old school OMC impeller help w/ pics

[Redrig]

Hello,

I recently tore into my 1977 OMC electric shift, I have to replace my lower and while I am in there I am going to replace the raw water pump as well.

I took the impeller housing off and marked everything, while I was cleaning off all of the grease unfortunately I wiped off my mark for aligning the housing into the upper.

I am assuming that this has to lined up correctly for the water to flow right and I have no idea how to line up.

in these pics I have numbered the different water passages on the impeller housing as well as the bottom of the upper where it mounts into.

can anyone tell me which passages or numbers that I need to align when I am putting this back in, sadly enough my manual doesnt cover this.

below are the pics of them, thank you in advance for any help

 

[Howard Sterndrive]

Re: old school OMC impeller help w/ pics

the 4 bolt holes aren't symmetrical, so you couldn't install it wrong if you tried

 

[captk]

Re: old school OMC impeller help w/ pics

Those splines in there dont look too healthy. check them real good or they will let go. how are the w/pump shaft splines?

 

[Redrig]

Re: old school OMC impeller help w/ pics

the 4 bolt holes aren't symmetrical, so you couldn't install it wrong if you tried

awesome thank you, didnt even notice that. one other question, when installing impeller should I point the the vanes in the direction of WITH the rotation or AGAINST the rotation?

 

[Redrig]

Re: old school OMC impeller help w/ pics

Those splines in there dont look too healthy. check them real good or they will let go. how are the w/pump shaft splines?

splines on the water pump shaft are good, but yes the splines in the upper dont look good in that pic. is there anything I can do to help preserve them ?

 

[Howard Sterndrive]

Re: old school OMC impeller help w/ pics

start the impeller vanes in the same direction they will be going. KY jelly or other water soluble lube on them.

Plenty of good marine grease in those splines will aid survival.

 

[Redrig]

Re: old school OMC impeller help w/ pics

start the impeller vanes in the same direction they will be going. KY jelly or other water soluble lube on them.

Plenty of good marine grease in those splines will aid survival.

after seeing that comment on the splines, I got in there and took a good look and cleaned them up, they are fine they will probably outlast the boat.

thanks again for the reply Howard

 

[Redrig]

Re: old school OMC impeller help w/ pics

also,

I have seen in quite a few threads from searching previously that there has been a few debates over these electric shift and thier 'default shift mode'

some say that with no power to the outdrive that the drive will 'default' into Forward so that you can get home if you have a shifter problem. this is not the case either of my 2 lower units, 77 and 75.

both require 12 volts to either the green or blue wire for forward or reverse.

no power, no shift.

 

[captk]

Re: old school OMC impeller help w/ pics

the forward default was only in the hydro electric outboards not in stern drive