1987 Johnson 150 water pressure gauge?

[MMarshall88]

I have a 1987 Johnson 150 GT. I recently installed a water pressure gauge on the boat and I wasn't sure exactly to tie off the line too. I've heard from some to tie it into the telltail and eliminate it. My question to that would be , if I cut that telltail off, where does the water go besides to the gauge. I thought the water had to exit out the back of the Block? My other idea was to tie a T fitting into it and have the water go to the gauge and out the telltail. But would that elimatw some pressure that the gauge will read. If anyone has done this or have a idea to use, please let know. Thanks.

 

[boobie]

On that motor the only thing I know of is to T it in to the telltale. Maybe somebody will chime in with better ideas.

 

[MMarshall88]

That's the way I have it at this present moment. I haven't got to take it out on the lake yet but I ran it on the hose outside earlier and it was showing about 5 psi on idle. The water pump was replaced on it last year so I'm not sure what psi its supposed to be at

 

[1983 ercoa 21']

On my 150xp the tattle tail was unhooked and gauge hose put in place.

 

[MMarshall88]

If it's unhooked , then where does the water go. I thought the water had to exit the motor. I may be wrong and confused

 

[Bosunsmate]

Most of the water like 95% goes down and out the exhaust channel out the back of the motor.
To confuse things more for you those telltales are often used to bleed air out of the motor so if you blocked it off straight to the gauge then you risk getting airbubbles and a hot spot in the engine.
Now i havent worked on that motor so i will have to finish by saying i dont know whether that is applicable to yours or not:frusty:

 

[MMarshall88]

Well I know my motor has a fitting at the bottom of the exhaust block from the water comes out to the tell tail or pee stream. I have it hooked up right now with a T fitting. So I'll be able to test it next week when I take it to the lake. But I thought it would be a problem if I blocked it off and had the water run straight to the gauge. I was really under the assumption that water had to exit.

 

[gm280]

Well I know my motor has a fitting at the bottom of the exhaust block from the water comes out to the tell tail or pee stream. I have it hooked up right now with a T fitting. So I'll be able to test it next week when I take it to the lake. But I thought it would be a problem if I blocked it off and had the water run straight to the gauge. I was really under the assumption that water had to exit.

A pee tube isn't the only place water exits any OB engine. There are other channels/passages for it to go and exit. If you look at the exhaust, you should see water misting out with the exhaust too... Pee tubes allows the operator to visibly see if the water pump is working. Even a water pressure gauge doesn't guarantee you that you have proper water flow through your engine. It merely tells you that you have some pressure. But you water passages could be totally blocked and not flowing and the water pressure gauge will still show pressure. I like the pee tube better for that reason. JMHO!

 

[emdsapmgr]

My concern for teeing into the telltale line is that it may affect the total pressure reading on the new gauge. I run my water pressure gauges direct to the telltale hose barb and eliminate the telltale. Guess I'm concerned that if the telltale is bleeding off some pressure, that the gauge may read somewhat lower than if it's just plumbed direct.

 

[MMarshall88]

I ran the boat today on the lake . I put the line with a T fitting. At idle it was ablout 5 to 7 psi. And at top speed it was 13 -16 psi. So I'm assuming that's around the right pressure it's supposed to be

 

[emdsapmgr]

Mine runs over 18 at WOT. My idle pressure is around 7. On a brand new impeller.

 

[MMarshall88]

That's pretty close to mine. Which I have a T on my lines so I have water pushing to The gauge and out the telltail