Carb/idle question

[t-bird88]

Now if Kay had fuel injection I could fix this in a minute, but carbs are a strange beast with me that I can never get set right. I have rebuilt this carb once last fall (so don't ask me about particulates about the carb, I really don't remember) and cleaned a lot of rust out of the fuel bowl area and changed out the jets. This is a TSX 241 B carb if that helps any, to me they all look the same. So here is the deal:

New motor starts right up, full throttle 1800 RPM and "POPS" through the exhaust. The needle on my tach kind of jumps around a little bit. The kicker is if I pull out and hold on the choke just a bit that the motor smooths out and increases the RPM up to 1900. If I turn the idle adjusting needle any where from the seated position the tractor starts popping and running rough. If I pull out on the the choke a little bit more it smooths out. It really does not matter where the power adjusting needle is set at because the further out it is turned the worse that it runs with the exception of being seated, where it dies.

It also will not idle below 1100 RPM without popping through the exhaust and dieing. Once it gets to about 1150 I can turn the idle adjusting needle out and it smooths out just a bit, but it still will not idle down, even when I change the setting on the idle speed adjustment screw.

I do know that if the choke has to be pulled out there is not enough fuel getting to the jets, but even with a fuel pump hooked up to the fuel line (I know that the 2N's were gravity feed, just trying to figure out where the restriction is) I still have to have the choke pulled back and held just about 1/3 to 1/2 way closed. And as far as I know, all of the holes/orifices/passages/screens are clear. What have I missed?

Jim B :roll: .

 

[NOXJohn]

Most of the time you will find that you have an ignition problem when your tractor acts like that. Check the spark, points and plugs.

 

[FatTony]

Had a very similar problem.

Cleaned my electrical connections and put in fresh points and plugs. Now no more need for the choke, even to start. Cheap fix & takes no more than an hour to complete.
:lol:

 

[t-bird88]

It has a new set of points, condenser, plugs and wires. I just rebuilt the carb and reset the float bowl level, blew out ALL the orifices, jets, and even replaced a perfectly good throttle shaft, and the best that I can get is 1600 RPM full throttle and 700 RPM low throttle. I personally think that the carb is just wore out and needs to be replaced.

I am beginning to hate carbs!

Jim B :x .

 

[JMOR]

(quoted from post at 19:05:28 11/01/09) It has a new set of points, condenser, plugs and wires. I just rebuilt the carb and reset the float bowl level, blew out ALL the orifices, jets, and even replaced a perfectly good throttle shaft, and the best that I can get is 1600 RPM full throttle and 700 RPM low throttle. I personally think that the carb is just wore out and needs to be replaced.

I am beginning to hate carbs!

Jim B :x .

Very little inside to wear. Throttle shaft/bushings. You could toss in a choke shaft, but it likely isn't your problem for more than one reason. Nothing else does much moving to wear.

You may have found every passage, but I would guess that many times some of the 12 or 13 passages in the little carbs are missed, not to mention the 3 very small holes in side of nozzle. Got to get everyone.

 

[t-bird88]

I think that it has to be the carb, because when I first got it; the thing ran just fine...other than not having enough compression. But I had to rebuild the carb due to crap that I found in the tank/sediment bowl/and carb itself. I found rust out the wazoo and one of the jets was clogged up. Now that it has been rebuilt, that tractor will not run like it did when I first got it.

I don't know, i may have to figure something else out. Port injection is looking pretty good at this point.

Jim B :roll: .

 

[jdchet]

(quoted from post at 21:21:51 11/01/09) I think that it has to be the carb, because when I first got it; the thing ran just fine...other than not having enough compression. But I had to rebuild the carb due to crap that I found in the tank/sediment bowl/and carb itself. I found rust out the wazoo and one of the jets was clogged up. Now that it has been rebuilt, that tractor will not run like it did when I first got it.

I don't know, i may have to figure something else out. Port injection is looking pretty good at this point.

Jim B :roll: .

I changed alot of fuel system parts to compensate for a bad(coil)ignition system!

