Catalina 34

General Activities => Main Message Board => Topic started by: Patches on January 28, 2019, 10:28:50 PM

Title: Fuel Pump to Ignition Switch Wiring for M25XP
Post by: Patches on January 28, 2019, 10:28:50 PM
My apologies in advance for the simplicity of this question, but I can't locate the answer from any wiring diagrams i've seen.

I have the M25xp engine, circa 1990, and am replacing the engine panel and wiring harness (both from CD).  I tossed the terminal strip and butt connected the harness to the new panel wires with marine heat shrink connectors.  I have suspended and secured the harness so that the weight of the harness is is supported--not by the butt connectors--but by securing the harness to the aft panel of the port lazarette.

My fuel pump is activated by a separate red wire which runs from the ignition switch on the panel.  I know because I removed it from the old panel.  And that's my problem because I don't remember which post I removed it from on the old ignition switch. Doh!

The switch on the new CD panel--like the old one-- has "on" and a "momentary" key positions, the latter which you hold to heat the glow plugs.  The "on" looks to be fed by the #10 "panel feed" wire off the solenoid "+".   The "momentary" looks to be fed by a white #10 which goes to the glow plugs.

Is the red wire to the fuel pump supposed to attach to the post on the ignition switch with the red wire (on), or the post with the white wire (momentary)?  My thought is to the same as the "red" (on) because that would mean it runs any time the panel is (1) "on" or (2) when engine is running.  If connected to the white (momentary) then the fuel pump would only pump if I was trying to preheat glow plugs.  But alas, my thoughts when it comes to things electrical are often "off."

Thanks in advance for your replies.

Patches   

Title: Re: Fuel Pump to Ignition Switch Wiring for M25XP
Post by: scgunner on January 29, 2019, 08:12:15 AM
     Patches,

        If I recall correctly the ignition switch is an automotive type, on and crank(momentary)which is not used because Catalina put a stand alone starter button on the panel. Where ever you connect the fuel pump wire it should be on and pumping when the ignition switch is turned to the on position.
Title: Re: Fuel Pump to Ignition Switch Wiring for M25XP
Post by: KWKloeber on January 29, 2019, 08:40:30 AM
P-

See wire #9 on the schematic on pg 30 of the XP Parts List manual, on the Wiki under "manuals"  **see note below
https://c34.org/wikiwp/

I don't like "loading up" the key switch, so I re-do a panel I put such things on anything that is made hot by the key -- hot side of gauges, hot side of a switch, etc.

The fuel pump wire is actually redundant -- both the alternator field excite (purple wire) and fuel pump feed are made hot by the key switch.  With new harnesses, I run one #14 wire and branch off in the engine compartment.  I have also fabbed a sort of dual terminal that plugs into the alt field excite male terminal and branches back to the fuel pump, but the fuel pump wire could be "hard tapped" as well.

[Edit - To prevent failure at panel terminals,] I create a harness bundle and zip-tie it to the back of the panel (typically to 2 gauge brackets and the tach) with zip ties. See Pic.

** As a new owner you need to know the dirty little secret about the engine vs. the boat.  The engine as purchased (and it's wiring) is just popped into the boat.  Manuals from Universal/Westerbeke are typically NOT personalized to Catalinas.  For instance panel schematics shown are typically for a Universal/Westerbeke panel, not a Seaward panel.  Note that the key/start/preheat wiring may be different from yours (besides being different from Universal's panels, Seaward itself had different panel wirings.)  It's sometimes like a box of chocolates-- for example, the wire color can change from the panel to the harness to the engine (handy!) And colors used have varied from one harness to another.

-k
Title: Re: Fuel Pump to Ignition Switch Wiring for M25XP
Post by: Ron Hill on January 29, 2019, 01:40:46 PM
Patches : Attach the fuel pump wire to the "ON" pole of you switch.  Your glow plugs should be on the "Momentary" (spring loaded) pole.
If you haven't done it you might want to look at the "glow plug solenoid" upgrade.

A few thoughts
Title: Re: Fuel Pump to Ignition Switch Wiring for M25XP
Post by: Patches on January 30, 2019, 12:32:27 PM
Thank you for your replies!  Will attach to the "on" pole of the switch where the panel feed (red #10) wire connects.