Water pressure sender installation

[Lazlo24]

I'm about to install a water pressure gauge on my 130 Beto -95. Found a used Yamaha gauge that says kg/cm2 instead of psi and since I'm European that's nice.
Bought the sender tube from my local Yamaha dealer and found that there is a little brass restriction in each end of the hose. Since the tube is to long is it ok to simply cut the hose in the gauge end and discard of the restriction in that end? Does anyone have any installation instructions to a WPG?

[boscoe99]

Isn't the restrictor just at one end? Should be at the motor.

Cut the tubing to fit at the gauge end and reinstall the ferrule. You will then have all that you need.

But having said this, and to answer your question, yes you can simply cut and discard the restrictor if you so choose. At both ends if there is one at each end.

[rodbolt17]

NO NO NO
DO NOT DISCARD.
it is NOT a restrictor.

it prevents the ferrul from simply crushing the plastic.
without that metal insert tube failure is guaranteed.
then ya got a water sprayum tube that coats the motor.

look at how the ferrule (compression fitting) works.
all will be clear.

[boscoe99]

He is correct. I forgot.

[Lazlo24]

I'm an idiot! That's just simple plumbing, got my head stuck on the very tiny hole in the "support sleeve". Thanks for your answers. I'll find a way to put the brass support sleeve back when I have cut the hose. I'll make the cut at the gauge end, at least I'll notice me feet getting wet when it starts leaking due to poor installation......

[rodbolt17]

it is easy peasy.
use the grinder to almost hit that brass.
do it on several sides.
remove the insert.

cut the tube to length.

lightly heat the tubing.
reinsert that brass part.

pay attention and tignten it down.

[Lazlo24]

Finally found the time to install it. Have only tried it at idle and revving without gear but I can't get any reading. If I remove the pipe at the engine end there is plenty of water. It's tight trough the cowling but the pipe moves when I pull it in either direction. When I remove it at the gauge end I can't see water travel trough the pipe. Are you suppose too be able too blow air with your mouth trough it? Any ideas?

[almetelo]

On my F100 I don´t have any water pressure at idle either and I guess none will show water pressure at idle.

The water pressure didn´t worked as I expected.

Did you bleed the system?

For me water pressure (mainly) and water/coolant temperature gauges was a wast of money.

[boscoe99]

It is quite common on almost all water pressure gauges that when connected to a Yamaha they will indicate zero psi. Or kg/cm2 in your case.

Water should never be flowing through the tube. Water pressure from the motor is going to create air pressure in the tube. When the pressure gets high enough the needle will indicate pressure. If there is water flowing through the tube there is a problemo.

Put the motor in the water and then run the boat at some considerable RPM. Say 3500/4000. You might then see the needle respond.

In my case the water pressure gauge was very worthwhile. With a new water pump I would see ABC pressure at my normal cruise RPM of 4000. After several years of use the pressure I would see at 4000 RPM would be less. I knew then it was time to change the water pump impeller.

[Lazlo24]

Almetelo
No I didn't bleed it. I figure that even if the air compresses it's a closed system (if it doesn't leak) with the instrument at one end and a "water lid" in the other end so it will still work, the only thing that will change is the length the water will travel in the engine side of the tube depending on pressure. Besides even if a run the motor with the gauge side open there is still no water flowing trough the pipe. What's your pressure reading at WOT?

Boscoe99
I guess I have to make a proper test run. The boats is in the water but the weather is not in my favor. I was only surprised to see zero respond even thought I revved the engine in neutral. I'll post an update after a test run.
The main reason I got it is preparations for putting a lift on the boat so I'm more interested of readings at higher rpms anyway

Thanks for your replies

[boscoe99]

I thought summer and boating season in Sweden would be over by now. Particularly in northern Sweden.

How are you doing with all of the mid-easterners heading your way? As they say in Italy, "what a messa".

[Lazlo24]

The season is coming to an end but I still got some time of work. The boat will be out of the water by next weekend so the installation I'm doing now is mainly for Summer's to come. I'll see if I can mange to post a picture of the installation.

The calamity around the refugees is slowly settling but since Sweden has taken in most refugees per capita in Europe (I think) there are still plenty of problems to deal with.....

[pstephens46]

Almetelo
No I didn't bleed it. I figure that even if the air compresses it's a closed system (if it doesn't leak) with the instrument at one end and a "water lid" in the other end so it will still work, the only thing that will change is the length the water will travel in the engine side of the tube depending on pressure. Besides even if a run the motor with the gauge side open there is still no water flowing trough the pipe. What's your pressure reading at WOT?

Boscoe99
I guess I have to make a proper test run. The boats is in the water but the weather is not in my favor. I was only surprised to see zero respond even thought I revved the engine in neutral. I'll post an update after a test run.
The main reason I got it is preparations for putting a lift on the boat so I'm more interested of readings at higher rpms anyway

Thanks for your replies

What type of lift are you referring to?

What a bummer! Boating season over in mid August....

[Lazlo24]

Engine lift.
Yeah it sucks but this is the summerhouse boat. My brother in law has his boat in the water until first ice comes around December but that requires a cabin and a big heater

[Lazlo24]

Found it! I had managed to twist the plastic tube upon installation. I run everything from the engine cowling trough the splashwell in a big hose and that's why I didn't saw it yesterday. Now the gauge shows a low reading at idle and jumps to 1,5 bar (20psi) when I rev it. The only thing left now is to connect the FMM to the GPS instead of the speedo and move the compass light cables. Bought everything early in the spring to have time to install it til this Summer. Yeah right the summer is over and the boat goes out of the water next week......