Mercury 500 water pump

[Uxboat]

I have a 1977 Mercury 500 {50 Hp} which I just replaced the the water pump in,however I have no flow at pee line. Want to double check with some one who has done this before,

one the shifter should be in forward before dropping lower unit right ?

two to get the water pipe back in the pump correct must the motor be vertical ?

Standing behind the motor the pee line is the black plastic hose on the right sticking out about a inch right ?

If I pull down on the steel tube that goes into the water pump to check it,will it go back up alright ? Should a person stick the tube in the pump housing first then lift the lower unit up ?

Sorry for all the questions the more posts and info I saw the harder the job became.
Thanks Mike

 

[1970Thunderbird]

Re: Mercury 500 water pump

I have a Mercury 800 of the same year. I think they're really close.

1. Not sure. I thought I had mine in neutral, but forward does sound correct. If this isn't answered by tomorrow, I'll take a look at my manual when I get to work.

2. I reinstalled mine with the motor tilted up on the rests. Found it fairly easy to realign the water pump tube to the copper one going into the block.

3. You are correct about the pee port being that little black hose.

4. Try to avoid pulling out that tube. It will go back in place, but it can be a bit of a bear getting light into the lower leg to find the right place to put the tube. Right next to it is where the drive shaft goes into the block. The water tube is right next to the exhaust shaft.

 

[Uxboat]

Re: Mercury 500 water pump

If I had put it together with the pipe out of the water pump,and then tighten the bolts does the pipe bend or does it fit at top in rubber and just need to be pulled a little down ?

Twice I have run the engine waiting for water and am worried about wrecking it,ran into the same problem as the other fellow with the messed up gears.As I remember the little rubber ramp was lifting the pin in leg up for neutral.

 

[mike1245]

Re: Mercury 500 water pump

ok put motor in foward gear
then tilt engine
then remove bolts and drop lower unit
remove water pump cover and water pump
put on new pump ensureing key way is set and pump turns with shaft
next put a little oil/wd40/vassoline on pump NOT A LOT THOUGH
then with cover on top of pump turn shaft counter clockwise as looking down from top of waterpump
as u turn shaft ccw slightly push down waterpump houseing and install nuts
as u put lower unit om u might have to turn prop to line shaft back upthen slightly push up ion lower unit ensuring all tubes and shifter cable line up sometimes it helps to have another person slightly move the shifter a little as you push up on lower unit should go on with little effort and also make sure splines are clean where it goes into the flywheel

hope that helps also with lower unit off blow some commpressed air into the pee hole to make sure its clear

 

[Uxboat]

Re: Mercury 500 water pump

Thanks guys this weekend I will start fresh and drop the lower end,if the tube did not go in the pump then I am concerned,what happened when I bolted the lower unit up. Does it bend the tube or push it into the motor and maybe do damage up there.

Been alot of posts lately on water pump replacement problems and or the shift problems that can go with it,maybe the best advice is take the engine into the dealer.

Cheers and Thanks Mike

 

[1970Thunderbird]

Re: Mercury 500 water pump

If the metal water tube going to the block doesn't go into the water pump, it'll probably just sit somewhere nearby. I don't think it would get forced into the block. Rather, I think the tube would just shift to the side a bit.

Actually, a lower unit removal and reinstallation isn't that difficult. Not saying don't take it to a mechanic, but I enjoy learning the intricacies of the motor and how it works.

Good luck!

 

[turtles11756]

Re: Mercury 500 water pump

the shifter at the top side of the motor must be in the same gear as the lower unit when brought back together or you won't be able to shift thru gears right when your done. if you fool with the shift shafts when disassembled that's when the problems start for some new to this. try installing water tube greased at the upper end first then bring up the lower unit and you might be able to see the water tube go in correctly at the water pump end. grease the splines on drive shaft (no grease at the very upper part) and shift shaft, make sure the key way is in on the (greased) impeller and you should see water this time at the tell tale hole. when your done get familiar with the shift cable at the motor and notice where all the gear positions are .the prop will spin freely in either direction when in nuetral

 

[Uxboat]

Re: Mercury 500 water pump

Thanks gentlemen that,s why this forum is the best !

 

[64osby]

Re: Mercury 500 water pump

I have a 1967 Merc 500 and have had the lower end off a couple times. The way I have aligned the tube is by supporting the lower end with my knee or leg once it is close but not touching, and using a long (10" + handle) thin bladed screw driver and a flash light. I get it close and move the tube to align, then slide the lower end up with my leg. It's worked every time, and I always get a nice bruise on my leg. Have fun

 

[Uxboat]

Re: Mercury 500 water pump

Yeah, I guy I work with told me today he use,s a tool made from a coat hanger a straight length then a 180 bend to hook and hold the tube to guide it in.

 

[64osby]

Re: Mercury 500 water pump

The Coat hanger sounds pretty good, I might have to try that next time.

It's still a 3 handed task and I don't think my tube would ever hit the mark with out putting a little pressure on it.