Tecumseh HS40 cuts out when I try to accelerate

markus

markus

Well-Known Member
#41
#41
massacre said:
If you set the dial to zero, .035” before zero is .065”, right?
That is how the dial reads on my dial indicator anyways

Like for instance if you were setting something at .010” before 0, the dial will read .090”
Is this helping? lol
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yea, your right that may show that way depending on your indicator, I'm a little spoiled as I have been using the Actual tecumseh indicator which the dial face reads reversed so it show the actual measurement as the dial goes down (counterclockwise). I havent used anything else for the last 5 or 6 years and use it for other things as well so I am very used to it and how it reads.
 
massacre

massacre

#42
#42
markus said:
yea, your right that may show that way depending on your indicator, I'm a little spoiled as I have been using the Actual tecumseh indicator which the dial face reads reversed so it show the actual measurement as the dial goes down (counterclockwise). I havent used anything else for the last 5 or 6 years and use it for other things as well so I am very used to it and how it reads.
Click to expand...
Ahh OK
Makes total sense now lmao
On a Tec specific dial indicator with the numbers going the other way it would read as you say.

Here’s my dial indicator



Been using it for years to check the specs on v8 camshafts.
 
Rupp_It_Up

Rupp_It_Up

#43
#43
As a last resort I decided to take apart the good running Rupp HS40 (left) and compare it to the non-running motor (right) and noticed the exhaust valve was different on the non-running motor. Since this was a non-running motor when I bought the bike a few years ago, I'm wondering if someone tried modifying it and that's why it never ran or did Tecumseh use different style exhaust valves?
72 Rupp Motors - Exhaust Valves.jpg
 
massacre

massacre

#44
#44
Tecumseh did use different style exhaust valves. They both look stock to me. I have motors with both styles and they look identical to yours
 
delray

delray

Well-Known Member
#45
#45
Rupp_It_Up said:
As a last resort I decided to take apart the good running Rupp HS40 (left) and compare it to the non-running motor (right) and noticed the exhaust valve was different on the non-running motor. Since this was a non-running motor when I bought the bike a few years ago, I'm wondering if someone tried modifying it and that's why it never ran or did Tecumseh use different style exhaust valves?
View attachment 249053
Click to expand...
now that you got it apart. it wouldn't hurt to lap the valves and make sure they are seated correct and lifter to valve clearance too. assuming that is the motor your having all the problems with? i have had couple stock motors that came apart and had that style valve.
 
Rupp_It_Up

Rupp_It_Up

#47
#47
I checked valve clearance and the intake/exhaust valves are within the .004" - .010" spec.

The non-running motor has a slight oil leak at the crank seal so, before I replace the seal, I might as well take off the cover and check the timing. It looks correct when I compare the timing to the good motor, but ya never know!

I'll also lap the valves as delray suggested.

Thanks again for everyone's suggestions.
 
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