---

Hello, I bought the subject line boat before winter and have just about got it and the trailer ready to tow to the water. The biggest problem I have is that the hose coming from the motor to the console water pressure gauge has crumbled to pieces. I was able to fish a line from the console to the starboard aft access so running a new hose shouldn't be a big problem. The problem is that I cannot find a replacement hose assembly. It is swaged at both ends. Can I just get a similar hose and tie wrap it to new fittings? Also, does water actually flow thru the hose or is it air pressure converted by the sensor on the motor? Appreciate any help I can get on this.

---

Water flows to the gauge and it is the pressure that the gauge reads.

The hose is sold by the foot. The fittings and zip ties should be available online or at a Mercury dealer (not cheap). 1/8 diameter I recall. Check Home Depot/Lowes.





Questions?

---

Thanks for the info Phil T. I found that the tubing can be withdrawn from the fittings, so they can be reused. Hopefully I found the correct 2.5 x 4 replacement hose used on my boat on Grainger's website. If it is the right stuff, I'll post the part number here. It's also clear tubing which will be good for seeing any salt water blockage in the tube.

---

So I needed a replacement water pressure hose for my Montauk 170. I ordered Metric Polyurethane Tubing, 4mm outside, 2.5mm inside diameter tubing from Grainger's. It works perfectly plus its a translucent blue so its easier to see if water is flowing through it. The PN is 1PBR3. You get 100' but you'll need less than 25' for a 17' Montauk. Cheers

---

I have the same model year and same issue. My tube was pinched and broke near the engine. I spliced in about 1 foot of tubing with quick connectors but the gauge doesn't work. There is no water leak.

Do you need to de air the tube? (i.e) Does the water go right to the gauge?

---

Yes

---

Should i disconnect from gauge, run engine until air is out then replug into gauge?
Or is there some other way? Can't imagine salt water does good thing to the gauges.

---

I assume the original poster has a Montauk with a 4-stroke Mercury engine on it. These engines did come equipped with a water pressure gauge, probably the Mercury "Flagship" line.

Mercury's gauge line does not use the stardard hose tubing that the generic brands use, also used by all speedometers, and instead uses a very small diameter "swizzle stick" looking black plastic tubing. This, in turn, requires special compression type fittings at both the engine end and are standard on the gauge itself. This special water pressure gauge tubing is only available from a Mercury dealer.

On both speedometer and water pressure gauges, water DOES NOT flow up to the gauge. If it did, the gauge would quickly fail from corrosion. From the water source, water flows only partially into the tubing, compressing the air in front of it, which then activates the gauge.
These gauges are all activated directly by compressed air pressure, not water itself.

Mercury's branded water pressure gauge kits all come with the correct compression fittings and small diameter plastic tubing. I believe the very small I.D tubing is used because it provides a more accurate reading of engine water pressure.

---

Hello, I recently went through a similar issue with a new-to-me 2011 170 Montauk with a 90hp EFI engine. The water pressure gauge tube had crumbled where it had been exposed to the weather near the engine. A dealer quoted me a price of about $70 for a replacement tube, but had some trouble verifying the part number. After some additional research I decided to purchase a complete OEM gauge kit, Mercury part number 79-895288A05, price was $46.80 plus $8.00 shipping from an eBay source. The kit includes a new gauge, tubing, and a variety of fittings and miscellaneous parts to fit several different engines.

Knowing what I know now, I could have just purchased new tubing, as a previous poster mentions. Google polyurethane 4 mm X 2.5 mm tubing and you will find many sources. This tubing is commonly used for pneumatic applications, you would not need to buy it from Mercury. The tubing included in my kit was marked as:

SUN-RISE POLYURETHANE TUBE O.D. 4mm I.D. 2.5mm W.P 120PSI

The fittings are also commonly used for pneumatic applications, the kit I purchased included the same style fittings that were used on the original installation . . . the tubing enters the fitting through a colored ring, just press in on the ring and you can withdraw the tubing from the fitting (as mention by a previous poster).