Scott Atwater, 1959 7.5, questions

[davidk]

Hey, a couple of questions for S/A folks out there:
I’m looking for a seal. Looks like this one got pinched by some p/o. It’s thick and fibrous:

Had trouble getting the driveshaft our of the powerhead. What would cause someone to weld up this mess?

A friend of mine would say "The enemy has been in here!"

How about diaphragm material for the fuel pump?

More questions to come. Thanks for any responses.

[shoestringmariner]

Cant help with much, but is that shaft welded all the way around (as if broken in two) or was it simply welded to the part it was splined into. In any case it is a mess. Pretty heavy heat affect zone

[davidk]

Welded all the way around. It IS a mess. I ground it down, but I probably need to find another driveshaft.

[davidk]

Welded all the way around. It IS a mess. I grounded it back some, but I probably need to find another driveshaft.

[shoestringmariner]

It might clean up ok, but I’d be more concerned with it being bent. Might tear more stuff apart or wear things out prematurely if it is not 100% true. I dont know enough to say however, not knowing these motors and how fussy the fit up of everything is.

[frankr]

The only reason I can think of is the splines are gone out of the crankshaft and they "fixed" it by welding it together. Take a look up in the crankshaft and see if I’m right. Looks to me like you need a drive shaft AND a crankshaft. Or another motor.

[retiredoz]

The seal ring is PN 3745-1893, indicates it was used on 5-hp (and most likely 7.5s) starting in ’54. The driveshaft would have to come from another ’59 7.5 – I believe the one and only year it was made. Maybe the ’58 is similar, the ’60 was the lowboy, entirely different motor.

[davidk]

quote FrankR:

The only reason I can think of is the splines are gone out of the crankshaft and they “fixed” it by welding it together. Take a look up in the crankshaft and see if I’m right. Looks to me like you need a drive shaft AND a crankshaft. Or another motor.

Wow, I think you are right (as usual) Frank! Have you seen that done before?

I have a 10 hp Scott that seems to share a lot of parts. Looks like the 10 hp powerhead could bolt right onto the 7.5. Different year, different drive shaft. The 10 has the water pump up higher in the leg.

[retiredoz]

It does appear you could bolt the 10-hp powerhead to the 7.5 tower, but you may be SOL on the driveshaft. Looking at the parts list, except for some minor odds and ends, the only parts peculiar to the ’59 7.5 are the head, intake manifold, and (unfortunately) the driveshaft. Probably the driveshaft is modified to drive the pumps on top of the gear case instead of the higher elevation.

[mogems-yahoo-com]

If all else fails… Try a circa 1973 Harley-Davidson Sportster pushrod tube (cork) seals. George 856-447-3641

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