JD

 

[t-bird88]

I am really having a hard time accepting that the electrical system will prevent the engine from revving low and high. I changed out the coil, condenser, points and ballast resister just last fall. The tractor sat in my shop since then and did not run until yesterday. Could something like the coil or the condenser go bad without power to it for almost a year? I mean I know that weirder things have happened, but at this point I am grasping at straws and wearing on my last nerve.

Jim B :roll: .

 

[JMOR]

(quoted from post at 01:06:12 11/02/09) I am really having a hard time accepting that the electrical system will prevent the engine from revving low and high. I changed out the coil, condenser, points and ballast resister just last fall. The tractor sat in my shop since then and did not run until yesterday. Could something like the coil or the condenser go bad without power to it for almost a year? I mean I know that weirder things have happened, but at this point I am grasping at straws and wearing on my last nerve.

Jim B :roll: .

o you have a timing light? Timing is not your problem, but it would allow you to see the rhythm of the spark....you will pick out missing pulses visually.

 

[DanH01]

I"d hold off on the carb replacement for a minute. First thing I"d do is a search in the archives for correct fuel flow and running rich. For fuel flow you remove the plug on the bottom of the carb and time how long it takes to fill a small container. This will tell ya if you have any fuel restrictions. If you had alot of rust you might not of got it all the first time. I think it was 3 or 4 minutes to fill 1 or 2 cups. Something like that.

If you have to pull the choke to get her to run (in other words enriching the fuel mixture) then your spark plugs don"t need as much spark to ignite the fuel. Which means that you"ve got weak spark. So the components the other posters told ya about need to be checked. I"d start with the Plugs to make sure you"re getting a good blue spark and then work back to the ignition switch (which is usually the cause of the weak spark). Check you wire connections make sure they are clean and tight. And check your ground off of the battery. I'd ground that off of one of the dash mounting bolts.

Do those searches there's no telling how many times these very issues have been posted and answered by the Gurus around here.

 

[jdchet]

Just a thought on this.........Maybe you have a intake manifold leak causing a low vacuum situation? Might explain the popping deal. Also make sure your governor is operating properly.

JD :?

 

[t-bird88]

Okay here is an update that may help to figure some things out.

I took some time (actually a lot of time) and read some of the previous posts and found one that Bruce (VA) posted repeatedly like here:

http://ytforums.ytmag.com/viewtopic.php?t=546304&highlight=coil

Now I took and measured the resistance at the resistor and I got 1.6 Ohms, I then measured the coil and got 1.4 Ohms. Now correct me if my math is wrong (which it seldom is) Current = 14.5v/(1.6=1.4) = 4.83 Amps at the coil. Now if I understand Bruce correctly this is too much current flowing through the coil. So I found a spare ballast resistor and measured it and got 2.1 Ohms resistance. Running this through Ohms Law my Current = 14.5/(1.4 + 1.6 + 2.1) = 2.8 Amps! This should (again according to my math) be under the 3.0 Ohm limit for the 6 volt coil.

So my question is is can I just run the two ballast resistors in series with each other in the same circuit to the coil and not fry anything? And could this be the problem that has been keeping Kay from revving up and down to the limits???? And also is it too late for the coil or will I need to replace it with a new one (6 volt variety)????

Jim B :roll: .

 

[t-bird88]

And to let you guys know the voltage at the coil now, it was 6.8 volts now it is 2.92 volts. Is this within the proper parameters for a 12V system with a 6V coil???

Jim B :roll: .

 

[JMOR]

(quoted from post at 18:04:55 11/02/09)
And to let you guys know the voltage at the coil now, it was 6.8 volts now it is 2.92 volts. Is this within the proper parameters for a 12V system with a 6V coil???

Jim B :roll: .

4.8amps is closer to right than 2.8amps, so I say put it back the way it was, as you have a weaker spark now than you had before. What you changed will not help your running situation at all. Yes, I think Bruce likes 4, but 4.8 will not be a problem.