Evinrude 75hp 1965(?) Lower unit leak

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olegk

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May 22, 2010
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Hi guys,
My first post here and I just joined happy boating community.
Need your help!!!
Got boat and motor as a gift from friend.
About my motor. Wnt to mechanic shop today. Based on schematics model number is 75552R. No tags, nothing.
Motor runs, shifts gear really hard.
When I opened drain hole in lower unit, mix of water and oil came out.
Removed lower unit. Did pressure test. Bubbles going out of water intake hole (see image). No bubbles going from other places.
So. It seems to me the leak inside the water pump, because no bubbles from outside water pump unit. Am I right?
Kind of hesitate to open/remove water pump unit.. Anything I should be aware?
Here I am...
Where I can find seal kit for 1965 year model? I put more pictures if anyone can recognize the motor model.

Thank You!!


PIC_0147.jpg


PIC_0148.jpg


PIC_0142.jpg



PIC_0143.jpg
 
W

wilde1j

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Messages
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Re: Evinrude 75hp 1980 Lower unit leak

Re: Evinrude 75hp 1980 Lower unit leak

Well, I don't think it's a 1980 motor. I would guess somewhere around mid '60's. Look for a freeze plug on the aft top of block ... it should have model and serial. Also, port side of mtg bracket should have a data plate.

The leak is most likely a drive shaft seal.
 
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olegk

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May 22, 2010
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Re: Evinrude 75hp 1980 Lower unit leak

Re: Evinrude 75hp 1980 Lower unit leak

wilde1j said:
Well, I don't think it's a 1980 motor. I would guess somewhere around mid '60's. Look for a freeze plug on the aft top of block ... it should have model and serial. Also, port side of mtg bracket should have a data plate.

The leak is most likely a drive shaft seal.
Click to expand...

I don't know if it was freezing cup, but on cap on the top of power head right below timing belt
I found:
307757-P
Is it number? Too much light to see numbers on the picture
PIC_0140-1.jpg
 
W

wilde1j

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Re: Evinrude 75hp 1980(?) Lower unit leak

Re: Evinrude 75hp 1980(?) Lower unit leak

That doesn't look like a freeze plug and the number looks like an OMC part number.

here's an example of a core or freeze plug:
 

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olegk

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Re: Evinrude 75hp 1980(?) Lower unit leak

Re: Evinrude 75hp 1980(?) Lower unit leak

wilde1j said:
That doesn't look like a freeze plug and the number looks like an OMC part number.

here's an example of a core or freeze plug:
Click to expand...

Nothing... I found freeze polug on exhaust housing, but there nothing on it.
 
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olegk

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May 22, 2010
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Re: Evinrude 75hp 1980 Lower unit leak

Re: Evinrude 75hp 1980 Lower unit leak

wilde1j said:
Well, I don't think it's a 1980 motor. I would guess somewhere around mid '60's. Look for a freeze plug on the aft top of block ... it should have model and serial. Also, port side of mtg bracket should have a data plate.

The leak is most likely a drive shaft seal.
Click to expand...

Just came from a repair shop. it seems like it is 1965 (based on schematics I have seen) Model 75552R year 1965. Where I can find lower unit seal kit?
 
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wilde1j

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Re: Evinrude 75hp 1965(?) Lower unit leak

It would help if you had part numbers. sea-way.com has parts for old motors.

You can order a parts list here: outboardbooks.com
 
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olegk

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May 22, 2010
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Re: Evinrude 75hp 1965(?) Lower unit leak

Here it is!!
Drive shaft seal (underneath of water pump unit) doesn't look well. Am I right?

PIC_0144-1.jpg
 
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olegk

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Re: Evinrude 75hp 1965(?) Lower unit leak

wilde1j said:
Can't tell from looking at the outside, but that is likely where the bubbles were from. Water pump kit is separate. As long as it's apart, I would do a complete water pump kit.

See here for water pump guidance:
http://forums.iboats.com/showthread.php?t=309188
Click to expand...

Ahh.. I should run pressure test after I removed water pump but before
I removed the seal. pic below
PIC_0145-1.jpg


PIC_0146-1.jpg
 
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wilde1j

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Re: Evinrude 75hp 1965(?) Lower unit leak

Make sure to clean up the driveshaft before assembling. I would suggest a pressure test after you get the seal carrier tightened down. Way easier to do now and find a leak, than after the LU is back in place. Test should be done w/o gear oil in the LU.
 
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olegk

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wilde1j

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olegk

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Re: Evinrude 75hp 1965(?) Lower unit leak

wilde1j said:
The two seals with the metal carriers are most likely prop shaft seals, not drive shaft seals. Prop shafts are typically sealed with two seals, back to back w/ opposite orientation to seal against pressure and vacuum.

Did the seal you removed have a metal carrier?
Click to expand...
Yes it has. Didn't press out yet. Still in pressed-in in the plate.
Drive shaft diameter 0.75 inch seal metal carrier diameter1.35 inch
Almost the same for little smaller diameter shaft
http://www.iboats.com/Drive-Shaft-O...****.780459142--view_id.171761--viewcart.long

I starting having doubts about bubbles. There is a pressure release hole with nipple sitting in it (like little umbrella). See the plate picture above (for the hole). It seems the bubbles were coming from there. To confirm I need to put the plate back and run pressure test again to see if bubbles going to be from drive shaft seal as well
 
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olegk

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Re: Evinrude 75hp 1965(?) Lower unit leak

Did pressure test up to 15-20 PSI no bubbles. I did block the hole in drive shaft seal plate underneath of water pump(what the hell is this? See pic below: It has umbrella like part sitting in the hole with spring below it.) Have no idea what purpose if this part? Release pressure?
But nothing push it back to the hole..Something not right here. This is only place water can come in... Really tempting to seal it for good...It should not be water there, not much, because shaft going into tube and there is rubber ring on top of the water pump/shaft hole. against which the pipe pushes.
PIC_0144-1.jpg
 
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wilde1j

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Re: Evinrude 75hp 1965(?) Lower unit leak

Don't know either what that piece is, but I doubt it's for pressure relief.
 
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ltraci2

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Mar 2, 2010
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Re: Evinrude 75hp 1965(?) Lower unit leak

Thank you for using my site to find your parts. I do not have very much available on the site yet, so feel free to drop me an email with any requests.

While the motor person is gone due to military reasons, I will do my best to find needed parts. Given a part number, I can usually find anything! I also have access to many NLA parts.


Best of luck in your boat repairs!
Traci
http://www.buyboatmotorparts.com
 
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R.Johnson

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Sep 24, 2003
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4,446
Re: Evinrude 75hp 1965(?) Lower unit leak

That driveshaft seal housing does have a pressure relief. The upper and lower housing does not look like it is mated together properly, or is that a ring of sealant I'm seeing? The soft plug on the block is missing as shown in the powerhead photo with the magneto. That gearcase back then only used single seal's.
 
F

F_R

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Jul 7, 2006
Messages
28,226
Re: Evinrude 75hp 1965(?) Lower unit leak

That is a 1960 motor, only year with the two-piece drive shaft with a coupling above the water pump. That IS a pressure relief valve. I seal it permanently. A dab of JB weld will do it.
 
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