oil pressure guage for Mercs?

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Thumpbass

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A buddy of mine has a mid 90's Johnson 150 w/oil injection. He says he has an oil pressure guage on his dash so he'll know if is oil pump ever fails. Is there a way to install an oil pressure gauge for a '98 Merc 90ELPTO...been looking though the shop manual and didn't see any reference to such an installation but i couldve over looked something
 
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electricjohn

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Re: oil pressure guage for Mercs?

I have read the Merc shop manual cover to cover many....many times, and I can assure you there is nothing about an oil pressure gauge set up like you describe. Sounds like a good idea and I bet with a little ingenuity it could be rigged up.
 
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Chris1956

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Re: oil pressure guage for Mercs?

I think your friend is either pulling your leg, or is confused about what he has. There is no way to install an oil pressure gauge on an oil injected 2 cycle Johnny. He might mean he has a water pressure gauge.
 
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electricjohn

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Re: oil pressure guage for Mercs?

OK Chris, I though there might be a possibility of T-tapping the line between the oil pump and fuel pump to get a pressure reading, even if it was very low like inchs on the water column.
 
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Chris1956

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Re: oil pressure guage for Mercs?

If you tap the oil line on the Johnny, You may get a vacuum reading, however, you introduce a possibility of an air leak which would be a real problem.

If you put a pressure gauge on the oil line of a Merc, you might see some pressure (5PSI??), however, the motor already has a no oil alarm.
 
Silvertip

Silvertip

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Re: oil pressure guage for Mercs?

What the gentleman probably has is a tach or speedometer that has the three "system check" idiot lights in it. The tach is the gauge. The idiot lights are simply part of it. They do not provide a visual PSI reading. The simply light to indicate an oil or overheat situation.
 
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Thumpbass

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Re: oil pressure guage for Mercs?

Chris1956 said:
If you tap the oil line on the Johnny, You may get a vacuum reading, however, you introduce a possibility of an air leak which would be a real problem.

If you put a pressure gauge on the oil line of a Merc, you might see some pressure (5PSI??), however, the motor already has a no oil alarm.
Click to expand...

the no oil alarm is just an indicator that the tank is low though, correct? it wouldnt sound if the level was full but the pump failed, right? wish there were a way to be re-assured that the oil injection system was working...
 
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Chris1956

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Re: oil pressure guage for Mercs?

I think the Mercs have a no oil alarm which watches to see if the pump is pumping oil. You might look it up in a service manual.
 
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electricjohn

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Re: oil pressure guage for Mercs?

The Merc V-6's have a prox sensor on the oil pump shaft linked to the oil alert system, but the I-3's and 4's just have a low level alarm.
 
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