1984 75hp mecury wont pump water

M

mcgrawver

Cadet
Joined
Apr 10, 2012
Messages
7
Motor sat for 8 years without being started. I replaced the water pump impellar but it still wont pump water. Is there a thermostat that could be not working? I know this may be a dumb question but Im new to working on outboards. Any feedback would be helpful, Thanks
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: 1984 75hp mecury wont pump water

Are you SURE the impeller key stayed in place as you slid the impeller down onto it?

And that the water transfer tube slid into place in the water pump as you raised the lower unit back up?
 
M

mcgrawver

Cadet
Joined
Apr 10, 2012
Messages
7
Re: 1984 75hp mecury wont pump water

I removed the lower unit today to double check, and the impellar key was where it should be and it appeared that the transfer tube had been connected because the plastic fiitting from the end of the copper pipe pulled off and was still in the impeller housing. It seems like its trying to pump because when i start it, water comes out of vents directly above the lower unit, but not out of the pee hole. Its almostlike the transfer tube could be clogged or something, but im not sure what to do about it. Thanks for your reply and help
 
BonairII

BonairII

Commander
Joined
Jun 7, 2011
Messages
2,727
Re: 1984 75hp mecury wont pump water

Did you have water flow just before you replaced the impeller? If so, you prob assembled something incorrectly. Check to make sure impeller vanes are going the correct way.

if you didn't have water flow before the impeller was changed then you need to run water into the plumbing in the leg and see if you have a blockage.

To test the t-stat, pull it and put it in hot water...should start to open at 140 degrees(or whatever temp your t-stat is rated for)
 
M

mcgrawver

Cadet
Joined
Apr 10, 2012
Messages
7
Re: 1984 75hp mecury wont pump water

It wasnt pumping when i first got it started, so i changed the impeller. Im almost positive I have everything installed correctly. Today I will put a hose to the transfer tube to see if it is clogged, thanks for the idea. Where is the thermostat located on the outboard? I cant find it on any diagrams or online parts searches
 
M

mercuk

Petty Officer 2nd Class
Joined
Feb 6, 2012
Messages
122
Re: 1984 75hp mecury wont pump water

mcgrawver said:
It wasnt pumping when i first got it started, so i changed the impeller. Im almost positive I have everything installed correctly. Today I will put a hose to the transfer tube to see if it is clogged, thanks for the idea. Where is the thermostat located on the outboard? I cant find it on any diagrams or online parts searches
Click to expand...


You wont find a thermostat because there isn't one......
Trust me I have EXACTLY the same engine and rebuilt the whole thing and I know it inside out....:D
What you want to do is pull the lowe unit off, and connect your hose pipe straight to the copper tube inside the leg. Turn on tap. If water comes out the pee hole, you have done something wrong with your impeller replacement. If NO water comes out then you have a bloackage somewhere that needs freeing up.
Feel free to ask me any more Q's, I know this engine very, very well....:D
 
A

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: 1984 75hp mecury wont pump water

Have you tried sticking wire up pee hole while motor running.They clog up all the time.
 
T

Treker57

Petty Officer 2nd Class
Joined
Aug 23, 2009
Messages
136
Re: 1984 75hp mecury wont pump water

Mud dauber got the pee hole
 
M

mcgrawver

Cadet
Joined
Apr 10, 2012
Messages
7
Re: 1984 75hp mecury wont pump water

mercuk said:
You wont find a thermostat because there isn't one......
Trust me I have EXACTLY the same engine and rebuilt the whole thing and I know it inside out....:D
What you want to do is pull the lowe unit off, and connect your hose pipe straight to the copper tube inside the leg. Turn on tap. If water comes out the pee hole, you have done something wrong with your impeller replacement. If NO water comes out then you have a bloackage somewhere that needs freeing up.
Feel free to ask me any more Q's, I know this engine very, very well....:D
Click to expand...

Ok, thanks. I was beginning to think that there wasnt one. Im going to hook a hose up to it today and see what happens.
 
Wingedwheel

Wingedwheel

Lieutenant Junior Grade
Joined
Jun 16, 2009
Messages
1,071
Re: 1984 75hp mecury wont pump water

Something else to consider. if you only replaced the impeller and didn't install the whole kit, your rub plate could be worn and not giving you the proper seal inside the housing. I've only seen it happen a few times but it can happen. I do concur that the first thing to check should be whether the pick-up tube is plugged.
 
M

mcgrawver

Cadet
Joined
Apr 10, 2012
Messages
7
Re: 1984 75hp mecury wont pump water

Fixed! You guys were right, pee hole clogged. It was clogged above an elbow and i couldnt reach it with a wire. Took the back off and got to the hose. Pumps like a champ. Thanks for all the help. You guys told me more in a couple posts than my parts dealer could. Guess they just wanted the $75 a hour for labor! But thanks again, Im sure ill have more questions before Im done restoring this old boat...
 
T

Treker57

Petty Officer 2nd Class
Joined
Aug 23, 2009
Messages
136
Re: 1984 75hp mecury wont pump water

Glad it was an easy fix, makes you feel good.
 
You must log in or register to reply here.
Top