'95 Evinrude 9.9, Pin Hole in Copper Water Pipe

[JDusza]

I am repairing a '05 9.9 that overheated. You have seen my recent posts.

As I am cleaning and rebuilding I find something I did not expect.

In the copper water tube coming from the water pump to the engine, I find a 1 mm hole about 2 inches below the engine end.
Is this hole design intent? It is very clean as if tooled and not rough as if from corrosion.
I have not noticed this before.

Thank you,
Jim

 

[raczekp1]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

my 9.9 made in 81' has the same small hole in water pipe just below it enters to the block.
i think its to cool/clean any oily residue from exhoust tube, drive shaft.when engin operates this hole crates pee strean on exhoust tube

 

[boobie]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

The hole was put in by the manufacture.

 

[JDusza]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

Thank you!

 

[the machinist]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

OK, enlighten me. Are you sure it is the water inlet pipe to the powerhead? Why would they divert inlet water to do this purpose & loose pressure to the block when the outlet water will have just the same cooling effect. And they are already diverting the early water off for the tell tale indicator.

I have never seen this hole in any I have had apart from 74 to 94. And I just checked 2 parts motors (late 70s or early 80s) in the shop to be sure & no hole. However the outlet tube from the block has changed many times. And I am sure that I have not seen them all. Some (the early motors) have no tube, others the tube can be from 8" down to 4" & just empty into the exhaust housing doing any cooling.

 

[raczekp1]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

Hi LeeRoy.
i can sand you a photo of this water tube and smal hole in it. this hole is located on pipe just 1 or 2" belowe pipe entrance to exhoust tube

 

[F_R]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

Many motors have a drilled hole in the water tube. It is there to cause a water spray to cool the exhaust. If not cooled, the exhaust can melt the plastic water pump housing.

Not all motors have the hole in the water tube though. Many have a coolant discharge somewhere else to do the same job.

 

[the machinist]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

Yes, Racz please send it to me. However there is a hole in the later 9.9 & 15hp round "tuned" exhaust tubes. It is down 2.73" or 72mm from the powerhead.

 

[raczekp1]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

today i will make a photo and send you by mail.
its from 9.9 81' short shaft

 

[Haffiman]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

When the engine is running at low rpm's, the thermostat hardly opens. Closed thermostat means no water in the exhaust. To be sure of 'some' cooling the hole is there. If running at low rpm in cold conditions the engine might look 'steaming' out of the upper exhaust hole. This is steam from the exhaust tube spray-cooling.
The pee-hole/hose has a similar intention. With closed thermostat no water cooling the exhaust cover unless you have a constant circulation. The main intention is to cool the cover and as an ad-on you get a water flow indicator.

 

[raczekp1]

Re: '95 Evinrude 9.9, Pin Hole in Copper Water Pipe

9.9 83' water pipe and hole