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20 hp v-twin only runs on one cylinder

#1

B

Beel61

Hi, I have a 46" Murray Tractor with a 20hp v-twin........down on power.....checked the plugs and one was hot and one was cold......switched plugs...same side not firing.......pulled plug on that side.....have good spark....started it with that plug out and it appears to have good compression, or at least some.......So, I have spark....have compression......why would it only get fuel to one cylinder ? .any ideas ??? Thanks


#2

Fish

Fish

Pull the valve covers off and take a peek.


#3

reynoldston

reynoldston

Beel61 said:
Hi, I have a 46" Murray Tractor with a 20hp v-twin........down on power.....checked the plugs and one was hot and one was cold......switched plugs...same side not firing.......pulled plug on that side.....have good spark....started it with that plug out and it appears to have good compression, or at least some.......So, I have spark....have compression......why would it only get fuel to one cylinder ? .any ideas ??? Thanks
Click to expand...

Good spark and good compression. Just how did to test for these two things? You did test for spark under compression and checked compression with a leak down test, right?? I agree you might want to pull the valve cover and take a peek if you can get to it easy. There just are no short cuts. The only reason you would get lean fuel to one cylinder would be a vacuum leak.


#4

B

Beel61

Did some research and found this engine has 2 carbs, so I am guessing...one carb must be plugged up.....????


#5

Fish

Fish

Just take off the valve covers. The gasket usually stays on the cover, so it will cost you nothing, and will save you a bunch of money.


#6

Fish

Fish

4 bolts on each cover......... Might take you 15 minutes..........


#7

Fish

Fish

No wait, I can sell you the carb!!!! Which one do you want???


#8

reynoldston

reynoldston

Beel61 said:
Did some research and found this engine has 2 carbs, so I am guessing...one carb must be plugged up.....????
Click to expand...

Yes that is very possible. Two intake manifolds also ? Check the needle valve in that carburetor.


#9

Fish

Fish

Lol, yes!!!! One of the rare Murrayghinis, racing mowers!!!!!!!! Not quite as fast as the MTD Testerosa!!!!!!

Well, to be any help at all, he should put up some model numbers!!!!


#10

briggs

briggs

please post model number of engine i got to see this beast


#11

B

Beel61

It is a Tecumseh Enduro VT 20hp...............is it that hard to believe it has 2 carbs ???


#12

Fish

Fish

Well who would farkin know?????

So you are going to finally drop another crumb/clue???? Thanks for that, we all enjoy jumping through these stupid hoops!!!!!! Can you at least give us up a spec number,
or should we be thrilled that you allowed us this much info?????


#13

Fish

Fish

Naw, do not waste any of your "research" here.....


#14

briggs

briggs

we need the model number of the engine to help u out :confused2:


#15

reynoldston

reynoldston

Beel61 said:
It is a Tecumseh Enduro VT 20hp...............is it that hard to believe it has 2 carbs ???
Click to expand...

Your mower and you know what it has I don't. Dose it have two intake manifolds? Now did you check the needle valve in the second carburetor? I don't always worry about model numbers, because I think about pass jobs I have done.


#16

Carscw

Carscw

Beel61 said:
It is a Tecumseh Enduro VT 20hp...............is it that hard to believe it has 2 carbs ???
Click to expand...


You have to excuse the people on here. If they do not have one then no one does.

Yes this engine does have 2 carbs.

I have a 27hp with the duel carbs.


#17

reynoldston

reynoldston

I never question the two carburetors because I didn't know. I also work on motorcycles and its very common to have more then one carb. Some time back I worked on a older Gold Wing and it had four carburetors. It s big pain getting them adjusted all the same so it runs right. It would have to be the same for a lawn mower. Never come across more then one carburetor on a mower yet, but not saying I wouldn't. I hope they do away with carburetors all together and go to fuel injection because I think its a lot better system and the engine just runs a lot better. Just think about it carburetors go back to the early 1900's and its time to move on.


#18

Carscw

Carscw

reynoldston said:
I never question the two carburetors because I didn't know. I also work on motorcycles and its very common to have more then one carb. Some time back I worked on a older Gold Wing and it had four carburetors. It s big pain getting them adjusted all the same so it runs right. It would have to be the same for a lawn mower. Never come across more then one carburetor on a mower yet, but not saying I wouldn't. I hope they do away with carburetors all together and go to fuel injection because I think its a lot better system and the engine just runs a lot better. Just think about it carburetors go back to the early 1900's and its time to move on.
Click to expand...


I agree fuel Injection engines run much better. Untill you have to buy parts.


