Trashed my 800 lower. Options?

Chevy13s

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Jul 7, 2007
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Well I just got the boat this year and replaced the motor (originally 5.0 to a 5.7 with a 1979 omc 800) and a bunch of other stuff to make it river worthy. The reverse did not work probably due to a gear problem as I checked everything else. I was planning on replacing the forward and reverse gears with the coupler this winter. So anyway I was out this past weekend on the river at full throttle when suddenly the boat basically went into nuetral. Thank god I didnt blow the new motor. I dropped the lower to find the shaft sheared just below the bearing retainer that mounts to the top of the lower.

So now I am thinking with the cost of the gears, shaft, bearings, seals, and the fact that half the fin on the bottom is broke off maybe I should just get a whole replacement lower? The cheapest I could find was $1700 on ebay. Any Ideas as to where I could get the best price?

Thanks Guys
 

whywhyzed

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Re: Trashed my 800 lower. Options?

1979 was hydromechanical. Is your lower still a hydromechanical type? (easy to verify - hydroshift lowers have no zinc beside the six idle relief holes, mechanical shift drives have a zinc) If it is hydromechanical...$1700 is only going to get you started...need to add an ESA system, change the shift converter, buy a mechanical shift cable for $350 etc.etc...
you have another PM
 

Chevy13s

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Re: Trashed my 800 lower. Options?

I know I need a new shift cable because mine is trashed but why do I need to change the shift converter? What is ESA?
 

aerwin

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Re: Trashed my 800 lower. Options?

was it the water pump shaft? that is very common, it happend to me too, cruising along then pow and then nothing. a full mech needs the ESA to operate properly, it cuts the engine voltage to coil for a split second while you are shifting to let the gears engage easy. the hydro, 78' to 81 or 82 didnt have it. try to fix the one you got, if water pump shaft then its a peice of cake, do water pump also. the hydro mech shift cable is easier to find. and yes they are very pricy
 

Chevy13s

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Re: Trashed my 800 lower. Options?

On that diagram of the lower it is the #8 shaft. It sheared at the thick part where I think needle bearings ride above the big screw type threads on the shaft. There wasnt much left of the bearings either. One big black mushy mess. =(

It has the micro switches on the shift converter which i guess is the esa and it is a hydromechanical shift.
 

whywhyzed

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Re: Trashed my 800 lower. Options?

It has the micro switches on the shift converter which i guess is the esa and it is a hydromechanical shift.

that doesn't make sense - the microswitches were NOT used with hydromechanical - need to find out which lower unit you have before you buy anything or you might open a real can of worms of mismatched parts - the zinc or no zinc thing is the best way to I.D. yours

The shift cables are different between the 2 types as well.

Finding the shift cable for a hydromechanical is tough..... tougher than finding a cable for the mechanicals. I don't think anyone ever reproduced the hydromechanical cables the way GLM did with the mechanical cables.
 

Chevy13s

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Re: Trashed my 800 lower. Options?

It has the zinc plate in the bottom of the outdrive around where the exhaust goes into the exhaust housing. There is no zinc plate around the idle relief holes. I have the lower removed from the exhaust housing so I can take a pic of something if you tell me what you want a pic of exactly.

thanks
 

Boomyal

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Re: Trashed my 800 lower. Options?

Notice red arrow pointing to zinc. This is an 800 Mechanical shift. The HydroMechanical does not have this zinc. This one uses a different shift cable and shift converter box plus it uses the shift interupt switches on the converter box, than the HydroMechanical drive.

You can swap either of these units from the electric shift drives (excluding high profile) thru the end of the stringer line. You just need all the right bits and pieces that go with each one.

The Hydromechanical was used from '78 to '80/81 and the Mechanical from 80/81 to the end in '85/'86.

OMC.jpg
 

whywhyzed

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Re: Trashed my 800 lower. Options?

So lacking that zinc, means you have a hydromechanical shift drive. Most of those were converted by OMC dealers to full mechanical lowers in the 1980's. Yours was not so your options are:

1. Buy a mechanical lower and perform the conversion - which requires a mechanical lower with shift cable, change of converter housing behind engine to ESA compatible unit (eBay), the installation and wiring of an ESA system (ESA module, switches, wiring- also eBay)
-or-
2. Buy a used hydromechanical 800 series lower (15 spline propshaft- don't get a 400 series 13 spline) - throw it on and go boating
 

THE BEEF

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Re: Trashed my 800 lower. Options?

Chevy13
I have the information you might need to convert. I P M you with my # if you want to call.
Beef
 
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