1955 evinrude 25 hp does not seem to pump water

[cbouchard]

I am in need of some expert opinions/direction relative to subject motor. Got the motor running after rebuilding carb, new ignition components, new seals in the lower unit and a new impeller. Took it to the lake today and got it started with mo problem but saw no evidence of water pumping.....I believe on these motors the water is supposed to discharge from the upper exhaust port on the mid section.....really not far above the pump itself. Nothing was coming out so went back to the garage to double check that I had the water tube correctly inserted into the pump outlet. Wasn't sure if it was or wasn't but when I put it hack together I made sure that it was inserted correctly into the rubber grommet surrounding the pump outlet. Put it in the test barrel and still no water coming out. Took it apart again and put the lower unit into the test tank and ran it using a 1/2 inch drill....water was coming out of the outlet.....decent flow of water but not squirting up hight which I attribute to the fact that the drill I had has a gear reduction on it and actually turned over quite slowly. I believe that with the rpm of the engine it would pump with a lot of pressure. Next thing I did was to blow air up the water tube and felt air coming out to the exhaust which I suspected. I then took the garden hose nozzle and squirted water up the tube.....again water came out of the exhaust. Water might have been coming out of another spot up toward the motor nut not sure because the hose was spraying a lot of water. Put it all back together making sure that the water tube was connected to the pump properly and guess what.........NO WATER WAS COMING OUT OF THE EXHAUSEt....shut it down because I didn't want to take a chance of overheating things and went for a drink...Can anyone help me out. Thanks, Cliff

 

[F_R]

It might surprise you that running it with a drill means very little. Reason: In actual use, the pump is surrounded by exhaust under pressure. If exhaust gets into the pump, no or little pumping. When dinking around with a drill, there is no exhaust.

 

[54bobby]

can't pull up a schematic for that motor right now but does it use a pin in the drive shaft to turn the impeller? if so, is yours missing or broke?

 

[Chris1956]

Usually those motors spit water out the port high on the midsection, after the thermostat opens, at least that how it works on the '58 - mid 60s era Big Twin motors.

I would stick a meat thermometer up the exhaust port and look for 140* water temp.

 

[cbouch]

I don’t believe it has a thermostat. In 1955 things were very basic. There is no pin going thru the driveshaft for the impeller..there appears to be a little pin protruding from one side and it looks to be solidly in there. Relative to the exhaust gases surrounding the pump on this motor shouldn’t the exhaust be taking a different route, like down the exhaust port which exits in the center of the midsection . That being said the whole inside of the midsection seems to be loaded with oil..like exhaust oil that comes from a 24:1 mix. I am wondering if exhaust is blowing out of the pump water intake..is that possible?? Thanks, cliff

 

[racerone]

No thermostat on those.----But there has to be pin to drive the impeller.----The water in your test bucket must be 6" above the pump.

 

[cbouch]

There is a pin and it firmly holds the impeller I do not think that is a problem. The tank that I have brings the water just even to the pump...definitely not 6 inches above it. The only place that I can get that is in the lake. Will try it. Question for f_r. Your comment relative to the exhaust was that in respect to a prop that has exhaust thru it??mine does not. Thanks everyone for your help. Still chugging away at it. Cliff

 

[F_R]

Listen up---The whole exhaust housing is full of exhaust when it is running. It blows out the big hole aft of the propeller. That hole half way up us only an exhaust relief port to make it easier to start and idle better.

 

[cbouch]

Ok thanks so where is the cooling water supposed to flow out of.. same place as the exhaust??and only in the upper spot as a relief??

 

[F_R]

Some blows out the relief hole as a visual indicator. The rest goes out with the underwater exhaust. That keeps the exhaust housing from becoming hot hot.

 

[cbouch]

Please bear with me on this I am perinoid about this because I am afraid of overheating the motor. So, is it possible that no water comes out of the relief hole while the engine is at idle or fast idle???if it is possible then maybe I do not have a problem at all. What should the engine temp be at the head of all is working ok? I tried to send a picture but had no luck..thanks cliff

 

[todd281]

just a note .. you my want to check the new impeller . Make sure it is installed properly [vanes curved the proper way ] if its in wrong it will pump very little water.

 

[cbouch]

Think I figured out the photo thing

 

[cbouch]

Thanks I think it is installed correctly, shaft turns clockwise...impeller tails pointing counterclockwise..

 

[jimmbo]

Please bear with me on this I am perinoid about this because I am afraid of overheating the motor. So, is it possible that no water comes out of the relief hole while the engine is at idle or fast idle???if it is possible then maybe I do not have a problem at all. What should the engine temp be at the head of all is working ok? I tried to send a picture but had no luck..thanks cliff

Since there is no thermostat there should be water coming out of the exhaust relief shortly after the engine starts. As mentioned in earlier posts the water will look like a spray because of exhaust exiting. As the engine speeds up and moves forward, the water flow coming out of the relief will increase enough that it closes/seals the relief and all the exhaust exits via the exhaust snout behind the prop.
Little or no water coming out of there usually indicates the pump is working less than properly or the water line grommets are leaking, improper assembly of pump, worn pump housing/plate.

https://www.youtube.com/watch?v=eGWgeBXZuxo @1:44 shows what it should look like at idle

 

[oldboat1]

You don't have it deep enough in the test barrel, as mentioned.

 

[cbouch]

WATER WAS COMING OUT JUST WITH THE STARTER!!!! THANK YOU ALL!!
what I think happened was when I put the lower unit back on the water tube was not lined up..I fixed that and tested it in the barrel which did not have high enough level of water.

 

[cbouch]

THANKS EVERYONE, I NOW HAVE LOTS OF WATER PUMPING... NEEDED A BIGGER TANK LIKE THE LAKE...the problem was that I originally missed the water tube then corrected it but only tried to test in a tank that was not deep enough..

 

[F_R]

Heavy spray blown out the relief any time it is running is the norm. More like pouring out at high (planing) speed.

 

[racerone]

Very common for water level to be to low in test buckets.----Those pumps when worn even a little do not prime very well with water just covering intakes.