H35 vs hs40 what's different

[VintageMoneyPit]

What's different between an H35 and hs40 is it just the bore or stroke. Or both. Can you put an hs40 piston in an h35.

 

[capguncowboy]

The piston will have a different diameter (HS40 will be slightly larger).

The intake and exhaust are also reversed on the HS engines.

 

[creia]

capguncowboy is correct on the piston size difference, except for the 1983 serial # ONLY where they were the same size THAT YEAR ONLY
As far as the stroke, the HS40 had a longer stroke for all production years.
Source: Tecumseh Engines Mechanic's Handbook 3-10 HP 4-Cycle Engines printed in 8/1988
Michael

 

[minikenny]

capguncowboy is correct on the piston size difference, except for the 1983 serial # ONLY where they were the same size THAT YEAR ONLY
As far as the stroke, the HS40 had a longer stroke for all production years.
Source: Tecumseh Engines Mechanic's Handbook 3-10 HP 4-Cycle Engines printed in 8/1988
Michael

I read the same book differently.

HS40 stroke, all years: 1.938
HS40 bore, all years: 2.625

H35 stroke prior to 1983: 1.844
H35 stroke 1983 and later: 1.938
H35 bore, all years: 2.500

 

[creia]

I read the same book differently.

HS40 stroke, all years: 1.938
HS40 bore, all years: 2.625

H35 stroke prior to 1983: 1.844
H35 stroke 1983 and later: 1.938
H35 bore, all years: 2.500

minikenny is correct- I stand corrected.
Michael

 

[minikenny]

It's capguncowboy who had it right: HS40 bore is larger.

I figured you had good info, you just had bore & stroke reversed. :thumbsup:

 

[creia]

It's capguncowboy who had it right: HS40 bore is larger.

I figured you had good info, you just had bore & stroke reversed. :thumbsup:

Yes, I DID have good reference information, however, reading it PROPERLY was another story. Hey, at my (advanced) age I'm going with the "I had a senior moment" excuse! LOL
Michael

 

[ole4]

I use that a lot lately.