What Tecumseh engine is this?

danford1

danford1

#1
#1
I have a Tecumseh engine. It has a pull start shroud that says it is a H30. (H30 35345S Ser 8076B)
All the H30's I saw had the exhaust coming out the clutch side. My exhaust is near the Mag side.
I suspect someone changed the shroud.
Can you guys identify this engine?
It runs Great what ever it is... Seems to have a lot of power for a 3hp...

Danford1

File_002.jpeg File_000 (1).jpeg File_001 (1).jpeg
 
capguncowboy

capguncowboy

Well-Known Member
#2
#2
1988 model H30 (3hp). Not all H30s have side exhausts. Side exhausts were normally reserved for edgers, tillers and other commercial equipment. Mini bike specific H30s have a rear exhaust (most of the time). That being said, you can look up that specific engine on Parts Tree and see the exhaust orientation.
 
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danford1

danford1

#3
#3
Thanks. I looked at the illustration on parts tree for the model number.
Item number 1 is the block. It only shows the carb hole (in the wrong location) and no exhaust hole which would lead me to believe it is on the other side.
After I reviewed that illustration it made me wonder exactly which engine this is. I think the pull start shroud is from a different engine.

Is there any other way to determine what engine this is besides parts tree?

Thanks
Danford1
 
capguncowboy

capguncowboy

Well-Known Member
#4
#4
sorry, had a brain fart. Yes, you're correct. That's either an HS40 or HS50 (reversed intake and exhaust). You can pull the head and measure the bore to know for sure. Removing the exhaust could tell you which as well (d-shaped exhaust port would be HS50)
 
danford1

danford1

#5
#5
I don't want to pull the head. I'd need a new gasket that I don't have and would have to buy. Same with the exhaust.
It runs well and I don't need the down time waiting for parts...

Would an H30 pull start shroud fit and H40 or H50?

Danford1
 
minikenny

minikenny

Member
#6
#6


From the spark plug wire routing that is very early 70's probably HS40. It is old enough almost would have to be original to your 400 series Cat... :)laugh: sorry Joe, I meant "Duster MX" :laugh:)

Someone just put a different shroud on it. :thumbsup: Great score.
 
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minikenny

minikenny

Member
#7
#7
danford1 said:
I don't want to pull the head. I'd need a new gasket that I don't have and would have to buy. Same with the exhaust.
It runs well and I don't need the down time waiting for parts...

Would an H30 pull start shroud fit and H40 or H50?

Danford1
Click to expand...
You wouldn't need a new gasket. The head gaskets from back then were reusable. But the easiest way to tell for sure would be to check the intake port. Round is HS40, triangle is HS50.

But I bet that is the HS40 that came on the bike. :thumbsup:
 
danford1

danford1

#8
#8
OK . Capguncowboy said remove the exhaust and look for D shaped port. Minnikenny says remove the intake. Is this a typo on someones part or are both ports D shaped on the H40?
Looks like I have to order some gaskets just to see what engine I have :)
Sooooo, does the H40 and H50 use the same exhaust and intake gasket? I need to know what to buy.
I want gaskets in hand so I can find out without loosing ride time. This is great weather for a ride.
IF I pull the head, what bore is the H30, H40 and H50?
Thanks for the help thus far. I want to mark this thread with the best answer but can't yet...
It seems to have a lot of power for 3hp. Will an H30 shroud even fit on an H50?

Danford1
 
minikenny

minikenny

Member
#9
#9
You don't need new gaskets.

It's not an H40 or an H50. It's a HS40.

That H30 shroud is installed on and will fit a HS40 or a HS50.

Intake port is round on HS40. Exhaust port is 1/2" NPT.

Intake port is triangular on HS50. Exhaust port is 3/4" NPT.

Edit: HS40 bore is 2.625", HS50 bore is 2.812".
 
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danford1

danford1

#10
#10
Thank minikenny,
Is there a number on the block somewhere I can can look for?
My exhaust is held in with 1/4-20 screws.
I'll "attempt" to pull the carb and exhaust off but if the gaskets start to rip, I'll abort the mission.
I'll see if it has 1/2 or 3/4 npt.

Thanks again. We are getting close :)

Danford1
 
danford1

danford1

#11
#11
Ok, You were right, I didn't need any gaskets. It came apart very easily.
Here are some picts of the ports and the exhaust pipe measurements.
The exhaust port has a 0.728" ID

Danford1

File_001 (4).jpeg File_003.jpeg File_004.jpeg File_006.jpeg
 
minikenny

minikenny

Member
#12
#12
HS40, very early 70's. I'd say very likely original to the bike. :thumbsup:

Too bad somebody lost the shroud. I'm guessing the recoil broke and they just switched the whole thing rather than repair it. :eek:ut:
 
danford1

danford1

#13
#13
I pulled the head and measured the bore and stroke :) No gasket will be needed either.
It is 2 5/8" bore and 1 15/16" stroke.
What bore and stroke was the HS35?
I'd like to make sure it is a HS40 and nothing else.
Thanks

Danford1
 
OND

OND

#14
#14
2.625 is pretty close to 2'' 5/8 or it was when I went to school ! :laugh:

I stand corrected as capgun pointed out Two and five eighths ! :laugh:
 
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minikenny

minikenny

Member
#17
#17
danford1 said:
I pulled the head and measured the bore and stroke :) No gasket will be needed either.
It is 2 5/8" bore and 1 15/16" stroke.
What bore and stroke was the HS35?
I'd like to make sure it is a HS40 and nothing else.
Thanks

Danford1
Click to expand...
No such thing as a HS35. And it's not a H35 either. H35 has 2 1/2" bore. When I went to school that was close to 2.500" :lol::lol:
 
markus

markus

Well-Known Member
#19
#19
danford1 said:
I pulled the head and measured the bore and stroke :) No gasket will be needed either.
It is 2 5/8" bore and 1 15/16" stroke.
What bore and stroke was the HS35?
I'd like to make sure it is a HS40 and nothing else.
Thanks

Danford1
Click to expand...
It is an HS40, it was built between late 1974 late 1976 due to the design and parts that are seen on it, That also meshes well with the bike it is sitting on, as it appears to be a late model cat bike, they used the HS40 in that configuration/color as well. that company ran out of gas in the 1975 timeframe too.
 
minikenny

minikenny

Member
#20
#20
Markus is the expert here, I'm just an amateur at this. I thought by 1975 the plug wire was routed around the back of the engine rather than the front. That's why I said early 70's.

Anyway, it is whatever year your bike is. :laugh: They didn't make Cats after the mid 70's. :thumbsup:
 
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