Water pressure gauge installation on Johnson V4 120hp -89

[forsete]

Hi,
Trying to install a water pressure gauge on my Johnson V4 120hp outboard.
Just not sure where to tap it in on the engine.

I found that the connection included in the kit do fit in the threaded holes on the cooling covers (one threaded hole on each side of engine), its just that I don?t know if this is the correct place and the holes are of-course closed in the bottom.. Should I just drill a hole through the bottom or what?..

The arrow in the picture point at the hole that I mention above.

 

[boobie]

Re: Water pressure gauge installation on Johnson V4 120hp -89

Look for a plug on the adapter housing on the STBD side just below the power head.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

Look for a plug on the adapter housing on the STBD side just below the power head.

Thanks. Cant check until next weekend.. But if I dont have the plug you talk about, is this hole I found incorrect?


Thanks!

 

[175se]

Re: Water pressure gauge installation on Johnson V4 120hp -89

boobie is right. that hole you found is for a temp sender, your looking for a plug like he said.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

boobie is right. that hole you found is for a temp sender, your looking for a plug like he said.

Does this exist on my model (1989)? It is equipped with the water control valve, I think this was removed on later models..

 

[175se]

Re: Water pressure gauge installation on Johnson V4 120hp -89

on the stbd side of the exhaust adapter toward the rear -rear of the rubber lower cover mount-yes its on a 1989- the pic (unless my eyes are shot) is on a cyl head, that is not where it goes.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

Still can?t fint this "plug"... Please look at the pics I took of starboard side of engine.
Where should the "plug" be??

Thanks for the help!

 

[boobie]

Re: Water pressure gauge installation on Johnson V4 120hp -89

I guess I was thinking of a later model motor. You have 2 choices. 1, install a tee in that hose and hook it up to your gauge. 2, call the manufacture of the gauge and ask them where they recommend installing it. If you drilled a hole in the top of the heads where those threads are, I don't know what you would run into.

 

[175se]

Re: Water pressure gauge installation on Johnson V4 120hp -89

the third pic there is a plastic elbow with a hose that's where were talking about.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

the third pic there is a plastic elbow with a hose that's where were talking about.

OK thanks, I will try and connect to that hose in the third pic. Hope this will give the correct readings.
I know that on later models they removed the water control valve(?) that this hose leads to on my engine.

I will not drill a hole as I asked about in my first post, thats for sure

Thanks for the help guys!

 

[racerone]

Re: Water pressure gauge installation on Johnson V4 120hp -89

The threaded hles near the thermostat are for a temperature sending unit.----Not a water pressure gauge.-----Water pressure gauge tees into the wee hose for the tell-tale.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

The threaded hles near the thermostat are for a temperature sending unit.----Not a water pressure gauge.-----Water pressure gauge tees into the wee hose for the tell-tale.

The tell tale..? Will that really show correct pressure...? :/

 

[boobie]

Re: Water pressure gauge installation on Johnson V4 120hp -89

The tell tale comes out a pretty big hose in the back of the motor. Racer, how much pressure do you get there ??

 

[cylo]

Re: Water pressure gauge installation on Johnson V4 120hp -89

The tell tale..? Will that really show correct pressure...? :/

I don't think it would either, there wont be any pressure if the end is free flowing.

I could be wrong. But I think you would need to plumb into a line that doesn't connect to the tell tail, if there is one.

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

I guess I was thinking of a later model motor. You have 2 choices. 1, install a tee in that hose and hook it up to your gauge. 2, call the manufacture of the gauge and ask them where they recommend installing it. If you drilled a hole in the top of the heads where those threads are, I don't know what you would run into.

Hooked up the gauge to the hose as suggested, seems to work excellent! Get 1.0 bar at idle. When reving the engine the pressure quickly follows and went up to approximately 1.5 bars at around 2500rpms.

Thanks for the help!

 

[cylo]

Re: Water pressure gauge installation on Johnson V4 120hp -89

Hooked up the gauge to the hose as suggested, seems to work excellent! Get 1.0 bar at idle. When reving the engine the pressure quickly follows and went up to approximately 1.5 bars at around 2500rpms.

Thanks for the help!

That's great! is that the recommended pressure rating for the outboard?

 

[boobie]

Re: Water pressure gauge installation on Johnson V4 120hp -89

What's that in psi ??

 

[forsete]

Re: Water pressure gauge installation on Johnson V4 120hp -89

What's that in psi ??

About 15 psi at idle

 

[boobie]

Re: Water pressure gauge installation on Johnson V4 120hp -89

That pressure sounds real good.

 

[phillnjack2]

Re: Water pressure gauge installation on Johnson V4 120hp -89

ok now with the pressure its definitely wrong to T into the tell tale to get the correct pressure reading.
if you t in, then it wont even give half the reading due to the free water still going out the tell tale pipe.
once you have a pressure guage there is no need for a tell tale that you have to stretch your neck to look at.

simple correct pressure reading will be to use the nipple that comes out and is normally used for tell tale and simply put the
tube on this and then directly to the gauge with no other fittings at all.
all the gauge makers say to put a T piece in, but that is 100% wrong as you will never get the correct pressure if the T goes to
an open end.

whoever first came up with the idea of ting off for this pressure reading obviously did not think this idea through, and now
all the after market gauges says the same.
proves that big company's just jump on the band wagon without even thinking things through as long as they sell !!!!!



phill