Changing Waterpump on 20hp

[baconbiscut]

just recently I bought a 20 HP Mercury off of ebay year 1963-1965 i'm not really sure yet. Anyway i heard that these engines are tricky to work on as far as replacing replacing the waterpump goes. what do I have to do to replace the waterpump on this engine

Thanks, Dan

 

[Laddies]

Re: Changing Waterpump on 20hp

If it's a merc 200 your alright if it's a mark 28 your in trouble, a manual is a good place to start with either engine.

 

[tashasdaddy]

Re: Changing Waterpump on 20hp

becareful, some of those older mercs were known to have right and left hand threads on some bolts. less determine what you have, before we worry.

 

[Motor Boater Bill]

Re: Changing Waterpump on 20hp

If you post your serial number we can give more specific help--I love the 20's!

 

[baconbiscut]

Re: Changing Waterpump on 20hp

Well i finally got the motor. When i got home i put it in a bucket of water and tryed to start it up. Well we got it started alright the thing reved way up scaring the crap out of me and my friend and then it jumped into gear and made a huge wall of water. I was able to shut it off but it left us with our knees shakin. Anyways where can i find ther model and serial on this engine i can't seem to find it. I still think it's a 63-65 howeve i would also like to know the correct way to start up one of these things without blowing a rod.

Thanks, Dan

 

[Motor Boater Bill]

Re: Changing Waterpump on 20hp

You need to be ready to back off the throttle when it fires, they will take off. Look for the serial number on a plate that will be either on the side of the leg or in between the transom clamp screws--more likely the latter. Keep in mind that the choke can also serve to shut down a motor (usually) if the kill switch fails. I've experienced the jumping in to gear thing, it can be from the linkage being maladjusted or from the cam in the lower unit being worn. Watch out for that! I named my first Merc 200 "The Monster" given the contrast to my Merc 110.

 

[baconbiscut]

Re: Changing Waterpump on 20hp

I went to old mercs website and looked up my serial # which makes my motor a 1963 so it has been repainted black. I found all the parts I need i just need to fugure out how to get the lower unit off. There is a bolt located near where the shift cable connects to the lower unit. but surely there are more bolts holding this thing on. Any help would be greatly appreciated I really don't have a large budget being only 14 years old so I can't pay 75 $ for a service and then by all the parts. So any help here will be greatly valued I really wabt to get back on the water and go fishin!
Thanks, Dan

 

[baconbiscut]

Re: Changing Waterpump on 20hp

I still need to get that lower unit off ant advice.
Thanks, Dan

 

[Laddies]

Re: Changing Waterpump on 20hp

Dan, where is the shift handle on your engine front or side

 

[baconbiscut]

Re: Changing Waterpump on 20hp

On the side opposite of tiller handle.

 

[Laddies]

Re: Changing Waterpump on 20hp

Hope this is what you need

 

[baconbiscut]

Re: Changing Waterpump on 20hp

Thanks so much. here is a pick to off the motor if i can get this to work.

 

[baconbiscut]

Re: Changing Waterpump on 20hp

Are these where the bolts are that attach the lower unit to the rest of the engine the direction weren't quite cleear or i didn't understand.

 

[Laddies]

Re: Changing Waterpump on 20hp

Yes