#19

reynoldston

reynoldston

Carscw said:
I agree fuel Injection engines run much better. Untill you have to buy parts.
Click to expand...

The biggest problem I find with fuel injection is plugged fuel filters or some injection cleaner, other then that they seem trouble free.


#20

reynoldston

reynoldston

reynoldston said:
The biggest problem I find with fuel injection is plugged fuel filters or some injection cleaner, other then that they seem trouble free.
Click to expand...

I forgot about the fuel pump not putting out enough pressure to open the injectors.


#21

B

Beel61

briggs said:
we need the model number of the engine to help u out :confused2:
Click to expand...


It is Model TVT691.................took the valve cover off, everything looks to be functioning properly........took the carb off the cylinder that is not firing......looks very clean......

There is a few wires going to the float bowl, I am assuming some type of safety shut off ??


#22

Carscw

Carscw

Beel61 said:
It is Model TVT691.................took the valve cover off, everything looks to be functioning properly........took the carb off the cylinder that is not firing......looks very clean...... There is a few wires going to the float bowl, I am assuming some type of safety shut off ??
Click to expand...

The wires go to the anti backfire solinoid
One wire is ground the other is 12volts.

Make shire power is getting to it when the keys is in the run spot.


#23

B

Beel61

Carscw said:
The wires go to the anti backfire solinoid
One wire is ground the other is 12volts.

Make shire power is getting to it when the keys is in the run spot.
Click to expand...

just curious how an anti-backfire solenoid works ?? from the float bowl ??

The parts book calls this a fuel shut off solenoid.....I am going to switch the bowls and see if this is the problem


#24

M

motoman

Bee, when you looked at the valve system did you look at the guide positions-if they both stuck out above the head the same distance?


#25

Carscw

Carscw

Beel61 said:
just curious how an anti-backfire solenoid works ?? from the float bowl ?? The parts book calls this a fuel shut off solenoid.....I am going to switch the bowls and see if this is the problem
Click to expand...

They are both the same thing and are there for the same reason.

It cuts fuel off from leaving the bowl and going into the engine.

A backfire happens when you shut the key off and the engine makes a few turns shutting done letting gas into the cyl.


#26

Fish

Fish

Carscw said:
They are both the same thing and are there for the same reason.

It cuts fuel off from leaving the bowl and going into the engine.

A backfire happens when you shut the key off and the engine makes a few turns shutting done letting gas into the cyl.
Click to expand...

More precisely, letting gas get into the muffler...... The newer/quieter muffler have a lot more red hot baffles in them which ignite the excess gas fumes after shutting down. That is why the older engines did not have the solenoid.


#27

Carscw

Carscw

Fish said:
More precisely, letting gas get into the muffler...... The newer/quieter muffler have a lot more red hot baffles in them which ignite the excess gas fumes after shutting down. That is why the older engines did not have the solenoid.
Click to expand...

Thank you that is a much better explanation.


#28

Rokon

Rokon

Don't know if you found your answer but...

These engines have two coils. If you find that one coil pack is dead, you had better replace the other as well because it will fail muy pronto!!


#29

B

bertsmobile1

Beel61 said:
just curious how an anti-backfire solenoid works ?? from the float bowl ??

The parts book calls this a fuel shut off solenoid.....I am going to switch the bowls and see if this is the problem
Click to expand...

And like the after burners in our cars which we call "catalytic converters" insted of "afterburners" which is what they really are just in case Joe Public starts to wonder why they are paying good money for fuel that ends being burned after it has left their engine.
The anti- backfire valve is actually to comply with idiot California EPA total emission regulations .
Because the stop switch stops the spark but the engine continues to rotate for 5 or 6 revolutions and your engine will pump out 5 or 6 cylinder full of air fuel mix which will of course will cause all life on the planet to immediately cease to exist.


#30

B

Beel61

Beel61 said:
It is Model TVT691.................took the valve cover off, everything looks to be functioning properly........took the carb off the cylinder that is not firing......looks very clean......

There is a few wires going to the float bowl, I am assuming some type of safety shut off ??
Click to expand...

Ok, it's spring, back to working on this thing......the Engine Model # is.....TVT691 600401A.........


#31

B

Beel61

Beel61 said:
Ok, it's spring, back to working on this thing......the Engine Model # is.....TVT691 600401A.........
Click to expand...

Does anyone know if I can replace these float bowls with ones that do not have this anti-backfire thing on them ??


#32

reynoldston

reynoldston

Beel61 said:
Does anyone know if I can replace these float bowls with ones that do not have this anti-backfire thing on them ??
Click to expand...

Just cut the plunger off the solenoid.


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