1972 mercury 50hp doesnt pump water?

[gameaholic]

New to me boat motor isnt pumping water, we pulled the foot and checked the water pump it looks fine. Does this engine have a thermostat if so where is it. weep hole was clogged so we pulled the hose to it and dont get water out the hose or the two rectangular ports on the back of the motor.

 

[davebad22]

Re: 1972 mercury 50hp doesnt pump water?

do you have the serial number?

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

334 8971

 

[davebad22]

Re: 1972 mercury 50hp doesnt pump water?

not sure but I don't think there is a thermostat.
Couldn't find anything in the lines of a parts list for that serial #

here some links that may be of interest.

http://www.outboardrepairs.com/topics/015792.html

http://www.outboardrepairs.com/topics/000695.html

 

[JUSTINTIME]

Re: 1972 mercury 50hp doesnt pump water?

there is a check valve on it

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

where is the check valve? Is it at the other end of the pee hose [it goes under the port side rear corner of the powerhead] I can blow backwards through the hose and hear air coming out the lower foot area. Also someone said some mercurys dont like ear muffs to submerge in water, is this true?

 

[JUSTINTIME]

Re: 1972 mercury 50hp doesnt pump water?

do not know what side but usually starboard side of boats are most pee holes

i have the part look up program for all of mercury products and force, i did not see a t stat but i could be wrong

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

pee hole is on starburd side but hose from pee hole goes to under port side to a fitting under the shift linkage

 

[trigger-trainer]

Re: 1972 mercury 50hp doesnt pump water?

I've seen the rubber gromments on the top of the water tube(right next to powerhead) shrink and close off the water passage to the powerhead.
I'd try and run up a little piece of wire up the p-hole and if that doesn't cure it check out the grommet at top of water tube. You have to pull the powerhead to get to it.

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

can I pull the foot and run a wire up the tube to see if it hits something soft? Never pulled a powerhead. Is it very difficult? Or should I let a shop due that

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

ok stuck in tank of water still no water up top, but with ears ithas water coming out the prop. Pulled the foot stuck a water hose to the tube and had water come down exhaust shaft, pee hole, and inside case...ie outside area around exhaust shaft. Noticed area around water pump was oily so pulled drain from foot. Foot has oily water in it. Does this mean cracked foot,or bad seal on shaft? And would this contribute to not getting water to the top of the engine. Thanks for help.

 

[Silvertip]

Re: 1972 mercury 50hp doesnt pump water?

It more than likely means you have two problems. The lower unit needs to be resealed. Drive shaft, shift shaft, housing and propeller shaft. Those seals keep water out and oil in. They have nothing to do with the engine not getting cooling water. You said you pulled the foot and the water pump impeller looked good. When you go that far it is really silly not to replace the entire pump assembly, especially since this is a new to you motor. At least you know that part of the system is functioning. Are you sure the key is in the shaft and that the shaft isn't just spinning inside the impeller hub? As was mentioned, the grommets on the water tubes may be gone or the things are misaligned when you put it together. Also, running on a hose & muffs you are "forcing" water up the system so even a very weak or damaged impeller may flow water. That's not a very meaningful test.

 

[gameaholic]

Re: 1972 mercury 50hp doesnt pump water?

Key is in shaft. Dont know if it is spinning on shaft or not.I ordered a new pump kit with housing, but cant get the lower water pump housing to come out. Any tricks to it?

 

[tmcalavy]

Re: 1972 mercury 50hp doesnt pump water?

No thermostat on that Merc...I had a identical 73 model. It should pee out the hose a little at idle and stream will increase as rpms go up, at least that's what mine did. I would replace the entire water pump. I had the lower unit on mine resealed and driveshaft built up (it was badly pitted) and turned back down for about $125 by our local Merc guy. Check the water tubes that carry h2o from the pump to the water jackets. Might also be an obstruction in the water jacket passages...go easy on those bolts, they can twist off on a motor of that age. Water jackets should be cool to the touch when it's running on muffs or in the lake. If you can hold your hand there when it's running, the prob is between the powerhead and the pee hole. Good luck, great outboards those Merc 500's.

 

[stoabcrem]

Re: 1972 mercury 50hp doesnt pump water?

no thermostat equals water coming down exhaust housing and outside of exhaust !!