1987 Mercury outboard water pump

[Micropertus]

Just bought this boat that hasn't run in 2 years. Didn't have a problem getting it started but after maybe 10 seconds didn't have any water flow out the flow hole. Is there a thermostat that might be holding the water back or should I just change the pump?

 

[GA_Boater]

Welcome aboard.

Ya gotta tell us which 1987 Merc you have.

After 2 years of sitting and no history, changing the impeller is a good idea,

 

[Micropertus]

Does Black Max help with the type of Merc? If not, dare I ask where do I find what you're looking for? This is new territory for me and quite the learning experience!

 

[Chris1956]

Year and HP is what is necessary to help you. You gave us the year, so just HP is necessary. V6 engine?

 

[444]

Buy a water pump kit and change it. Not tough to do on these mercs. The tell tale should pee whether the thermostat is open or not. You can always try blowing some compressed air through it to make sure it's not plugged. Are you running it in a barrel or on the ear muffs? If on the ear muffs, you should be getting water exhausting out the prop hub and after idling the engine for a while, the water should feel slightly warm.

Also worth noting, my late 70's black max 175 only ever dribbled and spit water while running on the ear muffs, but had a decent stream when in the water where my mid 80's 90hp inline 6 always pissed like a race horse.

 

[Micropertus]

Thanks again and I can't believe I didn't put down 200hp!
I was using the muffs and didn't notice any water coming from the prop hub.
I will change out the water pump and check for any blockage!
Thanks again for your patience with a green horn!

 

[Chris1956]

A lot of those V6 Mercs do not have a telltale stream, until the thermostat opens. On a flusher, the thermostat may not open.

Look for water exiting the prop hub and any gratings above the antiventilation plate. If you see water exiting the motor, the water pump is working.

 

[Micropertus]

When I had the muffs on, I had the garden hose wide open for probably 20 minutes. That being said, when I went to put new oil in the lower unit, I got about a half a cup of left over oil from last year's winterizing along with about a cup of water! No milky mix! Is it possible the garden hose pressure pushed the water past a seal? Should I get them replaced right away or maybe run it for a couple hours and change the oil to see what it looks like?

 

[flyingscott]

Pretty sure if you ran it for 20 minutes and it didn't overheat pump is working. No the lower unit is separate and my guess is the water has been in there for a while because it had time to seperate from the lube.