page describes C34 owners' solenoid for glow plugs upgrade
Solenoid for Glow Plugs
The installation of a solenoid to the glow plug circuit will
reduce the time to hold the key or push button that powers the
glow plugs preheating the engine before starting. Shorter,
larger wires = more power to the glow plugs!
Solenoid, 12v, O.E.M. Quality Solenoid Ford Starter
Solenoid SW3 STD # SS581, Niehoff #FF143A or Wells #F-496
Six feet of #8 wire
Three large stud round wire connectors (#8) for
starter (1) and solenoid studs (2)
One small stud round wire connectors (#8) glow plug
Grounding wire, two feet #14 wire with end connectors
Two bolts, nuts and washers
1: Mount solenoid with its mounting flange
tabs. Most solenoids have two tabs with holes for mounting.
These tabs must be grounded for the solenoid to work.
Fabricate a plate or find close to matching mounting bolts on
the rear of the engine. This was not possible on my M25 so I
mounted mine UNDER the fiberglass/wood lip that the engine
hatch rests on, above and rear of the engine. This means that
it is hanging upside down over the rear of the engine. Two
bolts were used to mount it, using one of the bolts to connect
the ground wire that is wired to the ground on the engine.
2: Remove white (I think its white) wire from last
glow plug. This is the wire that goes up the wire harness to
the glow plug switch. DO NOT cut the end off the wire to make
it shorter. If you ever have a problem with the solenoid, then
you can connect the system back the way it was. Connect this
white wire to the small stud on the solenoid. Some solenoids
have two small studs. One is not used. Before installing,
ground the solenoid and touch a hot wire to the small studs
one at a time. One of them will make the solenoid CLICK. That
is the one you connect the white wire to.
3: Connect the (+) side of the starter to one large
stud on the solenoid. Use the #8 wire, cut to size with the
end connectors crimped or soldered in place.
4: Connect the other large stud on the solenoid to
the glow plug where the white wire was removed. Use the #8
wire, cut to size with the end connectors crimped or soldered
in place, one large and one small connector.
5: Go to engine panel, turn on key and push the glow
plug switch and you should hear a click of the solenoid down
by the engine. Hold for 25 sec, shut key off and return to
engine and see if you can burn your finger on the top of a
glow plug. It still should feel hot. I now hold the push
button for only 12 sec instead of 25 to start the engine.
Comments: The engine panel is fused, so the control
of the solenoid is but the (+) from the starter through the
solenoid to plugs is not. This is a problem if the solenoid
should malfunction and remain HOT. You will burn out your glow
plugs because you will not notice they are on. I have never
heard of this happening but I have a safety light that I have
added for this.
Safety Light: Purchase a 12v low amp auto, 1/4 inch,
dash light that you mount in the engine control panel. Ground
one side of the light at the panel and run a #14 or #18 wire
down to the top of a glow plug or that side of the solenoid.
When you hold the glow plug push switch on, the glow plugs and
the dash light will both be on. Release the button and they
both go off.
(Capt Al) #55
I have a few more ideas to add to Al's procedure. If
you have a M25XP engine, you can mount the solenoid thru the
bolts that hold the heat exchanger in place - it saves a lot
of work. As I mentioned in the Aug.97 Mainsheet on
this topic, don't cut the old wire. If the solenoid
fails, you can always connect it back to its original wiring.
Take a #2 pencil and spiral the wire around it to take up the
slack If you want, you can mount a safety light, but you
already have a ready made indicator on the engine instrument
panel to let you know if the glow plugs are engaged and when
they are disengaged -- it's the voltmeter. When you
engage the glow plug switch, the voltmeter will immediately
drop about 1+ volts. When you release the glow plug
switch, you will see the voltage go back up.
This should be a good enough check as to whether the solenoid
is working or whether it is stuck. I have always found, the
majority of the cost is in time doing the work. As I
mentioned in that Mainsheet article, if I had to do mine
over again, I wouldn't skimp and use a Napa Ford starter
solenoid for $13.99, I'd use a marine grade West Marine
solenoid for $19.95. The marine grade is probably a more
reliable solenoid in the long run.
Here's the wiring diagram that Stu sketched.
Important: The opinions expressed here are those
of the individual contributors to this page, and not those of
the Catalina 34 National Association or Catalina Yachts, Inc.
Additionally, this material has not been reviewed by Catalina
Yachts, Inc. for technical accuracy. This page's maintainer
cannot guarantee the accuracy of this information or the
desirability of suggested modifications or upgrades. Please
obtain assistance from a competent marine mechanic or boatyard
prior to making any significant modifications to your vessel.