Water pressure guage

[wilbur1]

As I stated earlier about raising the motor 2in. I decided to get a manual Jack Plate 4in. set back. I was thinking of also installing a water pressure guage. My ? is can I use the same tubing from the Speedo for the guage as I dont need the Speedo. Or should I just run new tubing? Thanks for any replies.

or do I need to worry about water pressure with cav plate even with top of water? Just dont want to hurt anything.

Thanks again.

[Harper]

I see no reason why you can't use the speedo tubing, as long as you know it's in good condition. Might as well try it out and if it gives you problems, then spend the bucks, time, and scaped knuckles to run a new line.

[ChrigelKarrer]

The water pressure from the pitot tube will show you the water pressure on the lower unit for speed reasons.
But you probably want to know the water pressure inside the engine block.
In this case you need to fit a Tee piece in a water hose coming from the water pump and not from the pitot tube.
Where this hose is depend on your engine.
Chris

[Harper]

The water pressure from the pitot tube will show you the water pressure on the lower unit for speed reasons.
But you probably want to know the water pressure inside the engine block.
In this case you need to fit a Tee piece in a water hose coming from the water pump and not from the pitot tube.
Where this hose is depend on your engine.
Chris

I assumed he knew that, just wanted to use the existing tubing from the motor to the water pressure gauge, hooked properly on both ends.

[wilbur1]

That is correct, Thanks Harper

[Solarman]

The pitot tube as mentioned is not a good indicator of water pressure for preventing harm to the motor. The pitot tube is connected to the gear case at the front of the foot, by the time it tells you you are low on water pressure, your motor Will already be overheating, and the prop will be half out of the water. The water pump intakes are usually higher than the pitot tube inlet (but I could be mistaken on your motor?)?

To prevent overheating, caused by raising motor too high it is best to measure water pressure at the engine block, as mentioned by chrigelkarrer.

Although, I don't think you will be able to manually raise the motor high enough (enough bolt holes?) to get the cavitation plate that high out of the water?

Just some thoughts to consider.

[wilbur1]

What I meant was to disconnect the tube from the foot and guage and connect to the block and water pressure guage. I just wanted to use the tubing itself rather than pull another. I just need to raise 2in. to get the cav plate even with the top of water. You dont think I need a guage when doing that? Just dont want to hurt anything. Thanks

[Solarman]

If the cavitation plate is that low below the water, you would probably not hurt anything raising it that 2". If too high it might cavitate easily/ too frequently, but should still be ok for short test runs. If you aren't sure it's that much below, then you could raise it one bolt hole at a time till you get it right.

Using the speedo tube the way you described is fine, I also didn't understand you were connecting at the motor to read the pressure.

It is not common for qualified dealers installing motors, to leave motors that low in the water, but stranger things have happened.

You will have a considerable difference in how the motor runs when it's at the proper height.

Good luck. Sorry Harper, I read it wrong too. My mistake.

[artdf175]

I am probably getting into this conversation a bit late
however.. the conversation didn't really discuss the your reason for raising the engine height to begin with.
there is a "sticky" thread above that Moonlighter did on setting the engine height and then working on the correct prop (not part of this question)

So if you get the engine height correct.. then you should have no problem with the engine generating sufficient water flow to the heads to keep them cool.
As long as you do the periodic maintenance on the impeller.

the hassle of trying to put in a water pressure gauge is going to far outweigh the benefits, in my opinion. If the engine manufactures thought the water pressure would have been a significant advantage, my thinking is they would have built it in to start with.

Art.