650 (1963) Water Pump Questions

1960 Starflite

1960 Starflite

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Since I've figured out my idle problem, thought it was time for a new water pump/impeller, since it hasn't been changed for several years.

The thing has a OEM pump housing (I think) made of aluminium and has a seal in the upper half. The new pump housing doesn't have the seal. (see photos). Also, the guide tube is melted at the upper part of it.

Questions:
(1) Do I have the wrong pump housing or is the upper seal no longer used?

(2) Should there be a gasket or deflector to protect the water guide tube from the exhaust?

Thanks
 

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Texasmark

Texasmark

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Re: 650 (1963) Water Pump Questions

No on the deflector/shield sort of thing...exhaust water and gasses go out that hole and you don't want to block them and apparently the water pump is cooled from within (fresh intake water) so you don't have to worry about exhaust elements flowing over it.

On the seal, you have to have the pump sealed so that you can pump water up to the powerhead. I realize that the impeller has a sealing ring on both sides , but for years, there was always another seal.

So, if the new one has no seal per se, is the seal actually the top of the housing. Slide it down over the drive shaft and see if it's a tight fit. May be and may be an improvement over the older rubber seal design. It's obvious to me that the top of the new one is different than the old one and the diameter of the holes seems to be about the same so it may be a better mouse trap.

I just pulled my service manual which covers 90-125 hp engines from '97 on and looked at the pump assembly parts breakdown. There are rubber seals below the pump which seal off the lower unit oil encircling the drive shaft, but once you come up from the ss plate that forms the bottom of the pump, that the impeller rides on, the only other parts are a gasket that fits on that plate and seals to the bottom of the cover, the impeller, impeller locking shim, cover, mounting screws and the exit tube (cover and exit tube one assy in your pic)....no separate seal. Soooo I guess the cover is designed to do the sealing too.

HTH,

Mark
 
1960 Starflite

1960 Starflite

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Messages
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Re: 650 (1963) Water Pump Questions

Mark, thanks for the fast feed-back. The new guide tube isn't part of the cover. I just stuck it in there for the pic. It (new cover) does have the rubber seal inside which seals the copper tube to the powerhead.

Your correct that the lower pump body does seal the bearing/lower unit. This is the old set-up that requires shiming the bearing for preload of the input shaft. It doesn't have a preload pin on top of the shaft.

I'll check out the clearence between the new pump cover and input shaft when I get out to the garage later today.

Thanks, Tom
 
merc850

merc850

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Messages
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Re: 650 (1963) Water Pump Questions

In picture 2 it looks like the exhaust tube in the driveshaft housing goes into the LU where your arrow is, if so there is a plate and gasket that goes in there to seal the exhaust tube. Part 39-40.
Lower-Unitsdriveshaft.jpg
 
1960 Starflite

1960 Starflite

Petty Officer 1st Class
Joined
Jun 23, 2011
Messages
380
Re: 650 (1963) Water Pump Questions

Mark
if the new one has no seal per se, is the seal actually the top of the housing. Slide it down over the drive shaft and see if it's a tight fit. May be and may be an improvement over the older rubber seal design. It's obvious to me that the top of the new one is different than the old one and the diameter of the holes seems to be about the same so it may be a better mouse trap.
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Well, that is just not the case. I measured the shaft OD is .873" and the top of the pump cover ID is .910" that would be .037" clearence, waaaaaay too much! I used the old pump cover, as the stainless body looked good and the seal did have some resistance yet.

merc850,
Thanks for the pic. Thought there should be something there. Now just where would I find a 48 year old part ???????? Yea, right.

Tom
 
merc850

merc850

Commander
Joined
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Messages
2,046
Re: 650 (1963) Water Pump Questions

Try a Mercury dealer,ebay or this site.
 
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