Hole blown out of upper gear area - merc 260 alpha gen1

[CamaroMan]

My buddy bought a boat last month - the PO stated "it will do 50mph all day" on the ad...

2nd (short <5miles) trip back he hears a clacking sound from back.. lucky he was going slow inside break water.

Calls me up for a check, at first I thought perhaps lower shift cable had been set wrong resulting in the gears not engaging.

After doing some peeks inside moved to outdrive, noticed a 1/2 square hole in top facing aft -

Took off upper cap, gears worn down and oil is filled with bright shiny silver paste. One blew a hole right thru upper casing (!)

Could bad u joints cause this, improper alignment?

thanks

 

[achris]

[...Could bad u joints cause this, improper alignment? ...

Lack of oil, heavily contaminated oil, yes.

Uni-joints or alignment, no.

Chris.........

 

[tpenfield]

I think the PO forgot to mention that the boat does 50 mph all day . . . being towed on the trailer. Anyway, a new outdrive (or a substantial rebuild) is in your buddy's future. Probably doesn't matter what caused it since it all has to be fixed anyway.

 

[CamaroMan]

I think the PO forgot to mention that the boat does 50 mph all day . . . being towed on the trailer.

haha indeed!!!

any idea whether pre-alpha/mc1/mr type and alpha ones upper and lowers are interchangeable?

 

[Maclin]

If he really likes the boat then I would recommend a complete drive unit from SEI. What model/year is the engine and drive? I did not see any of that in the post.

 

[wahlejim]

Yes, alphas can go on MC1 assemblies IF the model year is in the correct range. Without doing more research, I do not know the years off the top of my head. Other, much more knowledgeable people on here know it though. I have an SEI 106 that replaced an MC1 drive. $1200 ready to go with the best warranty in the industry.

 

[achris]

Anything 1972 to 1990 is interchangeable. Full assemblies only. That it, a complete upper or a complete lower or a complete drive, but not internal parts to different models.

 

[Bondo]

Full assemblies only.

Ayuh,.... Except, the input shaft on the MC-1s runnin' behind In-line GM motors had a shorter shaft,....
Ya can't swap on a longer shaft drive,...
'n if ya used a drive with the short shaft on a unit needin' the more common longer shaft,... it'll eat the coupler out in no time,...

Once ya get up to the late-70s, the upper units can be swapped with different lower units,...
The vertical shaft spline count changed to fine splines, 'n the uppers, 'n lowers will swap after that point,...

The Gen.IIs in '91 ended the mixin', 'n matchin' in ole Mercs,...

 

[CamaroMan]

thanks guys - bought the fresh water one for 450 - exc condition.. seals leaking prob cos it stood for a few yrs.. put in new seals today and its curing overnight-hopefully upper will hold air 2moro. Where can air leak out from the upper, drive shaft seals, upper cover and large oring that seals the horizontal bits? vent hole and quad oring between units?

 

[achris]

... Where can air leak out from the upper. Drive shaft seals, upper cover and large oring that seals the horizontal bits? vent hole and quad oring between units?

And the front yoke seal.

Chris.......