1950s johnson 7.5 hp leaks lube from lower unit

[dark cloud]

first post hello to all ! When I first bought this old engine I changed the lube in the lower unit it was milky and almost empty, I replaced the rubber washers on the drain plugs they where shot thought that was it. after a couple of times out on the lake I pulled the engine from the boat and laid it down on a trailer and lube started leaking out of the water intake I think, the large hole down towards the prop. not a small leak and not black but clear lube.
Any help appreciated

 

[tashasdaddy]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

a picture of where it was leaking would be a great help.

 

[dark cloud]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Not that good with a computer yet. looked at a diagram and I think its the exhaust port, one large hole at bottom of lower unit.
Thank you

 

[wbeaton]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Sierra 18-2679 Gear housing Seal Kit

http://www.iboats.com/mall/partfind...&gd_poid=110554&gd_row=5&**********=351594146

When you laid it down gear oil seeped out of either or both of the shiftshaft and/or driveshaft seals. There was post about resealing a QD-16 lower unit on here the last few days. Read it. Its the same procedure as your motor.

 

[steelespike]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Could be exhaust residue.With the motor upright open the drain if lube is creamy looking like coffee with cream you have bad seals and the seal kit suggested is needed.If not too bad some run them as is and just change the lube more often.Synthetic lube will polute less.

 

[dark cloud]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Thanks for the replies. after reading the post as suggested not sure I want to jump into all that. The engine had set for many years with little lube in the lower unit, is there any chance that with some use and changing the lube often the seals could get better? The engine runs great and even after setting for a long time only needed fresh gas. I am good with mechanics but new to boat engines. I am sure I could do the seal replacements on the lower unit but it seems others have had lots of problems with finding some of the gaskets and cracking the housings. Only ran it a couple of hours maybe a little better work out could help?
John

 

[wbeaton]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

You can't fix bad seals. Its either replace the seals or check/change the lower unit oil after every outing. However, if it leaks a significant amount of gear lube like you said then you are really just waiting for failure if you don't do them.

The reseal isn't as bad as it sounds. You just need to be careful and use the proper tools. Total cost of tools is under $10. Seal kit is about $30. May take you a couple hours since you've never done one before. You need to replace the impeller anyway since its sat for so long. You might as well do the seals while you have the lower unit off. IMO

Also, assuming you have a 1954-58 Johnson/Evinrude the parts are readily available. As for cracking the lower unit housing, that was due to an improper tool being used. Those things happen. Just be careful and you should do just fine.

At this point you should probably post your model number. It starts with the letters AD.

 

[dark cloud]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Thanks I am not a young man should know to do it wright, one problem the transom bracket has been changed it has a evinrude bracket. there is a round 50 cent piece size circle on the side of the motor with the numbers 1542580 on it. I can find no numbers that start with AD, any ideas where to look.

 

[wbeaton]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

I assume that's the S/N, which makes it a 1957. Is it red (Holiday Bronze) with a white top and strip on the side? Like the one in the attached photo.

 

[dark cloud]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Yes real close. the face plate is a little different I think will have to look. spent two hours trying online to find SN instead of model numbers. Is there a web site that I can use to look for serial numbers?
Thank You
John

 

[wbeaton]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Is there a web site that I can use to look for serial numbers?

Not that I know of. Go to the following website and browse the old ads to find your motor. Johnson's usually put the S/N number on the plug while Evinrude usually put the model number. Sometimes, I think ,they put both.

The Johnson 7.5 hp was produced from 1956-58.

1956 = Red top with red sides and white side strip
1957 = White top with red sides and white side strip
1958 = Red top with white sides and red side strip

 

[Buddy1956jad10]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Just want to be sure , does the gasket and seal kit above work for a 1956 7.5 ad-10 m johnson?

 

[bbstacker1]

Re: 1950s johnson 7.5 hp leaks lube from lower unit

Old thread from 2009, you should start a new one with your question(s), but yes the gasket and seal kit should be the same.