Water flow from coolant hole - How much pressure

[Rocketman]

Hey,

What sort of pressure should I expect to come out the wee holes on a Honda 50HP motor. At low RPM's it is a slow dribble, and a constant low pressure flow at high RPM. Iwould think it would flow faster?

[Rob M]

sounds like its time to change the impeller, even at low rpm the water should not dribble out. PS when changing the impeller check the housing

[PeteC]

I agree, there should be more than a dribble, but a steady stream. I replaced my 2001 Honda 50 impeller last Spring and the moderate stream became a stronger stream at idle.

Get the kit that has the impellar housing in case you need to change it also.

[richandlori]

A third confirmation: At idle, I have a solid relatively strong stream of water from my 2004 Honda with about 50 hrs of service. At WOT (wide open throttle) it rushes out with considerable force. I have never seen mine pass just a dribble of water.

I'd get a replacement...

[aya16]

also run a wire through the pee hole first, the salt and silt will build up there and give you a dribble if at all. how old is the pump?
did you ever run the engine without water running through it( flush hose)?
I see guys start their engines on the ramp before they put the boat in the water, gives me chills. If you ever did that then your pump is toast after the first time. But if your pump/engine is pretty new and you never did the above, I would guess the pee hole is restricted.

[Sloop John B]

Yeah, take the cowling off and trace the 'pee flow' back to the block. Probably a black rubber tube, and clear the fixture that feeds this tube with a thin wire.

Consider the motor's history, and maybe it's time to take it in. Just two things in mind: salt water and age.

[Catigale]

I once screwed the hose on to my Bigfoot Merc and twisted the pee hole hose up and ran the motor for a minute at idle before I realised I had no flow.

Two seasons and 500 engine hours ago.

[Harry van der Meer]

There should be a solid stream at idle.

I replaced my impeller two years ago and will do it again before the season starts. It is really no big deal to do it. This is one of the things you do not want to mess with.

[Mark Prouty]

I have had some experience with this problem. I have a 16 foot runabout that can run in very shallow water if I trim the motor up and run full throttle. She'll actually scoot over water only about a 15" deep. Others slow down and get stuck. I live near the Wisconsin River and frequently scoot over sandbars. I can get to a secluded stretch of the river doing this.



On occasion, I misread the river and the boat gets stuck on a sandbar. When this happens, the motor will usually stop peeing.

Here is how I correct the no pee problem on my Mercury 70hp 2 stroke.

There is a little plastic insert with a small diamater hole at the end of the water line. Little grains of sand can block this. I always carry a strong length of wire to poke these grains of sand out. Most of the times this is all that is needed and will cure the problem.

After I poke the pee hole (that sounds painful ), she'll occassionally need to be started and restarted. The stopping and restarting creates just enough force to get the flow going again.

Even at slow idle, I should get a strong flow of water out of the pee hole.

[Greg]

Question:

Do you also replace the thermostat when installing a new impeller?

Greg

[midget]

Catigale-- I had the same thing happen on my Bigfoot. No overheating, but no pee either Turned out the tube feeding the peehole came loose right at the exit inside the motor cover. Merc uses ty-wraps not hose clamps!!

[PeteC]

Greg,

You should check the thermostat while you are in there. My thermostat was somewhat salt encrusted when I checked it last spring. I replaced it and cleaned up the old one that I now keep as a spare.

[opie]

As someone above said, 0n the Honda 50 there is a brass fitting on the engine that screws into the block on one end and has a barbed fitting on the other. The barb connects to the small black hose that leads to the plastic fitting on the cowl, from whence the indicator water stream should flow. My stream was strong, then weak, then stopped, over the course of several hours. I used a coat hanger into the brass barb hole and flow improved. Back on the trailer, I used a deep socket and removed the brass fitting. The screw hole was about 7/16 wide and it was easy to see a piece of scale that was about the size of a paper match wide and 5/16's long. Just the right size to block the water flow. My coat hanger action into the barb was just pushing the blockage aside for a while and not removing it. With the culprit removed, the next day (yesterday on the Cape Fear River) the water stream (pee) was the strongest I have ever had since I bought the boat in Sept. 2006.

[James V]

Please note that the pee hole is not the primary water return for the water pump/impeller. It is just to show that it is working and, as noted, it can clog and you still have water going through the motor. It is best to clean it out either by back flushing or taking apart or as described as above.

[kmclemore]

Many times insects have made small nests in my motor's drain tube, and hence the need to clear it from time to time with some construction wire. In fact, I keep a ready-made piece in my boat's tool kit for just that purpose. Also, the rubber hose - at least the one on the Tohatsu/Nissan motors - is very easily disconnected from the fitting inside the housing, so remove the enclosure and make sure it's connected inside. Not sure if that's true of Honda's, but it bears checking.

The stream, when correct, should look like a 20-year-old guy taking a leak after having a few beers - a steady stream. If it looks like a dribbling 70-year-old guy with prostate trouble, it's time to change the pump!