36 MKII Oil Pressure Alarm

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pa3csm
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36 MKII Oil Pressure Alarm

Hi i have a question about te oil pressure alarm when i start the engine it gone off,  but some times after time it wil beep  ​gently
if i change te engine rpm to lower or hire speed it stop sounding stop but after time it wil beep again gently​ ??

Hi i saw  the switch open en see  green  copper corosion gives transitional resistance so i buy e new one 

Jan Borst

Perseid
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Hi-
I am looking for some help with oil pressure alarm. 2002 36 mkll, M35B, After running engine 12 hours I arrived at destination, while idling to wait for bridge opening, oil pressure alarm goes off. I shut down engine, check oil, levels are fine, no oil in pan, all appears fine. Restart engine, oil alarm sounds immediately. I proceed to run engine to get boat under bridge and into port. I Recheck oil levels and such, all is still good. I then let boat sit and cool, two hours later alarm sounds immediately when I turn the key. I am thinking they sending unit is bad. Any thoughts on the subject. This is night three of a 2 week vacation trip.
thanks.
 

Bob & Kim Kissel
s/v "Full Circle"
2002 36 MKII Hull# 2084
Wing Keel, Tall Rig, In Mast Furling, M-35B
Lake Michigan

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Siler Starum
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Hi Bob&Kim,

The LO-pressure sensor caused us serious problems whilst we were in busy trafic passing one of the busiest locks in the Frisian Riviera as the FO-lift pump stopped working, no fuel and no power anymore.
Turned out that on our Siler (#2013) the power supply for this FO-lift pump is in series with this sensor. You can check this by putting contact "on" and the pump shoudl give already a ticking sound. Presume this should be on your C36MKII the same.
I bypassed this sensor now for the time being.... we were day 2 on our vacation, and continue

 

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

Perseid
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Joined: 9/23/16
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Update-
Once the engine cooled and I was able to do some investigating I found that one of the spade connectors on the oil pressure switch was broken. This opened the circuit and caused the alarm. Currently I have the OP switch bypassed until a new on can be installed. I was able to order a switch for next day delivery and will install tomorrow. 
 

Bob & Kim Kissel
s/v "Full Circle"
2002 36 MKII Hull# 2084
Wing Keel, Tall Rig, In Mast Furling, M-35B
Lake Michigan

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Siler Starum
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Great to hear that you found the problem as well and luckely for you that you didn't faced fuel supply issues causing the motor to stop what we had. Also the connection on our LOP-switch was found broken with making "touch-contact" because of some cable-ties.
Also weard that we didn't had the alarm-buzzer sounding although sometimes when switching the contact to "on" before starting and after stoppping it works. So I believe that we are facing an interesting challenge to answer the question "how should it actually be....." 
General question therefore: what is actually the good electrical diagram for the Universal M35B engine ( I found several different versions)
 

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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LeslieTroyer
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The best diagram is the one that matches your boat!! Depending on what you or previous owners have done nothing may match. The oil press switch works by grounding the alarm circuit if there is low pressure. On newer universal engines it also shuts off the lift pump (to stop the engine - problematic). You shouldn’t use any thread sealer when installing the new one. Les

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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Siler Starum
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Posts: 113

Thanks for clarification that newer models Universal (like ours) have the "safety-stop" function (without override and pre-warning).
For sure an item to put on the worklist to modify for the winter when I have SILER in my "man-cave" on the hard.  

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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LeslieTroyer
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Notice the word problematic. My engine will run fine without the lift pump to about 1/2 tank. Yours may run longer as your fuel tank is higher than mine. Les

Les & Trish Troyer
Mahalo 
Everett, WA
1983 C-36 Hull #0094
C-36 MK 1 Technical Editor. 

Commodore

 

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Siler Starum
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Posts: 113

Indeed our tank is somewhat above the engine, but the suction from our tank is not direct from the bottom but witjh a suction-pipe through the top of the tank to the filter/water separator and then to the lift-pump. 
Therefore the gravity will not work in our situation and is the lift-pump needed to get fuel.

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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Haro
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Posts: 403

Jan, I had a problem with my pressure switch a while back. I am posting all the pertinent images and a wiring diagram to help explain the related circuit.
You can buy the pressure switch form any auto store. There are 2 types. The one you want has normally open contacts - that is when there is no oil pressure the contacts are open. It closes when the oil pressure reaches 5 PSI or higher. This closed contacts places a short across the soanalert so there is no voltage across it - so no more sound. It provides power to the fuel pump. So when the oil pressure drops the contacts open, the soanalert sounds and the fuel pump quits running and the engine turns off to protect the engine. The switch requires a special deep socket for installation.
If you feel there is no problem with the oil pressure - you can by-pass the switch with the use of a jumper wire placed on the harness to simulate closed contact position

You can find more info and be able to download the original engine manual from my link on my signature.

 

 

 

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