water pressure guage hookup

[racefan2]

I am trying to install a water pressure guage on my 1991 20HP Evinrude as it is on A CMC Tilt and trim with a 6 inch setback and 3 inch rise so I just wanter to monitor the water pressure. I though it just went in the pisser hose but I see it has to go into the water jacket in the block. I do not see anything in the service manual. Can someone give me a hand here with this install before I cut the hole in the dash.

 

[Silvertip]

Re: water pressure guage hookup

What do the instructions say! Most simply "T" into the tell tale.

 

[AguaSki]

Re: water pressure guage hookup

I did not use all the hardware that came with my water pressure kit. Instead I used a "T" fitting sold at hardware stores for landscape drip lines and connected off the tell tale line. I also used a sealant to confirm the "T" connection was strong. This method may mess with the water pressure accuracy on the gauge, but I am more concerned with seeing fluctuations in pressure and not an accurate pressure reading.

 

[racefan2]

Re: water pressure guage hookup

The instructions don't tell you anything for a OMC. It just tells you to drill a hole to get hose out of motor. I am going to tap into the tell tale with a brass elbow out of the block with two fittings one for each size hose. I just picked up a fitting but it did not clear a lug so I have to get a extention peice to get the elobw back 1" back. I will post results in a few days.

Thank you for your help.

 

[rickdb1boat]

Re: water pressure guage hookup

You are on the right track, Racefan.....8)

 

[Silvertip]

Re: water pressure guage hookup

The purpose of the pressure gauge is note deviation from normal. In other words, install the gauge, install a new impeller and then note pressure at idle and wide open throttle. In the future, any deviation from those readings indicates impeller degradation. My 75 HP Merc idles at 7psi and runs 17 psi at WOT. It is "T'd" into the tell tale.

 

[racefan2]

Re: water pressure guage hookup

Well I cut a small peice of hose off and tried it today as it is raining and going to for 2 more days so it will be a while before I even get it mounted in dash. I had about 3 to 4 lbs at idle on muffs and went up to about 12 at speed not WOT. Notice the word did as my day blocked the teltale with his finger and now after that I have no water pressure at idle 0 and it jumps all over the place at speed and jumps as the rpms do and it does it every time you start the motor. I cannot get it to work right at all now. The tel tale has good flow and the pressure guage is on the straight pass through of the tale and the overflow is on the side outlet of the T.

I just gave it another try and I put the gauge in the end of the tel tale and there was no were for the water to go but into the gauge and I have 0 water pressure as the gauge does not move at all and at 3000RPM I have 3lbs out the teltale but remove the gauge and it will shoot the water 7 feet from the motor. I also used the T and the water shoots out of the open side and if you block it the gauge does not move at all. It is like the gauge in blocked not letting water in as I cannot beleive 0 pressure with water going into the gauge.
Well I guess I have to make the 2 hour drive down the highway to return the water presure guage now:'(

 

[Silvertip]

Re: water pressure guage hookup

Water does not actually get into the gauge. Water however does compress the air thats in the line. Your Dads finger over the tall tale probably didn't damage the gauge either. I'm wondering if a piece of debris didn't plug the gauge. I assume you have a 0 - 30 psi gauge. I doubt holding a finger over the tell tale would raise the pressure that high.

 

[racefan2]

Re: water pressure guage hookup

Yes it is a vector Teleflex 0 - 30. It only went to 14lbs but when he released it (teltale the gauge dropped to 0 instantly and that is where it sits.

What could I use on it. Would a low pressure air pump clean it out? I took the fitting off the gauge and it was clean.

 

[roscoe]

Re: water pressure guage hookup

Suspect the hose is plugged.
Disconnect the hose from the motor and the gauge, then blow thru it.

 

[racefan2]

Re: water pressure guage hookup

I tried that as it is just a 12 inch peice of hose and it flows water fine without the gauge. I connected the guage directly into the teltale in the bottom end with no other place for the water to go but into the gauge directly and got 0 water pressure.:|


After a lot of reading with a search of water pressure I see the gauge works off of air so I blew into the hose on gauge and it went uo so I am going to cut the teltale tomarrow 4" up and install the white T and run hose off of that and see what I get. Will post later tomarrow results.

 

[racefan2]

Re: water pressure guage hookup

I just called teleflex and was told to use the branch off of the T and I gave it a try and I get a reading now of about 7lbs at 2500 RPM and 1 to 0 at idle. I beleive I need a new impeller but it will have to wait a few weeks as a friend just drove 18 hours to fish the next two weeks with me so there is no way I am taking a chance of pulling it apart and getting into a major problem and ruein his two weeks.

 

[Silvertip]

Re: water pressure guage hookup

Those numbers sound low. An impeller change is not a major operation and since you suspect it is already going bad, it may leave you without water pressure when you need it most -- in the middle of your two weeks of fishing. And then you may try to poke along back to the dock and overheat the engine. Just playing devils advocate!

 

[racefan2]

Re: water pressure guage hookup

I will look at my service manual at the impeller and water pump change.

I also beleive I have a bad gauge also as I still have 0 water pressure and no water pressure reading till about 1100 rpm then it jumps up and when you go to idle it drops to about 1/2 lb then after 5 seconds it drops to 0. Even the man at teleflex said you should have a reading if you have water going through the teltale. He also said no water should get to the gauge and I know there was water in the lines going to the gauge so maybe I did get some water in the gauge. I will call teleflex tomarrow and see if they can change my gauge out.

 

[racefan2]

Re: water pressure guage hookup

This is driving me batty as I removed everything again today and streached out the hose and made sure no kinks and reinstalled everything. The first 30 seconds of motor running I had 2lbs then wam it dropped to 0 and it never moved till I got to 900 RPM this time.

I will put a whole water pump in the motor just in case it is accurate. Tomarrow it will be in a lake for a full water WOT test.

 

[racefan2]

Re: water pressure guage hookup

Well just got home and do not have good news about the pressures. I have 0 pressure till I get to 1400RPM now and then it only goes to 3 lbs and at WOT on tach ? 4500 RPM I only have 7 lbs. Watet pump and impeller or bad gauge :^

 

[Silvertip]

Re: water pressure guage hookup

What pressure do you get if you plumb the gauge directly to the port and eliminate the telltale? If the readings are still low, it is apparent you need an impeller. Actually, that's a good idea anyway. This provides you with a benchmark pressure reading so in the future, any deviation from that reading is an indication something is amiss. Without a new impeller, you have no idea what normal is.

 

[ricksrster]

Re: water pressure guage hookup

Silvertip is right. My normal is 6 PSI at WOT. Amanual I have says at WOT you want at least 5 PSI Through ant manuveur.

 

[racefan2]

Re: water pressure guage hookup

If you block the teltale I get the same thing no pressure at idle and nothing when you rev it on muffs.

I have a new gauge on order as teleflex said there qauges are not taped shut for security and this gauge was and it is not available in stores and I got it hanging on a peg so it was returned so it may have been dropped or who knows what . Cabelas replaced it for me at no shipping charges since it should not have been put back out to sell when it was returned and then sold at full price, so I will switch gauge out and try again. Telefley said the normay from a 20 should be ballpark 3 lbs at idle 12 lb WOT.

I am ordering a whole water pump assembly and changing it out or just having it done as I know I do not have great water pressure and I do not want to cook a motor.

 

[Silvertip]

Re: water pressure guage hookup

Very wise move. Keep us posted.