Cant Keep Water Out Of My Lower Unit!

[thejeep007]

OK IVE CHANGED THE WATER PUMP BASE ON MY 1970 650 4CYL 2-STROKE AND STILL GETTING MILK AFTER EVERY RUN... THE BEARING CARRIER O-RING WAS ALSO REPLACED, WHAT ELSE COULD IT BE THE ONLY THING I CAN THINK OG IS A SHIFT SHAFT SEAL, MY SELCO GREW LEGS AND RAN AWAY ANY ONE HAVE ANY THOUGHTS ON IF I AM GOING THE CORRECT PATH AND ANY QUICK RUNDOWN OF CHANGING THE SHIFT SHAFT SEAL AFTER LOWER UNIT OUT. THANK YOU:confused

 

[Laddies]

Re: Cant Keep Water Out Of My Lower Unit!

Pressure test the unit or use care and replace all the seals.

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

ran a smoke test and passes up to .02 in hg no smoke leaving, i wouid love to change all the seals at once but finding parts for a 1970 is a pain, flipped on an old timer looking for a flush plug when he told me "that motor is good for one thing, an ancor" his wrinkled @$$ is still around and so is my motor! i guess more testing or find lower unit for cheap, my understanding is they are pretty similar from 68 to 74

 

[Laddies]

Re: Cant Keep Water Out Of My Lower Unit!

Take your serial number and go to NAPA, have the part guy open the marine catalog to the back of the seal section the numbers are listed there by the serial number.

 

[Moody Blue]

Re: Cant Keep Water Out Of My Lower Unit!

I chased a similar problem a couple years ago. Did end up being the shift shaft bushing seal, the last thing I changed.

A simple and inexpensive repair. Just picked up a new bushing and seal ($20) and will be replacing the one in my 1970 800 which is also slowly gaining water.

The manual tells you you need a special tool to remove the bushing. I made one myself in about 5 minutes out of a piece of sch40 pipe I had lying around. The tool is nothing more than a tube with two protruding tabs that engage two slots in the top of the shift shaft bushing. Clamped the vise-grips onto the pipe and out comes the bushing.

As an aside, I assume you have already put in new sealing washers for the drain and vent plugs? First thing to do if not.

 

[emckelvy]

Re: Cant Keep Water Out Of My Lower Unit!

What was the condition of the driveshaft in the area where the seals ride? If it was at all pitted, rusted, not perfectly smooth and intact, you're gonna suck oil out of there regardless of the new oil seals.

The fix to that is to drive a couple of stainless steel "Speedi-Sleeves" (aka "Redi-Sleeve") over the damaged sealing surface to provide a new area for the seals to ride on.

The oil seal in the shift shaft bushing can definitely be a source of leakage, but it would have to be in bad shape to cause a lot of "milk" in only one run.

The driveshaft seal area, however, is a likely suspect as the vacuum formed under the water pump base by pumping action will very rapidly suck oil out, which gets replaced with water.

Just a thought..........ed

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

iam going to look for these "redi sleeves" the shaft had some wear on it, not pits but WEAR like grooves worn out. is that a marine part or what never hears of them, they make something similar for rear axles on a car, they're call save an axle, moves the outer bearing by spacer so it not riding on the worn section. i hope this works get nervous every trip now....

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

also anyone happen to know my shaft sizes? 1970 mercury 650 4 cyl 2-stroke

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

iam goin to mike the drive shaft, has anyone ever done this? how do i get the sleeve all the way down the shaft

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

I think you have it my shaft was beat an thinkin the same thing hope i can figure out the right size and get it good. if you have any advice on install i would love it!

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

ok just dropped the lower unit ripped it all apart the drive shaft has 2 smale scores all the way around but when i took it out the cavity w/ the shift shaft was all milky please help!!! what do i change?

 

[Moody Blue]

Re: Cant Keep Water Out Of My Lower Unit!

Again, for the low cost of the shift shaft bushing assy I would change it while you've got it apart.

If its NOT the source of the leak you will only be out a few bucks and will have eliminated a potential source.

 

[emckelvy]

Re: Cant Keep Water Out Of My Lower Unit!

Yeah, if the shift shaft seal is that bad, change it out. The new bushing assy comes with an O-ring and later-style seal already installed.

Note, Do Not pull out the shift shaft when you're working on it, it's a real pain to get it back in there without disassembling the lower unit.

Don't have a heart attack, though, if it accidentally comes out. We can walk you thru the reinstallation process..........ed

p.s. on the driveshaft, if the 'scoring' is even all the way around and the lips of the seals can still ride OK on the shaft, it's not ideal but may still work. I expect you'll know more after you get the bushing replaced.

 

[Moody Blue]

Re: Cant Keep Water Out Of My Lower Unit!

I've read somewhere (probably here) that you can install 3 seals in place of the two seals in the lower waterpump base. This would then change the location where the seals ride on the driveshaft. Have not tried it but may need to.

 

[emckelvy]

Re: Cant Keep Water Out Of My Lower Unit!

You'd have to find thinner seals of the right O.D. and I.D. That might be a challenge. Plus there's no guarantee they'll end up riding on a part of the shaft that's any better.

BTW the shaft diameter can be measured with a set of vernier calipers if the calipers can read in increments down to .001" (a set of dial calipers or even a cheap digital one would get plenty close).

The stainless repair sleeves have a size range for fitment, so you don't have to get down to .0001" accuracy, just as close as possible.

 

[thejeep007]

Re: Cant Keep Water Out Of My Lower Unit!

thank you every one, update, dropped lower unit the other day threw some comp air in lower unit found another hair crack bubbling on cavity behind shift shaft all the way down, packed water weld in there (great stuff) took her out last night MORE WATER!!! ran more air in it today w/ some leak find bubbles shift shaft seal bubbling a little. made a tool by putting 2 blobs of weld on a nut & welding nut to deep docket worked great... now on the hunt for bushin and seal, wish me luck fellas about to sink her!

 

[1976SRV190]

Re: Cant Keep Water Out Of My Lower Unit!

OK IVE CHANGED THE WATER PUMP BASE ON MY 1970 650 4CYL 2-STROKE AND STILL GETTING MILK AFTER EVERY RUN... THE BEARING CARRIER O-RING WAS ALSO REPLACED, WHAT ELSE COULD IT BE THE ONLY THING I CAN THINK OG IS A SHIFT SHAFT SEAL, MY SELCO GREW LEGS AND RAN AWAY ANY ONE HAVE ANY THOUGHTS ON IF I AM GOING THE CORRECT PATH AND ANY QUICK RUNDOWN OF CHANGING THE SHIFT SHAFT SEAL AFTER LOWER UNIT OUT. THANK YOU:confused

IF it is a Mercury 650 from 1070, then go here to see what is available.

http://www.eastcoastmarineservice.com/197071Merc650.htm

replace the entire lower unit seal kit.