Mercury outboard not peeing.

[cheetahgod]

I have a 1980 7.5hp merc serial number in the 57000s. Got the motor running but it’s not peeing only air coming out. Checked the impeller and it seems to be in good condition. Blew into the pipe that connects to pee hole and can feel air coming out of pipe in the lower unit. I Check the thermostat and found there’s no thermostat. What else could prevent water from coming out?

[cheetahgod]

I connected a garden hose to the top pipe and water came out the lower unit. Could I be missing some seals on the lower unit ?

[billw]

Those engines have an engineered bend in the water tube. Careless installation of the lower unit can sometimes cause this bend to go too far, which essentially makes the tube too short to go into the grommet on the top of the pump. Before doing anything else, I would take some careful measurements to make sure this is not the problem. Measure the fore and aft position of where the bottom of the water tube should be in the drive shaft housing, with relation to the pump. Then, compare height/depth measurements of the grommet location in the pump, with the end of the water tube. The tube should go fully into the grommet. If this is a problem, the tube can be carefully straightened out a bit, using a long crow bar or similar tool.

If this happens to check out good, then you can find a piece of copper tubing to simulate the height of the actual water tube, put it into the pump, stick the lower unit in a barrel of water and turn the drive shaft with a drill motor, to check the pump operation. Please take care not to electrocute yourself, of course. Battery drills are best…..

Long live American manufacturing!

[westwind]

The impeller may be the problem, even though it looks OK. The tips of the vanes must contact the outer edge all the way around. If the tip separates from the pump wall, even just a tiny bit, it will not pump properly. As the little chamber gets smaller to force the water up the tube, enough slips through the gap into the next chamber that it doesn’t build any pressure.

[jpatti75]

One other thing to check that has occurred to me on both my Merc 60 and Merc 200. Those little pee holes can become blocked pretty easily with just a little bit of sediment, which can collect in the cooling passages. Take a pipe cleaner or even a piece of wire and see if you can dislodge anything in the pee hole. I was running my Merc 60 last spring and noticed that it had stopped peeing. I initially panicked, but ended up cleaning out the pee hole with a fishing hook … it was pumping fine, but the smallest bit of sediment blocked the hole.

JP

[troy]

Remove the propeller, behind it you should find a plastic thrust washer, that will probably be broken,these motors take in water around the prop also, yea I did not believe it would be the problem either, till I removed the prop and broken thrust washer and started the motor it was peeing like a 13hr old again. they do not sell them anymore, the motor I worked on had same situation, you had, I ended up making one from aluminum. problem was solved 😀

[Author]

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