68 Evinrude Lark X 40hp

[gusthewonderslug]

Hi all
I seem to have a slight leak from my lower gearbox, I have replaced the lip seal already and replaced the O rings on the retaining bolts but seem to still have a slight leak.
Are the original o ring seals a special part or just standard O rings?
Many Thanks
Gus

 

[F_R]

Re: 68 Evinrude Lark X 40hp

Reasonably sure they are standard nitrile O-rings. Are you sure it is leaking and not just fuel drainage from the exhaust? Pressure test it.

 

[gusthewonderslug]

Re: 68 Evinrude Lark X 40hp

Pulled the rear bearing assembly apart last night lower unit full of water
Notice some pitting on the output shaft and have dressed id with wet n dry
I will replace the o rings on the retaining bolts and on the housing
Can I use ATF instead of the prescribed oil.
Gus

 

[boobie]

Re: 68 Evinrude Lark X 40hp

No ATF. Get the proper oil. As F_R said, get it pressure tested and take the guess work out of it.

 

[gusthewonderslug]

Re: 68 Evinrude Lark X 40hp

I take it that my local stealer will be able to pressure test it?

 

[kfa4303]

Re: 68 Evinrude Lark X 40hp

Not sure what "stealer" is? Must be an Aussie term. You can actually use something as simple as a bicycle pump. Use the nipple off of the hand pump used to fill the gear case with oil and attach it to the end of the pump. You can then give it a few pumps to build the pressure to about 10psi. You can then let is sit for about 30 minutes. If your still at the initial psi, you should be ok. However, if it drops you know you have a leak. Performing a vacuum test is nice, but a little harder to pull off using DIY bits and pieces. Of course, the motor is +50 years old so a leak here, or there is to be expected. I've driven myself mad trying to get my LU perfectly sealed on my vintage motors. Some do dome don't. I usually just check the oil every few trips and change it as needed. Now, before you do all of that, you may get lucky and simply need to replace the white, nylon crush washers which are usually the main culprit when it comes to leaks.

 

[gusthewonderslug]

Re: 68 Evinrude Lark X 40hp

Not sure what "stealer" is? Must be an Aussie term. You can actually use something as simple as a bicycle pump. Use the nipple off of the hand pump used to fill the gear case with oil and attach it to the end of the pump. You can then give it a few pumps to build the pressure to about 10psi. You can then let is sit for about 30 minutes. If your still at the initial psi, you should be ok. However, if it drops you know you have a leak. Performing a vacuum test is nice, but a little harder to pull off using DIY bits and pieces. Of course, the motor is +50 years old so a leak here, or there is to be expected. I've driven myself mad trying to get my LU perfectly sealed on my vintage motors. Some do dome don't. I usually just check the oil every few trips and change it as needed. Now, before you do all of that, you may get lucky and simply need to replace the white, nylon crush washers which are usually the main culprit when it comes to leaks.

Stealer = Dealer

 

[kfa4303]

Re: 68 Evinrude Lark X 40hp

gotcha yeah, stay away from those guys. If you do a search here in the forums, you'll find several threads on DIY pressure testers and testing procedures.