OMC parts 800 / Cobra outdrive drawings * How to videos

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OMC Parts repair or replace ?

Question is replace or repair OMC outdrive parts

Components in question are listed below and the reasons behind the answers
  • OMC 400-800 upper gear case
  • Cobra, stringer electric or 400-800 series propeller shafts and drive shafts
  • Broken 800 series and Cobra lower unit gear-cases
  • Repair method listed below and in video are that of the author (Wayne Coll) the tech service representative for T.C.
  • Electronic/Marine and are not listed in Seloc or service manuals to my knowledge.

By author Trish Dougherty

OMC 400-800 upper gear cases are a yes and no answer here why.

Water pump housing area or section of the case often break from having water frozen over winter in northern locations. Repair not recommended
This welding repair can work but unit must be welded in the absence of oxygen a special chamber with enough argon and helium flowing though the welding box and a special tip has to be made to get at it.

Aluminum alloy material out-drive is made from has impurities in it and 90 % of the time after grinding or machining the weld area the case will have pinhole leaks that must be filled with 609 Loctite compounds. In general the cost to weld and Loctite is more than purchasing a used case from T.C. Electronics/Marine.
Rear small bearing has spun in back area of gear case leaving the press fit area lose.

This repair is recommended if play in outside bearing race and retainer area of case is less than .005. the area need to be wire brushed or sandblasted and cleaned with primer and 680 Loctite applied to bearing outside race and press fit area. If there is too much play, say more than (.007) best to have a sleeve insert made from stainless steel installed in bearing retainer section of gear case with the 680 retaining compound.

Clean bearing and seals of any 680 loctite

Clean bearing and seals of any 680 loctite

Cobra, stringer electric or 400-800 series drive shafts are a yes and no answer here why.
Lower gear-case drive shafts 1-1/2 inch in diameter like the one used by old electric shift 1964 to 1977 seldom bend the seal area may have groves in shaft in one or two places but the shaft is straight in general. Repair is recommended but the repair is done not to the shaft but to the top bearing retainer and the Gear-head you rebuild the parts. Bearing carrier area of the gear-head should be machined to hold 3 seals. seal area will now be find it self location in a different spot on the propeller shaft. *Note OMC seal kits only come with 4 seal this method will require purchasing one seal.

OMC parts repair electric Stringer 800 Cobra lower gearcase

Electric Stringer lower gearcase

Top bearing retainer must be rebuild with seal left 1/16 outside or inside seal retainer area seal and retainer area must be coated with 680 Loctite to hold the partially pressed in seal in place. Note seal placed in bearing carrier 1/2 with 680 compound will hold up to 1,200 pounds per square inch of seal. I have used this method on over a thousand units the last 20 years and never had one leak on pressure or vacuum testing.

Do not forget about our OMC help me page that has links to all our exploded view outdrive drawing and exhaust manifold help pages.