1989 Evinrude 175 Crossflow - Pressure Gauge Problem

[azhunter]

Hello,

My water pressure gage doesn't work properly and hasn't since I've owned the boat. Before putting in a new OEM water pump assembly this weekend, the pressure gage would read zero unless I plugged the tell tale with my finger; then it would come up a little bit. I was hoping that after the replacement it would work like it should but it doesn't. It still reads zero unless I plug the tell tale. It definately reads more pressure now than before but it is still not working properly.

The gage is "t'd" off the tell tale line. The line for the gage is considerably smaller than that of the tell tale line. Is this the problem? Do I need to reduce the tell tale line size or is the tell tale itself suppose to have some resrtiction (kinda like a garden drip system or something)? The attached picture shows where the line comes out at the bottom of the exhaust plate. Unfortunately, this is the best picture I have right now but can post others tonight when I get home if needed. Any help is greatly appreciated. Thanks.

 

[ezeke]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

The interior ID of all of the fittings, the outlet on the exhaust housing, the "T", and the tell tale in the floor of the lower cowl should all be 1/8".

In addition the whole system should have the tell-tale hose routed up to the top of the number one cylinder and back down so that air does not bleed up into the cooling system.

The tell-tale hose on this V4, is about right.

The OMC instructions said to have the gauge "T" four inches from the exhaust cover outlet nipple.

 

[Dhadley]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

You have it T'd in correctly. If the overboard line isn't showing much coming out you may need to blow backwards thru the line as it may be plugged. If the overbaord line is clear the hose going forward may be pinched.

 

[azhunter]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

Thank you guys for your responses. I will check the ID of the hoses and also re-route them as shown in the illustration by ezeke. I will also check them to make sure they are not piched or otherwise obstructed.

If this doesn't solve the problem, is it ok to plug the tell tale? As I mentioned, the gauge seems to work with it plugged. I would rather have a gauge working in front of me than a tell tale behind me that I can't see.

Thanks again!

 

[emdsapmgr]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

It is not unusual for the pressure gauge to read lower on a "T'd" line. I run my gauge direct to the engine's nipple for that reason. Have you verified that the gauge is calibrated properly? I know you are from the south, but freezing can affect the gauge bladder and it's readings. On a new impeller, normal idle is 6-7 lbs and high speed pressures should be around 16-18.

 

[azhunter]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

It is not unusual for the pressure gauge to read lower on a "T'd" line. I run my gauge direct to the engine's nipple for that reason. Have you verified that the gauge is calibrated properly? I know you are from the south, but freezing can affect the gauge bladder and it's readings. On a new impeller, normal idle is 6-7 lbs and high speed pressures should be around 16-18.

I have not verified the calibration of the gauge but that would seem to be a good idea if I should be operating at 6-7 lbs at an idle because when I plugged the line, my gauge read around 12-15 lbs. Could I check the gauge myself by using a regulated air source?

Did you have to by-pass the tell tale to run your gauge direct or is there another spot on the engine that I could hook my gauge to?

thanks.

 

[emdsapmgr]

Re: 1989 Evinrude 175 Crossflow - Pressure Gauge Problem

I don't have a telltale -the gauge hose goes direct to the engine. Why not hook your gauge direct, run the engine and see what gauge readings you get. (A gauge that does not return to zero when off, can be out of adjustment.) You could check the gauge with limited air pressure if you had another good one that you could compare to.