Confusing electrical problem

Bob James

Bob James

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May 3, 2008
190
Catalina 310 Catawba Island
This problem raised its ugly head this past weekend - the buzzer on the key switch would not shut off and the tach would not work or would stick at some rpm. I could silence the buzzer by turning the key switch off. No issues with the engine running (gravity feed) and restart was fine so I assume lift pump running OK. After I finished sailing for the weekend and found my wiring diagram (at home - stupid) and it looks like either the 10 amp circuit breaker at the cockpit engine panel or the 20 amp CB on the engine are in the circuit for the key switch. I did not reset either one at the time. Previously when the 20 amp CB was not working (need to replace) the engine would not reset. Do you sparkies think it is a simple reset or is there something else to check out.
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
The buzzer is an indicator for engine over heat or low oil pressure.
Places I would start to inspect:
  1. Low on Oil
  2. Infrared Temp check of engine at sensor and general engine locations.
  3. bad connection to sensors (oil pressure sender, or temperature sender)
  4. corrosion on the key switch
  5. corrosion on the circuit breakers
  6. corrosion in the wires connected to the buzzer
  7. bad ground connection - also possible corrosion.
 
valcour

valcour

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Mar 6, 2008
331
Catalina 310 Scott Creek, VA
The spade connector on the oil pressure switch below the oil pressure sender down on the port side is known to vibrate/break off. This will cause the buzzer to run even if you do have good oil pressure. This would be my first check, I learned this after a failure on my 2003 model.
 
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Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
the tack AND the buzzer are the key. You have wires that are rubbing on an engine part and the insulation is gone. the buzzer is turned on by the oil pressure, water temp, or amp output switch on the engine being grounded. it is normally open. a bare wire touching the engine accomplishes the same thing. turn on the ignition and after determining which circuit it is (oil, water or amps) disconnect that wire from its engine sensor switch (not the gauge sender, the idiot light switch sensor) The buzzer should still sound if there is a bare wire. start at the sensor switch and wiggle the wires till the buzzer stops. closely inspect the wires in that area. My bet is it will be near the tack sender as that is also acting up (probably for the same reason)
 
KZW

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Do you have a picture of the oil sensor location?
 
valcour

valcour

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Mar 6, 2008
331
Catalina 310 Scott Creek, VA
The oil pressure swiitch is down low, aft of the alternator. You almost need to remove the engine box cover to get back on to it. You will see three wires (on my boat all painted grey) going to the two terminals. The switch is part 13 right below the sender part 6. This is shown on page 50 of the universal parts list.
 
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KZW

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
The PO painted the engine on my boat, all are silver/grey. That doesn't help in tracing issues. My parts manual and yours seem to be different. Page 50 on mine is the Fresh Water Cooling System.
 
KZW

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Is the green wire in the picture a ground wire?
?
 
marchem

marchem

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Nov 16, 2012
1,038
Catalina 310, 2000, #31 31 Santa Cruz
KZW, I'm pretty sure the green wire (and the larger cable behind it) are ground wires. The oil switch is in the center, with two spade connectors on the right side. You can also see a 90 and 45 elbow coming off the same port, which can be used for an oil pressure sender. It's not too bad to reach around and work on those parts, especially if you've got skinny arms!
 
KZW

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Rob,

Thanks for the information. I'm having issues with my low oil horn and tach. Both are intermittent. I open the engine compartment, wiggle the wires, and sometimes they work again. The Tach gets a signal. On start it goes to 3,000 RPM. Push the throttle up and it pegs high. The horn works when 12 VDC is applied at the pedestal. I suspect a ground and have been trying to track it down for months. Alas, the PO painted the engine before I bought it, so now all wires are silver-gray. I've been trying to trace, one by one, using an ohm meter, with limited success.

Alas, nothing about me can be considered skinny.
 
B

Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Either you have an engine problem or the wiring harness from engine to control panel has developed a short. Visually check the harness in the bends around fiberglass corners for chaffed insulation.
 
marchem

marchem

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Nov 16, 2012
1,038
Catalina 310, 2000, #31 31 Santa Cruz
KZW said:
Rob,

Thanks for the information. I'm having issues with my low oil horn and tach. Both are intermittent.

Alas, nothing about me can be considered skinny.
Click to expand
Intermittent is the worst...

You need to find a skinny friend!:)
 
pk104

pk104

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Jun 30, 2009
207
Catalina 310 Atwood Lake
I have replaced the oil sending switch because the spade broke off. I also replaced the female connector. Before that was done the connection would vibrate loose.
In the engine control panel at the helm, I had to replace the buzzer and the starter push button which I found to be corroded but couldn't the corrosion until I took it apart.

What gave me the most trouble was the wire connection strip in the engine control panel. I would have interminant problems that I couldn't find. I would check the wires connected to it and think they were fine. Once I replaced that strip those problems disappeared.
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
You are not alone Gary. Your experience happens more often then anyone will admit. The sin of plastic parts is they often hide corroded metal within. Good on Ya for continuing to follow the isssue till you solved the problem.
 
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marchem

marchem

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Nov 16, 2012
1,038
Catalina 310, 2000, #31 31 Santa Cruz
pk104 said:
I have replaced the oil sending switch because the spade broke off. I also replaced the female connector. Before that was done the connection would vibrate loose.
In the engine control panel at the helm, I had to replace the buzzer and the starter push button which I found to be corroded but couldn't the corrosion until I took it apart.

What gave me the most trouble was the wire connection strip in the engine control panel. I would have interminant problems that I couldn't find. I would check the wires connected to it and think they were fine. Once I replaced that strip those problems disappeared.
Click to expand
Gary, did you replace the strip with the same style, a terminal strip with proper crimped connections, or just butt splice the wires together? That project is on my to do list, but I haven't decided between a solid terminal strip or butt connection.
 
jssailem

jssailem

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Oct 22, 2014
21,088
CAL 35 Cruiser #21 moored EVERETT WA
Rob. Do yourself and your future owners a favor and use the terminal strip with heatshrink ring connections.
 
marchem

marchem

.
Nov 16, 2012
1,038
Catalina 310, 2000, #31 31 Santa Cruz
jssailem said:
Rob. Do yourself and your future owners a favor and use the terminal strip with heatshrink ring connections.
Click to expand
I was leaning that way, but I know people who have used butt connections as the most secure and robust option. At least until you have to disconnect something!!
 
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