Merc 500 No Forward and No Pee

[mrkris]

I've got a 1977 Mercury 500 - 50 HP. Just bought it this year and I took it out for the first time. It starts great! Idles great! Goes into reverse and works great that way too

Here's where things start to go wrong.

1. it does not spit water. I'm thinking the water pump is bad. How much effort is it to repair the water pump? How much should a dealer charge to replace this? Is this something I can tackle in my garage? Where is a good place to find replacement parts?

2. when I try to put the motor in gear to go forward -it does not rev up. the rpms stay low and it putters along. Its almost like there is something wrong with the linkage or the carb. Again, the darn thing starts and idles great. Rev's up high in reverse -just not in forward.

Never the less, if you have any ideas as to what I can do to troubleshoot or resolve these issues -please let me know.

 

[jimdd810]

Re: Merc 500 No Forward and No Pee

First welcome and congrats.
Second get your self a good service manual for your motor.
Third with a good manual and some mechanical apptitude neither of your problems are to difficult. You have to remove the lower unit to service the water pump.

As for your problem with the throttle check all of the linkages. Have some one move the throttle forward while you watch the linkages. If every thing seems to be ok there then it could be a broken cable.

 

[Wingedwheel]

Re: Merc 500 No Forward and No Pee

If it revs fine in reverse, I'd suspect a problem in the control box. Perhaps the cam that moves the cable is broken or slipping in the forward range. Check and see if it moves the cable on the shift block mounted on the motor. If not then take the cover off the shift box and see whats happening inside when you push the lever forward.

 

[mrkris]

Re: Merc 500 No Forward and No Pee

Figured out the pee issue. plugged line. after a little cleaning it works like a charm.

 

[Wingedwheel]

Re: Merc 500 No Forward and No Pee

How about the forward issue?

 

[mrkris]

Re: Merc 500 No Forward and No Pee

I'll work on that next. at least now I'm not worried about overheating it. btw I pulled the lower unit and the impeller looks great -no issues there.

 

[mrkris]

Re: Merc 500 No Forward and No Pee

Ok, something to note to those curious few who drop the lower unit -pay very close attention to the shift linkage...

The linkage was not aligned properly. After some adjustment and a little help from the wife -its all back together and it shifts pretty nice. Tomorrow, I'm taking the kids fishing.

 

[latin monkey]

Re: Merc 500 No Forward and No Pee

yeah those dirt dawbers seem to love old mercs as much as we do