little confusing. I found a Mercury switch and installed it per the wiring diagram. No help there - the kill on switch off still didn't work. The key switch looks rather new and is an OMC factory switch which I was able to buy a new key for. Despite my consternation that it tested good but didn't work, I assumed it was ok based on its cosmetic condition.
When all else failed, I disconnected the kill wires at the powerhead and jumpered them the ends together and confirmed that the kill wires were wired to the points correctly. Via testing, I knew the vac. and mercury switches were ok, so I hooked everything back up according to the diagram and felt that something wasn't closing the loop. So with a jumper, I ended up coming off the center post of the vacuum switch to the "M" terminal of the the upper cylinder kill wire and VOILA!! it worked. Ok, so now all I need to do is tie
into the second unused generator kit wire and I can it through the harness as well. Nice try - that second wire has no feedthrough
to the boat side of the harness. Perhaps its physical damage in the harness - who knows, I'll just run a separate wire - or both wires externally but will need to get a connector in there somewhere so the kill wires can be disconnected when the harness is disconnected.
Long answer, but you guys took the time to help so I hope I gave you a worthy answer. Thanks again.. Antonino

 

[HighTrim]

Re: 58 35hp RDE-19C Shut down issue

Did you originally have 2 black wires coming out from under the mag plate? Or just one?

 

[Antonino]

Re: 58 35hp RDE-19C Shut down issue

Originally and still - have two black wires exiting the mag plate. One (the upper cyl) goes directly to
a "M" terminal on the key switch, the other goes to the Vacuum switch then to the other "M" terminal.