Tecumseh Engine...what is it?

#1
HI Guys,
Newbie here as a result in trying to relive my youth! Got a Rupp minibike, possibly a roadster, with an engine that I dont know if it goes with this bike or not. There was a Kohler engine on it but this one was included as well. If you would kindly look at it and potentially give me an idea of what it may be, and perhaps figure out if it was to be with this bike. Thanks in advance for your technical input!!
 

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mustangfrank

Well-Known Member
#2
HI Guys,
Newbie here as a result in trying to relive my youth! Got a Rupp minibike, possibly a roadster, with an engine that I dont know if it goes with this bike or not. There was a Kohler engine on it but this one was included as well. If you would kindly look at it and potentially give me an idea of what it may be, and perhaps figure out if it was to be with this bike. Thanks in advance for your technical input!!
It's a Tecumseh HS50, not original to a Rupp, it's a Sears model number. It would look and work fine on your Rupp frame, PTO length might be a factor depending on clutch choice, certain Rupp Tecumsehs had a longer PTO.
 
#3
It's a Tecumseh HS50, not original to a Rupp, it's a Sears model number. It would look and work fine on your Rupp frame, PTO length might be a factor depending on clutch choice, certain Rupp Tecumsehs had a longer PTO.
It's a Tecumseh HS50, not original to a Rupp, it's a Sears model number. It would look and work fine on your Rupp frame, PTO length might be a factor depending on clutch choice, certain Rupp Tecumsehs had a longer PTO.
Thanks mustang! I have another HS50 but really thought this engine was smaller than the HS50.
Question regarding the original Rupp motor. I understand it more than likely had an HS40 on it. Would there be much size difference in the 40 vs the 50?
Also I have some HH60 engines and parts….would there be a substantial difference in carbs or would a carb off the 60 work on the50?
Thanks!
 

mustangfrank

Well-Known Member
#4
Thanks mustang! I have another HS50 but really thought this engine was smaller than the HS50.
Question regarding the original Rupp motor. I understand it more than likely had an HS40 on it. Would there be much size difference in the 40 vs the 50?
Also I have some HH60 engines and parts….would there be a substantial difference in carbs or would a carb off the 60 work on the50?
Thanks!
The HS40 & HS50 are identical in size, same longblock externally, the HS50 is a larger bore. Square shrouds versus older rounded shrouds can trick the eye maybe.

No idea on HH parts interchange, I don't mess with those much.
 
#6
Thanks for the help in defining it. I didn’t know about the craftsman number reference. Thanks again!
My intent is to get it in a project Rupp. Not sure of the model on that either but that’s for another forum.
after I get more into it, I’m sure I will be back for some guidance!
 

joshua. c.

Well-Known Member
#7
There is one dimensional difference between an hs40 and an hs50 engines, The hs50 is slightly wider than the hs40 due to a larger flywheel requiring a larger shroud. It will stick out on the right side of the bike a bit further than the hs40 but not enough to be an issue. side note the hs50's larger boar will give you a bit more power than the smaller hs40 and still looks somewhat original. I spoke with a rupp owner once who swapped out the hs40 for an hs50 for that very reason.
 

mustangfrank

Well-Known Member
#8
There is one dimensional difference between an hs40 and an hs50 engines, The hs50 is slightly wider than the hs40 due to a larger flywheel requiring a larger shroud. It will stick out on the right side of the bike a bit further than the hs40 but not enough to be an issue. side note the hs50's larger boar will give you a bit more power than the smaller hs40 and still looks somewhat original. I spoke with a rupp owner once who swapped out the hs40 for an hs50 for that very reason.
There is no dimensional difference between like HS40 and HS50 points engines, the square top shrouds are the same part. The round top shrouds with the aluminum flywheels are 1/2" narrower than a square top shroud with a steel flywheel. Direct swap the aluminum flywheel, cup and round top shroud over to the HS50 for looks or if a 1/2" additional width is even an issue.
 

joshua. c.

Well-Known Member
#9
the 1/2 inch difference in the shrouds is what I was talking about. I did state it was only slight and it wouldn't be enough to be an issue. the blocks are identical with the exception of the intake port.
 
#10
There is no dimensional difference between like HS40 and HS50 points engines, the square top shrouds are the same part. The round top shrouds with the aluminum flywheels are 1/2" narrower than a square top shroud with a steel flywheel. Direct swap the aluminum flywheel, cup and round top shroud over to the HS50 for looks or if a 1/2" additional width is even an issue.
I have 2 Hs50s with H35 shrouds, so H35 shrouds will fit as well.
 
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