Drive shaft o ring on mc1

[danield]

Getting ready to reinstall lower half on mercruiser mc1, when I pulled lower unit there was no o ring on drive shaft but there is a o ring groove on shaft, I took a light and searched the upper half and can't find o ring any where, guess my question is did all the mc1s have the oring or was there some that didn't, have searched all through the upper half and can't find oring. any ideas

 

[Eric 3.7LX Alpha 1]

Re: Drive shaft o ring on mc1

The MC-1 did use the O'ring. Newer drives have eliminated it and the groove has been eliminated..... Many do not use the O'ring on their older drives .

It is not needed.

 

[danield]

Re: Drive shaft o ring on mc1

thanks Eric seems I have heard it wasn't necessary

 

[thumpar]

Re: Drive shaft o ring on mc1

Every time I have read a post about this from a knowledgeable person they have said not needed and not to use.

 

[ziggy]

Re: Drive shaft o ring on mc1

just to help confirm.
yep the o ring is not needed. grooved shaft or not.
best i know, the o ring groove was eliminated on the r or the mr drive. i think the mr drive. anyways. another way to look at it is if ya were to replace the lower drive shaft. the new one would come less the groove and no way to install the o ring.
my 75 has the groove and i've not used the o ring in at least the last 5 years. no ramifications.