Oh boy, milkshake in lower unit. 74- 70hp Johnson

[blueboat1]

I was doing some some last minute check getting the boat ready fror some fishing. I decided to check the lower unit oil, much to my suprise it was a milk shake. it's a 1974 70hp Johnson. How hard is it to replace the seals in the lower unit. i have done head hasket, impeller, thermostat, and carbs and they didnt seems to be too much of a challenge. is this likely something i can do, any idea on $$. Thanks in advance. last time i ran it i did not notice any rainbows so i believe it is not loosing any greese/oil just pulling in water. is that possible? could too much pressure from the earmiffs cause this?

 

[Specks n Reds]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

 

[blueboat1]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

I will check it but i do remember clearplastic rings as i pulled the screws out. Most oif the rubber parts on the motor seem to be hard not soft, When i got it it had been sitting for a long while (by the looks of all othe wasp and mud dobber nest in/on and around the boat/motor. Thanks. If i do need to replace the seals are they a bear ?

 

[Specks n Reds]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

 

[james1]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

If you have done the other work yourself then replacing the gearbox seals shouldn't be a problem.Replacing the O rings on the inspecion & filler screws would be a good idea as well but I am sure that your seals r your only real problem.<br /><br />Good luck!!!

 

[OBJ]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

Tin Can....I've heard it called a lot of things....but never ever a milkshake LMAO!!! I like it.

 

[12Footer]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

It's not that big of a deal (usually). It may just be a prop seal, in which case you just need to install the new seal with the l/u in place.<br />Do a pressure test (no more than 5PSI so you don't actually blow a seal).<br />Do it with the leg submerged in a drum if possable, and look for bubbles. Bubbles will come from the pressurised case wherever a seal has failed.<br /> Here is a thread that may be of further help...<br />And don't be so drepressed about it. Instead of grenading your gear case, you saved your investment by a bit of quality time invested in Preventive Maintainence..Kudos!

 

[blueboat1]

Re: Oh boy, milkshake in lower unit. 74- 70hp Johnson

I guess that is a good way to look at it. I just purchase a house so there isn’t much extra to keep the old tin can in the water and if I would have fried it I would have been very bummed. I'll do the pressure test (5lb) and see what comes up (literally). I hope it's simple. I may have found the cause. The prop had a chunk taken out of it. Since I was in between 30 and 500 ft of water, i am not sure how it chipped but it did. I have a brand new prop to put on it but I wonder if the out of balance prop on the last trip did it? Live, learn and spend more money! Thanks for all the help.<br />Scott