OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

[ekmanspiral]

Pretty much stated my question in the title. I have a 1978 boat with everything original except the lower until and exhaust housing. The lower unit has the small zink next to the impeller intake holes. I'm having some issues with the upper gear house and am wondering about purchasing a 1981 - 85 complete upper gear case. Will it bolt up ?

thanks,
Neil

 

[run2car]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

78-85 should be the same housing. I'm curious about the zink, sounds like a 77 or earlier.

 

[ekmanspiral]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

The zinc is next to the idle relief port (my memory's not so good). I looked up the post where I found the info:

see the rectangular zinc anode in this pic below the V6 decal next to the idle relief holes... it is only on full mechanical. the hydromech drive looks identical except no rectangular anode:

fairly

Neil

 

[Howard Sterndrive]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

The lower unit has the small zink next to the impeller intake holes.

that lower unit is 1982-1985 then

It will "bolt up", but not work without additional parts
a 1978 boat has the wrong shift converter and lacks the ESA (electronic shift assist) system required to shift a 1982-1985 lower unit.
So you would need a later shift converter and an ESA system (switches, module, wiring)

 

[ekmanspiral]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

The boat had the 82-85 lower unit and exhaust housing bolted up to the original (78) upper case and intermediate housing. I've only owned the boat for a couple of months but I was told that this was done 2-3 yrs previous. What does the esa look like. Where does the esa connect to the shift system?

 

[Howard Sterndrive]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

what is the symptom?

 

[ekmanspiral]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

The symptom was water in the upper gearcase. I have it apart and the bearings on the upper vertical shaft do not move very freely. Also the splines on the water pump shaft and upper vertical shaft look a little questionable. Also the bearing house is severely corroded. Adding up the cost of the parts I am weighing the option of buying new parts and having a shop install the shafts in the gear housing or buying a used complete upper gear case. I'm going to take the parts into a shop on Monday and get more of an idea.
Here are some pics-

 

[Howard Sterndrive]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

I'd look for a good used upper, and get a new waterpump shaft. ebay item 220570869709 will show you what an ESA is.
That item is the conversion kit for hydromech to mechanical. I suspect your boat already got that kit at some point in its life.

Seloc manual has a chart of all upper gear ratios, so you'll be able to see what other years/models used the same tooth count as your upper.

 

[ekmanspiral]

Re: OMC 800 will a 1981-85 outdrive bolt to a 78 intermediate housing?

Thanks for the link. I do have an ESA installed.
I just got back from a marine shop in El Cajon. So now I have to add up the parts and labour and figure out if I'm better off getting a used upper case (basically sight unseen) or redoing mine with new bearing,shafts, seal kit and labour. The gear set is still good. I'm looking at around $800 + at this point. I'm leaning in this direction. Where is a good source for the bearings, shafts and housings? I found some on this site and some on boats.net. Are there other places and is there quality issues with any of the aftermarket stuff?
thanks,
Neil