Water pressure gauge connection 225 efi

hdl

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My water pressure gauges are not working. Is ok to disconnect them from the gauge and blow out the tube or do I need to disconnect from the motor also? The tube appears to go into the block at the back and I can not remove the fitting. The motors are Merc 2000 225 efi's. Suggestions?????
 

Texasmark

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Re: Water pressure gauge connection 225 efi

Put the engine on muffs, disconnect what you want and run it. You'll have your answer.

Mark
 

gss036

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Re: Water pressure gauge connection 225 efi

If you run the motors with the hose disconnected at the gauge you will fill the line with water. That would probably ruin the gauges ( when reconnected) as they are designed to run on "air pressure".
It is unusual to have both stop working at the same time. Are the lines pinched somewhere?
I am not that familiar with the newer engines, but I would think you can access the lines coming out of the engines by removing part of the engine covers. and blow backwards to remove the water. Could it be possible that they are full of water all the way to the gauges and the gauges are full of water?
 

Texasmark

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Re: Water pressure gauge connection 225 efi

If you run the motors with the hose disconnected at the gauge you will fill the line with water. That would probably ruin the gauges ( when reconnected) as they are designed to run on "air pressure".
It is unusual to have both stop working at the same time. Are the lines pinched somewhere?
I am not that familiar with the newer engines, but I would think you can access the lines coming out of the engines by removing part of the engine covers. and blow backwards to remove the water. Could it be possible that they are full of water all the way to the gauges and the gauges are full of water?

Let's back the truck up. There is no mechanism that insures how far up the tube water advances. Actually water will work the meter mechanism and will do so much more accurately than air as water does not compress and air does. The metering mechanism has no idea as to what is applying pressure to it.

The metering mechanism is usually a closed brass semicircle and the meter needle is attached to it. Deflection of the brass chamber (semicircle) causes the needle to deflect.

Removing water pressure from the system allows any water in the system to make it's way out of the system via hydroscophic disposition, meaning that over time, gravity will pull on the water and it will be displaced by air as it makes it's way to the lowest point in the circuit, or exits depending upon the exit route. In the case of loops or dips, the water remains and just goes along for the ride with the trapped air in the circuit.

Mark
 

emckelvy

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Re: Water pressure gauge connection 225 efi

No one has yet answered the original question which was whether or not anything bad would happen if the gageline(s) were disconnected up front and air blown back thru the motors, in an effort to check/clear the lines.

The answer is, "no". All you'd be doing in that case is blowing air back into a water passage and that ain't gonna hurt nuthin'.

HTH..........ed
 

Dukedog

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Re: Water pressure gauge connection 225 efi

Ed pretty much answered tha question.

Could it be possible that they are full of water all the way to the gauges and the gauges are full of water?

But this puzzles me. I've never seen a water pressure guage tha worked without water to tha guage. Pull tha little tube off tha back of tha guage. Hold it between your legs. Start tha motor :eek:...................:confused:

Maybe tha NEW stuff uses electric? Donno?
 

gss036

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Re: Water pressure gauge connection 225 efi

I guess I have been told wrong info on the water pressure guage operation. I was told that water would compress the air in the line and work the gauge and that water should not make it all the way to gauge. Goes to show you what I know.
 

Dukedog

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Re: Water pressure gauge connection 225 efi

Understand! That does happen. Just a little infomation. On our hot rod motors we "bleed" tha water pressure tube ta make sure ta get a really accurate reading at first start up. Now its a habit with any motor.
........D
 

gss036

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Re: Water pressure gauge connection 225 efi

I did a GOOGLE and found this article from another board, mixed feelings there also about water.no water to gauge.
Last post of the article: Usually you find only air in the line. If there is even a slight air leak in the feed hose at the gauge (or internal to the gauge,) water will eventually fill the line and can get into the gauge. The gauge will still work, but if it is in freezing temps-the ice will probably damage the gauge bladder and it will either not work right next year, or will read incorrectly. If you have any concerns, pull the line off the gauge when you put it up for the winter and blow any water back into the engine. I ran mine with no fall maintenance for 9 years, then over one winter the gauge froze and it had to be replaced the next spring. Perhaps an internal leak in the bladder. It went thru last winter with no maint and was fine this past spring.
http://forums.screamandfly.com/forums/showthread.php?t=203613
 

Dukedog

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Re: Water pressure gauge connection 225 efi

I think where tha confusion comes inta play is some are refering to tha mechanical parts in tha HEAD if you lose tha seal. Donno? We've been doin' it tha way I described for lotsa years with no problems other than losin' a seal and gettin' water to tha mechanical parts of tha guage. A tiny bit of air in tha tube is no big deal but you get a lot in it you will get funny pressures. ie. motor borderline to high you get air through tha intakes intermittenly causes tha pressure to drop, jump around and/or peg tha guage. No air its rock steady from low ta high. Thats why we do what we do. When ya got a motor makin' 8lbs (yes, thats 8 pounds) at 9 grand plus it leaves little room error. Think we're all on tha same page just tha way it gets worded is a little different.............:)
 

hdl

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Re: Water pressure gauge connection 2000 225 efi

Re: Water pressure gauge connection 2000 225 efi

Thanks for all the replies. I found a small connection at the front of the motors that allowed me to pull the tube apart. This left about 2 feet of air tube going back to the motor and the other end was about 15' going to the gauge. I blew out the long run to the gauge (disconnected) with compressed air and it blew a "fog" of moisture and salt that litterally filled the cabin, next I blew out the short run back to the motor, repeated on this on both motors, hooked up and works perfect.

I'm glad I found the connection in front of the motor because it was unbelievable the "fog" that came out of both hoses. Probably wouldn't hurt the motors but sure was a bunch of fog. ;)
 

Texasmark

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Re: Water pressure gauge connection 225 efi

Apparently this "crud" had plugged your line and prevented pressure from getting to the gauge.

Glad you had a happy ending....that's what this is all about isn't it.

Mark
 
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