Oil Pressure/Temp Alarm Sounds with Batteries On

[JoyRide2.0]

This is new and, I imagine, could be related to my need to replace that damn wiring harness. At any rate, I thought I might post here to see what the peanut gallery has to say.
Basically, turn on the batteries and the alarm sounds. No key in the ignition, no nothing. Put in the key, turn to "on" and the alarm continues as normal. Turn the key to light up the glow plus, and it works (voltage drops as expected). Press the starter button, the beast roars to life, and the alarm stops as expected. I've checked the connections at either end and they seem fine. (Man, that oil pressure sensor is a bear to get to.) Could it be something as simple as a bad switch? Any thoughts. And thanks, you guys are great.

Kirk
JoyRide
1990 #1173
M-25XP

[Noah]

What engine model?

[waughoo]

Might be getting a short in one of the trailer plugs causing power to be supplied when the key is off.  The short might also be at the key switch.  That's where I would start looking.

[KWKloeber]

Kirk

Engine?  Put it in your signature to help us help you.
I suspect it's an XP, but...


After shutdown, the alarm will sound (until/unless the battery is disconnected)?

-kk

[Ron Hill]

Kirk : You've got a short in the oil pressure wire. It's energized by the battery switch !!

A thought

[JoyRide2.0]

Sorry guys, DUH! M-25XP
When it runs, the alarm goes off. Shut it down and it starts back up (as it should). Pull the key and the alarms keeps a buzzing.

Kirk
JoyRide #1173 1990
M-25XP

[KWKloeber]

My best guess is that the alarm on the panel is being powered by other than the key switch ON position (I terminal.)

Pull the panel and with a multimeter make sure the power to the alarm isn't hot all the time.

The switch I terminal might be hot all the time - if so replace it.  Is it an OFF—IGN—Start?  Of OFF—ACC—IGN—START?

[KWKloeber]

Kirk : You've got a short in the oil pressure wire. It's energized by the battery switch rather then the key switch!!

I don't believe so, if you mean the OP sender wire is shorted to ground — the alarm would still sound when the engine develops pressure.  And the key switch OFF would silence the alarm.

Either the power to the alarm is miswired or as Alex said the key switch is bad.  But if the switch is bad the entire panel would be energized not just the alarm.

Kirk - are the panel gauges/lights operate correctly w/ the key?
If so, I'll bet a case of Stu's best Scotch that the alarm is powered by the key switch B terminal rather than the I terminal.

[Ron Hill]

Kirk : Unless a PO change your key switch it should be  =  OFF - Ignition (ON) - Momentary (glow plugs)

A thought

[Stu Jackson]

Not necessarily true, Ron.  When my 1986 key switch died a few years ago, I replaced it with an On/Off, because I have a separate glow plug button.  The switch that was there was three position but only one post in the back was wired and that was from the factory.  Obviously Mark IIs are different.

[Ron Hill]

Stu : Yes, The original Catalina Engine Panel wiring for the 1986 and 1987 & maybe early 1988 C34s?, had two push button switches.  One for the starter and one for the glow plugs!! The ignition was a simple ON/OFF key switch.  The 1988 and subsequent C34 have the 3 position key switches and a
single pushbutton for the starter!!

I believe that a PO of your C34 added a 3 position (on/off/spring loaded glow plugs) ignition key switch, but only wired in the ignition because there already was a separate glow plug push button switch.   My guess??   

A few thoughts

[KWKloeber]

We MUST remember that, in the heyday of boat building, sometimes CTY (and Universal, and Seward) had to install whatever components were available.  There's no doubt in my mind that some panels received Off-Run-Start switches when they needed only a Off-Run switch.  There's no reason my M-25 had an 202M-15 seawater pump other than that's what they could get their hands on, rather than a 202M-15.

[Ron Hill]

Ken : The early C34s had an engine instrument panel was made by Bristol Marine and the 3 position ignition (from the 2 position) switch didn't come in to the production line until the 1988 production (and the appropriate change to the Engine Panel & Owners Manual).  Then all subsequent C34 have the 3 position ignition switch.

I believe the Catalina changed to Seaward for engine panels in the 1989 or 1990 C34 production.

A few thoughts

[KWKloeber]

Ken : The early C34s had an engine instrument panel was made by Bristol Marine and the 3 position ignition (from the 2 position) switch didn't come in to the production line until the 1988 production (and the appropriate change to the Engine Panel & Owners Manual).  Then all subsequent C34 have the 3 position ignition switch.

A few thoughts

Yes, I know about Bristol panels and Start being on the key switch.  I  have a Bristol. 

My comment was in reference to why, on an '88 (Stu's "Off-On (only) panel ) there could be a 3-position switch.

So I don't understand your comment -- are you saying that, if Seaward's supplier had no 2-position switches available, they would just stop making panels -- and not install a 3-position switch (wired as Stu's)? 
Not on a bet.  Just like when Oshkosh couldn't get the 202M-15 pump they didn't tell Frank they had to stop building engines -- they installed a 202M-07 as on my M-25.   

[Ron Hill]

Guys : I believe that Catalina just wanted to make sure that the changes to the engine instrument panel matched the instructions in the Owners manual!
Key switch momentary for the glow plugs or the separate push button panel switch.

A thought