Old Merc Outboard Question
I have 2 50Hp Jets Mercury. One is 1970 and the other is 1975. They had been sitting for 10 years. I have managed to get them running (unbelievably strong too) However I dont have any water coming out the little pee hole. I was told by a friend that the water actually comes up into the motor and then back out through the exhaust/jet and tha tthe pee hole was just a "sight check" and not a necessity. He said that the motors are liely getting water and that the tubes to the pee holes are plugged or craked from old age
I did replace the impellers on both motors today and they were toast.. but brnad new now.. but still no water through the hole..
I haven't heard that before...But on the other hand doesn't mean he's wrong either.
When I rebuilt my old merc. I went to the library and borrowed there mercury books there. They have a whole line of chiltons type books for older mercs. Go and check a few out and take a look for the right information.
I would hate to see you possibly ruin a motor.. Better safe than sorry and I'm sure you will learn alot more about your motor too. I did that's for sure.
Personally, I like seeing water out of the pee hole on my motor, It's a "Yep, things are running right." kinda' thing.
Those "pee" holes are IMPORTANT as they indicate that the water pump impeller is working correctly. Especially with older motors which do not have temp alarms, how will you know your motor is running as it should? Wait till a gasket or powerhead blows? Bad advice.
1. get a piece of electrical wire about 10" long (fairly stiff copper wire used for wiring houses, can cannabalize a piece of Romex) and file/sand the ends smooth, carefully insert the wire up into the "pee" hole and gently push it/fish it around until you cannot insert it any further; do this while motor running (in the water or motor flusher attached and water getting into the lower intackes. Another thing that works well is a piece of 200 lb or so mono leader material, it's stiff enough to go thru any blockage.
2. You should now see water coming out, if not, DO NOT RUN MOTOR ANY LONGER UNTIL PROBLEM SOLVED.
3. You can also follow the rubber hoses leading to the "pee" outlet and disconnect them as far as you can, could be blockage in there farther than the wire/mono can reach.
Were your water pump impellers intact? I had a 72 Merc, and I had little chunks up in the tube. I had to get thin needle nose pliers and pull them out. On a smaller merc we kept a twist tie to poke in the pee hole. Some reason it would plug up.
The impellers were bad and I replaced them.
I have one motor peeing properly. THe other motor is not. I can get it to pee if I rev up the motor, but as soon as I brring it back to idel it stops peeing and the motor gets hot.
My first thought is that perhaps there is a gasket or something that is not sealed correctly on the water pump reventing good flow at idle.
My next thought is to crack the water jacket open on the power head to see if there is debri that got sucked up.. any thougts are appreciated!!!!
It could possibly be the powerhead gasket, or headgasket. When idling the impeller cant push enough water through to offset the pressure from exhaust to get to the motor, when you rev it up, impeller pushes harder, or could be the water tube from the water pump to the powerhead, good possibility if it was run in salt, or the sacrificial anode was painted. might have a hole in it
Had a friend did this, New impellor pumped at a higher Rpm , not at Idle, Didn,t get the pickup tube lined in the hole, when slapped it together, Over Hr, to get him to take it back apart, 10 min . to fix, Worth a look?
Last edited by SusitnaAk; 09-03-2008 at 22:18.
Had this happen w/ my Honda 90
When I started it on the hose this spring, it wouldn't pee. Just out of curiosity I pulled the plastic thingy on the cowling away from the rubber pee hose and it put out water just fine when I started it again. I stuck a wire up the plastic fitting and a dead spider came out! Check for obstructions before you do anything radical.
Originally Posted by Kenai Boater