Engine gauges that will automatically shut down the engine at presets ? Re oil press

[Milacron]

what is yours set at ? I have Murphy A20P-150 oil pressure gauges, the direct mechanical one in the engine room failed recently, need to replace it, and wondering what to set the engine shutdown trip at for oil pressure for 12v71TA.


http://www.fwmurphy.com/products/gages-mechanical-%E2%80%93-pressure/20p-25p-series

[davidwigler]

I'm not sure I would want automatic shutdown. A loud warning buzzer would permit me to turn the boat in a safe direction before shutting down. An automatic shutdown at the wrong moment could be a disaster.

[Milacron]

I'm not sure I would want automatic shutdown. A loud warning buzzer would permit me to turn the boat in a safe direction before shutting down. An automatic shutdown at the wrong moment could be a disaster. Yeah I thought about that too. It is possible my gauges are wired for alarm only and not shutdown....I should remove a wire and find out (I say remove, rather than short, as I think the gauge trip contact on the P models is N.C.)

Note the more elaborate PABS models incorporate "pre alarm" possibilities before the shutdown. PABS models have N.C. and N.O. contacts.

Having said all that, there may be situations where as long as you have two engines, automatic shutdown of one of them is worth the risk. A sudden loss of oil pressure might ruin a 12v71TA ($45,000 for overhaul !) in the short time you spent turning the boat...which you could still turn on one engine in most cases. (in nearly all cases, if you have bow thruster)

[tonytrakovich]

I also would not do an automatic shutdown. Not only will a low oil pressure shut you down, but a malfunction in the alarm electrical can shut you down. A sender failure. Low or loss of battery power. I like the loud alarm idea best.

My $0.02

[MikeP]

Totally agree. An automatic shutdown is the last thing I would ever want on an engine. I was not aware that such a thing actually existed! :(

If it does, what the heck are they thinking?

[Milacron]

If it does, what the heck are they thinking? They might have been thinking more in terms of an unattended land based generator or such. But as I said earlier, maybe better to have the shutdown if you've got another engine to keep going on, than to have to spend megabucks and time to rebuild an engine that is ruined within seconds of no oil pressure. Better of course to have the pre alarm system so you have some indication the shutdown is going to happen real soon.

That would be good also to have time to glance at your other oil pressure gauge (at inside helm or flybridge) to see if you are really at no oil pressure or it's just the gauge. If both gauges, working off different systems (one direct mechanical, the other indirect electrical) at at no oil pressure, and you don't shut down pretty quick, the prime mover is going to seize and shut down no matter what.