Tecumseh Questions
 

You said it has lots of blow-by. So, with the hose connected that was
going into the carb. That blow-by is not air, it spent combustion gases
with no oxygen. So, removing that from the intake air flow would change
the mixture and that in turn could cause it to stall. That's a plausible
possibility.

Yeah that's the only thing that makes sense unless there is some passage from that connector to the intake end of the carb but I doubt that's the case.. BUT the countervailing argument is that the carb is not adjustable so it's not like it was adjusted with substantial blow-by taken into account.

I actually don't know if blow-by is excessive since I've not compared to others. As a single cylinder engine I know with the volume behind the single piston undergoing constant and considerable change I figure there will be a lot of movement in and out of the breather. I don't know if there is a one-way valve that causes only crankcase output to go to the carb or if it breathes back in that way as well. That would give it the benefit of filtered air.

I have to say, having grown up on one Tecumseh-powered mower after another, I miss adjustable carbs. In fact I'm surprised they work at all since no two engines or carbs are precisely the same so whatever mixture is built into the fixed carb cannot be as optimum as adjusting for the best.

IDK. Does the governor move at all in response to load?

No, not seeing any movement. AND the kicker is that IIRC the throttle should go to wide open when the engine is stopped. It does not. Just stays against the minimum stop.

It does bog down a little in heavier grass but not as much as I would have expected. While I have not measured the speed, I've got the limit screw for min throttle set for a more or less normal sound when it's above concrete with no load. Maybe a bit on the fast side but if so, not by much.

Tecumseh Questions
 

On Wednesday, May 23, 2018 at 12:23:53 PM UTC-4, Steve wrote:
You said it has lots of blow-by. So, with the hose connected that was
going into the carb. That blow-by is not air, it spent combustion gases
with no oxygen. So, removing that from the intake air flow would change
the mixture and that in turn could cause it to stall. That's a plausible
possibility.

Yeah that's the only thing that makes sense unless there is some passage from that connector to the intake end of the carb but I doubt that's the case. BUT the countervailing argument is that the carb is not adjustable so it's not like it was adjusted with substantial blow-by taken into account.

I actually don't know if blow-by is excessive since I've not compared to others. As a single cylinder engine I know with the volume behind the single piston undergoing constant and considerable change I figure there will be a lot of movement in and out of the breather. I don't know if there is a one-way valve that causes only crankcase output to go to the carb or if it breathes back in that way as well. That would give it the benefit of filtered air.

I have to say, having grown up on one Tecumseh-powered mower after another, I miss adjustable carbs. In fact I'm surprised they work at all since no two engines or carbs are precisely the same so whatever mixture is built into the fixed carb cannot be as optimum as adjusting for the best.


I agree. I just put a new carb on a leaf blower that never ran right from when it was new. It ran better on half choke. With the new one, it runs better and with choke off. Turns out the problem that lead me to buy the new carb wasn't the car though. It was carbon on the piston ring, causing it to jamb up, instead of springing out to seal. With that fixed and the new carb it's better than new.

I think you can buy adjusting tools for most carbs, just can't do it the old easy way. And I'll bet that running it on half choke is what contributed to the carbon build-up.




IDK. Does the governor move at all in response to load?

No, not seeing any movement. AND the kicker is that IIRC the throttle should go to wide open when the engine is stopped. It does not. Just stays against the minimum stop.



Have you looked at the online websites that sell parts? They have diagrams that show how it's put together and you can probably figure out how the governor works and how to check or inspect it.




It does bog down a little in heavier grass but not as much as I would have expected. While I have not measured the speed, I've got the limit screw for min throttle set for a more or less normal sound when it's above concrete with no load. Maybe a bit on the fast side but if so, not by much.

Tecumseh Questions
 

On 5/23/2018 9:23 AM, Steve wrote:


IDK. Does the governor move at all in response to load?

No, not seeing any movement. AND the kicker is that IIRC the throttle should go to wide open when the engine is stopped. It does not. Just stays against the minimum stop.

Does the governor move with the throttle? If you move one does the other
move with it?

I got a chipper from my father that never seemed to rev up right. It
turned out the governor-throttle connecting rod was in the wrong hole in
the throttle, so it did not move correctly. I re-positioned it, and the
thing worked great.

Tecumseh Questions
 

I agree. I just put a new carb on a leaf blower that never ran right from when it was new. It ran better on half choke. With the new one, it runs better and with choke off. Turns out the problem that lead me to buy the new carb wasn't the car though. It was carbon on the piston ring, causing it to jamb up, instead of springing out to seal. With that fixed and the new carb it's better than new.

I think you can buy adjusting tools for most carbs, just can't do it the old easy way. And I'll bet that running it on half choke is what contributed to the carbon build-up.

I would disagree with that last part. If it ran better on half choke it means there was some clogging in the carb and the choking is what was necessary to deliver the proper mix. Your part choke was not making it too rich where that might cause carbon build-up; it was delivering exactly the right mix.

Have you looked at the online websites that sell parts? They have diagrams that show how it's put together and you can probably figure out how the governor works and how to check or inspect it.

I know enough to know that on the typical Tecumseh the governor is actually a little flyweight thing deep in the engine and that's what moves the shaft that has the lever that is just behind the air cleaner, which links to the carb. It is not something you can get to (that I am aware of) except if totally dismantling the engine. Which may be the final fate of this engine.. The final bit of entertainment!

Tecumseh Questions
 

Does the governor move with the throttle? If you move one does the other
move with it?

The governor itself is deep inside the engine but the lever on the outside (just behind the air cleaner) is connected with a bent wire rod to the throttle valve. Yes, if I move one the other naturally moves. But there is no motion on its own. There is also a second wire rod which parallels the first and connects to a spring which then connects to a tab that is held by one of the carb to intake tube bolts. One bends the tab to adjust the run speed.

Previously, Tec carbs had an upper plate with a lever to adjust between tortoise and hare speed and the back end of that lever attached to the aforementioned spring. It's been dumbed down since then. But the intake tube casting still has two uprights that used to hold that upper plate. Just no longer drilled and tapped.

Tecumseh Questions
 

On Friday, May 25, 2018 at 9:11:40 AM UTC-4, Steve wrote:
Does the governor move with the throttle? If you move one does the other
move with it?

The governor itself is deep inside the engine but the lever on the outside (just behind the air cleaner) is connected with a bent wire rod to the throttle valve. Yes, if I move one the other naturally moves. But there is no motion on its own.


Then I guess there is your problem with lack of power. If it doesn't
move at all, I'm surprised it doesn't stall when it encounters some
moderate grass.




There is also a second wire rod which parallels the first and connects to a spring which then connects to a tab that is held by one of the carb to intake tube bolts. One bends the tab to adjust the run speed.

Previously, Tec carbs had an upper plate with a lever to adjust between tortoise and hare speed and the back end of that lever attached to the aforementioned spring. It's been dumbed down since then. But the intake tube casting still has two uprights that used to hold that upper plate. Just no longer drilled and tapped.