1967 Johnson 40 HP

[dozerII]

A friend has a 67 40 horse johnson that is taking water in the L/U. He changed the oil and it was milky. I told him I would take a look at it so I pulled the unit and brought it home. This morning I drained the oil and it was mily again and has not been in the water since he changed it so it need flushing out. I made an adapter to fit the vent hole and put in a tire valve, set the L/U in a tub of water over top of the water pump and put 15psi in it. No leaks were visible. I got called to work and left it in the tub till I came home 7 hours later and it still has 15 psi in it. What am I doing wrong checking it, or where could the water be coming from?
Any help would be appreciated.
Thanks Glen

 

[Xcusme]

Re: 1967 Johnson 40 HP

Well, with all being equal...since you've changed the Vent valve and after 7 hrs you don't show any water, the vent washer was changed.

If thing to do is change the washers and rechek.

 

[boobie]

Re: 1967 Johnson 40 HP

When it's in the water under pressure rotate both the d/s and p/s over and see if anything changes as far as holding pressure . If it's got a shift rod also work that between fwd and rev.

 

[dozerII]

Re: 1967 Johnson 40 HP

Thanks for the replys Boobie and Xcusme. I forgot to mention it is and electric shift i don't know if that matters. I rotated both shafts slowly while it was in the water and got no bubbles. Next time I get a chance,(have to work the next 3 days) I will switch the pressure adapter to the fill hole and put the plug back in the vent hole and see if that makes a difference. What is the best way to flush the gear housing varsol, diesel ?
Thanks again Glen

 

[Evinrude Boater]

Re: 1967 Johnson 40 HP

Reusing the drain and vent plug gaskets is the most common cause water intrusion.

 

[boobie]

Re: 1967 Johnson 40 HP

If it's an electric shift also check real close around the shift wires that come out of the L/U.

 

[dozerII]

Re: 1967 Johnson 40 HP

Thanks for the replys, I will check out the ideas on my next days off.
Glen

 

[1946Zephyr]

Re: 1967 Johnson 40 HP

Well, it's likely the leaks were in the hole where you put in the tire valve at. If the leak stopped by changing that, then it sounds like you found the problem. If you don't see any bubbles with 15 psi, then that's a pretty darned tight lowerunit. I would put new oil in the lower unit, with new washers on the plugs and see if water is still getting in.