1979 Mercury 200 20hp - water pump issues

[campnfish]

Took this beast out of the shed and fired it up yesterday, but I'm not getting any water through the pee-hole! Here are the details:

Last used summer of 2012 after a water pump and carb replacement. Functioned well, no issues.
Stored in my shed since then (2 years)
I did not do any sort of prep or maintenance before I put it away.

So after the requisite dozen or so pulls, it fired up and idled ok. I did not see any water come out of the tell-tale, but I could feel air coming out. Had it running for 30 seconds or so but I didn't want to damage my engine so I turned it off. I had it sitting in a garbage can full of water - made sure the water level completely covered the lower unit, about 2 inches or so over the unit.

I really wanted to avoid having to drop the lower unit and fiddle around in there - it is a HUGE hassle to get it back on because the copper pipe the water is pumped up has to be lined up just right, while ensuring the drive shaft is also lined up.

I've heard that the engine has to warm up before the thermostat opens to allow water to flow, then also heard that no, it should start pumping right away. I'm used to OMC engines where the water comes out of the tell-tale as soon as you fire them up, expected the same from the Merc. I was hesitant to run it to find out of the thermostat would open because I know it could damage the engine.

Any advice would be appreciated.

Cheers,

Campnfish

[smitty55]

Could be spider webs have plugged the water intake. You could try poking some wire up the chute and maybe some air pressure too. It should pump water right off the bat. You definitely don't want to run it with no water flow. Good luck with it.

Cheers

[SeaMonster]

You should be getting water out the pee hole. Sometime if the old impelled that was changed was busted up some pieces can clog the line. If you have a compressor you can blow air back through the pee hole to free any clog.
However taking off the lower unit should be done before that. Bah dropping a LU isn't that bad.

[campnfish]

Thanks for the pointers guys. I've got an air compressor so I'll try blowing out the tube and see what happens. Might as well drop the LU and do it right. Oh the pleasures of keeping older outboards running....

[campnfish]

Update: So I ended up dropping the lower unit. Turns out the black rubber grommet / spacer that fits over the end of the copper water pipe, then into the water pump housing, had moved up the water pipe so there was not a firm seal at the base of the pump. Reseated the grommet and the pipe after MUCH hassle, have yet to fire it up and test it.

The reason I really didn't want to drop the LU was because getting the driveshaft AND the water pipe to go in their respective holes in the engine block is damn near impossible. You have to have the steadiness and patience of a monk to get it to line up just right. Ended up using a Froster straw (the big straws from Mac's) as a guide to line it up.

Going to fire it up when I get home today and hope to bloody hell it pees water. If not I might have a '79 Merc 20hp for sale, some lower unit work needed .

CampnFish