Water pump question

dleetch

Cadet
Joined
Jan 19, 2014
Messages
14
I have a 1978 Mercury 20HP, short shaft that runs great but when I am running it in a bucket and switch from fwd, N, rev the water stops spitting out for a few seconds. Is this normal?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
39,410
Re: Water pump question

Not normal.----The waterpump keeps pumping in gear or in nuetral.--Water must be at least 6" above the pump.--Often folks think that just the intake screen needs to be covered.
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: Water pump question

The problem with running in a bucket or barrel is the water becomes aerated. best to change impellar if you don't when it was last changed. piece of mind.
 

thebubba

Cadet
Joined
Dec 6, 2011
Messages
17
Re: Water pump question

I agree that you should change the impeller if it hasn't been done for certain in the last 2 years. You must have the water level up above the actual impeller which is located a few inches above the cavitation plate. Running in a small bucket is a bad idea, at least use a barrel or large trash can to test. Don't get to carried away with the throttle in a barrel. Also the water gets pretty dirty when you run it in a barrel for much time.
 

dleetch

Cadet
Joined
Jan 19, 2014
Messages
14
Re: Water pump question

How hard is it to change the impeller and what sort of cost am I looking at? I am trying to sell it and this caught the attention of a buyer. I want to make it right.
 

dleetch

Cadet
Joined
Jan 19, 2014
Messages
14
Re: Water pump question

Interesting info, thank you. Is it safe or safer to use a hose and muffs?
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: Water pump question

If you are selling it, you should replace the impeller and save yourself more trouble, if and when the buyer has questions or trouble with the motor. Giving the buyer copies of the sales receipts for all the parts that you put in the motor helps the sale of most all motors. When running motors in a barrel, the water should be at least 5" over the cavitation plate, and the motor should never be run over a fast idle as damage to the motor can be done. JMO
Oldman570
 
Last edited:

dleetch

Cadet
Joined
Jan 19, 2014
Messages
14
Re: Water pump question

If you are selling it, you should replace the impeller and save yourself more trouble, if and when the buyer has questions or trouble with the motor. Giving the buyer copies of the sales receipts for all the parts that you put in the motor helps the sale of most all motors. When running motors in a barrel, the water should be at least 5" over the cavitation plate, and the motor should never be run over a fast idle as damage to the motor can be done. JMO
Oldman570[/QUOTE. How hard is it to change the impeller on a scale from 1 to 10 for someone who has a pretty handle on mechanical stuff? Also is it bad to haul an outboard on its back laying down for about 30 minutes?
 

dleetch

Cadet
Joined
Jan 19, 2014
Messages
14
Re: Water pump question

Thanks for the info. How hard is it to change out the impeller? I have a decent understanding of mechanical operation but no experience with impellers. Also is it bad to haul this motor laying on its side for 30 minutes or so?
 

oldman570

Lieutenant Commander
Joined
Mar 25, 2011
Messages
1,615
Re: Water pump question

Changing the impeller is not that hard to do. You have to remove the LU and there is a bolt under the plate/tork tab above the prop besides the ones that can be seen. It is best done whit the motor in FWD gear when removing and replacing the LU on the midsection.
As long as you lay the motor down on the tiller side, and not the shifter side, you can haul the motor most anywhere. Placing a old blanket or something under the motor will help. JMO
Oldman570
 

Ant-Knee

Petty Officer 2nd Class
Joined
Oct 14, 2011
Messages
139
Re: Water pump question

I do my impeller once a year, Every summer..
Do it once and you'll be a pro... Very e-z to do...

Ant...
 
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