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Hello, can anybody help me. I have a old Snapper 8 hp 4-cycle Tecumseh rear engine mower, the number on the motor is TVM 195, the problem I am having is it will not start on it own I have to use a little shot of starter fluid for it to start, once it starts it will run until I turn it off. I have rebuilt the carburetor it is a series 3 carburetor, I am not sure if I have the linkages connected correctly but I think I do because it runs, it has a governor and a governor override, there was nothing connected to the choke and when I look in all the manuals they show nothing connected to the choke and when I asked at the Snapper service center at Ace they said the choke works automatically with the vacuum of the motor. Once I spray the starter fluid in the breather it will start on the first pull and even if I turn it off and I then try to restart, it will restart without the starter fluid on the first pull. I have rebuilt the carburetor, put in a new spark plug, installed new fuel lines, put in a new fuel filter, put in a new air filter and changed the oil. While the motor is running I have tried to adjust the main mixture screw but I can't notice any difference I can unscrew it until the gas starts coming out and if I screw it in all the way the motor dies and when I try to adjust the idle mixture screw nothing happens. Thanks for any help.
 

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The fact that the mixture screw has little effect lead me to believe the carb. is restricted.
However:
Could be...
1. Choke not functioning
2. Bent choke plate (butterfly), not closing off venturi fully
3. Restricted main jet or feed nozzle in carb. (did you use a new main jet?)
4. Bad intake valve
5. Vacuum leak
There is no "governor override."
The choke on those engines was engaged by a tang pointing straight down from the throttle control plate bellcrank that sits above the carb. (bolts to the intake manifold). I've seen this tang get broken off more than just a few times in my day.
If the engine smokes blue when running, it could just be that the engine is worn out.
Check these things and let us know.
Paul
 

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Discussion Starter #3 (Edited)
There is no "governor override."
What !!! Then what are they talking about in the manuals and what is on the side of the motor they called a governor override lever?

GOVERNOR OVERRIDE SYSTEM FOR TVM170, 195 AND 220 ENGINES
This system will be found starting on 1985 production models, and will not retrofit onto older engines. It is designed to allow the governor to regulate the low and high speeds of the engine. The high speed is adjusted at the top screw of the override lever; to increase R.P.M. turn the screw out (counterclockwise), to decrease R.P.M. turn the screw in (clockwise). The low speed is adjusted at the bottom screw of the override lever; to increase R.P.M. turn the screw in or clockwise, to decrease R.P.M. turn the screw out or counterclockwise.
Pictures from the service manuals:



The fact that the mixture screw has little effect lead me to believe the carb. is restricted.
I rebuilt the carburetor, I don't think it is restricted in any way.

However:
Could be...
1. Choke not functioning
1. The choke may indeed not be functioning, its hard to tell if it is closing now with the air cleaner body installed and I didn't see anything attached to the choke during dis-assembly.

2. Bent choke plate (butterfly), not closing off venturi fully
2. The choke plate (shutter or butterfly) is not bent.

3. Restricted main jet or feed nozzle in carb. (did you use a new main jet?)
3. I don't think the main jet or feed nozzle is restricted, I rebuilt the carburetor: New main mixture screw, bowel nut, idle mixture screw, float, float spring, hinge pin, needle, needle clip, needle seat, bowel gasket and even new welch plugs.

4. Bad intake valve
4. I don't think so, it runs if the intake valve was bad I don't think it would run for very long.

5. Vacuum leak
5. I also installed a new carburetor gasket. I don't think there is any vacuum leaks.

The choke on those engines was engaged by a tang pointing straight down from the throttle control plate bellcrank that sits above the carb. (bolts to the intake manifold). I've seen this tang get broken off more than just a few times in my day.
I will have to check the tang on the throttle control plate.

If the engine smokes blue when running, it could just be that the engine is worn out.
The engine doesn't really smoke, I mean you can smell the exhaust and the engine runs a little rough but like I said turning the main mixture screw and idle mixture screw doesn't have much of an effect so I haven't been able to adjust it.

Check these things and let us know.
Paul
 

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So much for manuals. I don't read them much. Was asked to write 4 chapters for ICS Home Study (the old ads with Sally Struthers). Anyway, didn't know that the "governor override" had such a name. It's a play on words. It's not an truly an override. What Tecumseh did was to come out with a system to allow for a governed idle, to compensate for various OATs (outside ambient temperatures) which would compensate for cold oil and the like by controlling the idle with the governor rather than a throttle stop screw on the carburetor. That system CAN'T affect starting performance by itself unless things are bent up bad etc.

Anyway, read through your comments. Perhaps the easiest thing may be the problem. Move the throttle control to max, which should close the choke as well. Ensure the choke bell crank on top of the carburetor is twisted by the controls as far as it will go. If you can still rotate it some, even just an 1/8", the choke butterfly, i.e. shutter or i.e. plate can't do it's job and hard or no-starting will result.

Paul
 

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Discussion Starter #5
I love manuals the more information I get the better, I'm always wanting to know the details of how things go together and how they work and their part numbers and what they are named.

I haven't had an opportunity to check anything yet, but I'm guessing from your information that you posted that the reason for not starting on its own is going to be the throttle control plate tang not being inline with the choke, I couldn't see how it was lined up when I took it off I guess I need a good picture in a manual of how it lines up or some for detailed instruction in layman terms.
 

