Scott Atwater, 1959 7.5, questions

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #1123

    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.

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    shoestringmariner


    Replies: 258
    Topics: 53
    #13434

    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

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #13436

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

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #13437

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

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    shoestringmariner


    Replies: 258
    Topics: 53
    #13438

    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
    frankr


    Replies: 5300
    Topics: 48
    #13439

    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.

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    retiredoz

    US Member - 1 Year
    Replies: 487
    Topics: 47
    #13443

    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.

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #13513
    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.

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    retiredoz

    US Member - 1 Year
    Replies: 487
    Topics: 47
    #13514

    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.

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    mogems-yahoo-com

    US Member - 2 Years
    Replies: 37
    Topics: 22
    #13516

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

    frankr
    frankr


    Replies: 5300
    Topics: 48
    #13530
    quote 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.

    You ask if I have seen that before. Are you kidding? This is salt water down here. Seen it or similar lots of times. Got stuck with a few trade-ins that have been "fixed" in creative ways too.

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #13534
    quote FrankR:

    You ask if I have seen that before. Are you kidding? This is salt water down here. Seen it or similar lots of times. Got stuck with a few trade-ins that have been “fixed” in creative ways too.

    Yeah, this motor came as a "gift." Looks great cosmetically. Has good spark. Looked like I could gas it up and go. As I waded in, I found the full lines stiff and cracked, and the fuel pump corroded. Seemed a reasonable fix until I tried to get at the impeller(s).

    I’m glad it was a poor welding job. Made it easier to get apart. Kind of hard to change the impeller if you can’t disassemble.

    Mumbles
    Mumbles

    Canada Member - 2 Years
    Replies: 4548
    Topics: 432
    #13536

    If the splines are gone in the crank shaft, a socket can be welded onto the end of it and then the drive shaft gets ground and filed to fit the socket. Or it can be filled with epoxy while reassembling. It’s not a correct repair but it works.

    The seal is made of thick cork. It’s a lot bigger and thicker than a push rod seal.

    Ollie carries diaphragm material for the pump.

    http://www.pfs-ware.com/Parts/OllieParts.htm

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    davidk

    US Member - 2 Years
    Replies: 346
    Topics: 156
    #13537
    quote Mumbles:

    If the splines are gone in the crank shaft, a socket can be welded onto the end of it and then the drive shaft gets ground and filed to fit the socket. Or it can be filled with epoxy while reassembling. It’s not a correct repair but it works.

    The seal is made of thick cork. It’s a lot bigger and thicker than a push rod seal.

    Ollie carries diaphragm material for the pump.

    http://www.pfs-ware.com/Parts/OllieParts.htm

    intriguing socket fix, Mumbles! Thanks for the info and resources.
    -DK

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