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I would have to agree with paul, there has to be some restriction in the main jet. If you open it to the point that fuel starts to leak, then then engine should be running extremely rich. Since it's not, then there must be a reason the fuel is not flowing into the nozzle.

The control bracket that attaches to the intake manifold over the top of the carburetor is adjustable. The orientation can be adjusted to allow full engagement of the choke.

A leaking valve intake or exhaust, can result in reduced compression, which can affect cold starting, so do not discount this a possible reason for a hard start issue.
 

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i have found lately that even the rebuild kits for Tecumseh have been sitting on the shelves for so long that the seals are not even that good

the one i put in the other day even had to be reamed because of the unknown trash that was in the main jet and replacement set screw that came with the bowl nut

the parts store was dumbfounded when they opened to other kits and they were stopped up this trash from manufacturing

so new are not clean all parts before you install

that is my new Mateo

that little trash cost me 3 trips to the parts house and half days work

thanks for the help

i love this place :wave:
 

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Discussion Starter #8
Engine starts now

Well I got the engine to start now without using starter fluid, thanks to Paul for pointing me in the right direction, it was the tang on the control plate not engaging the choke, I tried moving the control plate all the way in each direction but it still would not engage the choke, what I had to do was hold the choke lever closed and then adjust the control plate, now when I move the speed selector to the choke position the tang presses the choke lever and the choke shutter closes. Thanks Paul

I took the new main jet back out and everything looked good, I went ahead and cleaned it and now when I adjust the main mixture screw it has an effect on the motor. The main jet has two large holes (Fuel inlet ports) next to its bottom and one small hole (Idle fuel transfer passage) about half way up, I used a needle to make sure the small hole was clear and I used lots of carb cleaner.

It seems to be running to fast when I have the speed selector set on slow, I have tried adjusting the idle screw (low speed screw/throttle crack screw) but it doesn't seem to have any effect and I have also tried adjusting the idle mixture screw but it has no effect unless I start to remove it completely then the motor sounds like its going to die so I quickly put it back in. On the governor override I have adjusted the low speed adjustment screw and that slowed the motor down but I have unscrewed that screw almost all the way out.

Also I've noticed when I move the speed selector from slow to fast quickly the governor moves back and forth a lot for a few moments, if I move the speed selector slowly it doesn't do this. I have drove it around and cut grass with it and it doesn't seem to have any problems pulling itself or engaging the blade or cutting grass but the motor still seems to sputter a little.
 

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Well I got the engine to start now without using starter fluid, thanks to Paul for pointing me in the right direction, it was the tang on the control plate not engaging the choke, I tried moving the control plate all the way in each direction but it still would not engage the choke, what I had to do was hold the choke lever closed and then adjust the control plate, now when I move the speed selector to the choke position the tang presses the choke lever and the choke shutter closes. Thanks Paul

I took the new main jet back out and everything looked good, I went ahead and cleaned it and now when I adjust the main mixture screw it has an effect on the motor. The main jet has two large holes (Fuel inlet ports) next to its bottom and one small hole (Idle fuel transfer passage) about half way up, I used a needle to make sure the small hole was clear and I used lots of carb cleaner.

It seems to be running to fast when I have the speed selector set on slow, I have tried adjusting the idle screw (low speed screw/throttle crack screw) but it doesn't seem to have any effect and I have also tried adjusting the idle mixture screw but it has no effect unless I start to remove it completely then the motor sounds like its going to die so I quickly put it back in. On the governor override I have adjusted the low speed adjustment screw and that slowed the motor down but I have unscrewed that screw almost all the way out.

Also I've noticed when I move the speed selector from slow to fast quickly the governor moves back and forth a lot for a few moments, if I move the speed selector slowly it doesn't do this. I have drove it around and cut grass with it and it doesn't seem to have any problems pulling itself or engaging the blade or cutting grass but the motor still seems to sputter a little.
the governor moving back and forth for a few moments is normal (it does the same thing on my JD170)
 

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The throttle plate on top of the carb. has holes in it. The lever riveted to it has holes in it. When you move the throttle to full (no choke) a hole in the arm should line up with a hole in the plate. You can put a probe or pin in it at that point to keep the lever from moving, then loosen the plate mounting screws and adjust it until the tang is grazing the choke bell crank. You can usually do that setting without having to pin it. The idea is that when it's set correctly, when you come off choke to full throttle or move it up from idle to full throttle, the choke is not engaged at all. BUT, if you go back and re-do the setting (you have it working now, so why F with it?) be sure the choke closes fully. Sometimes you have to move the plate a bit to get the tang to engage properly and swing the choke bellcrank smoothly. It's not a real precise control, but it's worked for decades.

I wouldn't worry about idle too much as long as high speed is working well and you can mow. The governor spring may be twisted at one end, effectively shortening it. This would raise the idle, and the high RPM as well. The idle crack screw on that unit isn't supposed to hold the throttle open, that's the "override" arm screw's job. HOWEVER, there's NO REASON you can eliminate the "override" idle screw and use the carb. mounted crack screw. If you don't use it in cold weather, there's no real benefit from a governed idle.

The high-speed sputter may just be a slightly over-rich mixture. Try turning the mixture screw in 1/8 turn and re-test.
 
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