It was real nice this evening and my kid wanted to ride. So I got out her 1967-1969 CCS Charger, Built in S. Bend Indiana, fitted with 6" solid wheels powered by a 1970 Tecumseh HS50 rebuilt using NOS Tecumseh parts. When she lifts the throttle and then gets back on it it would just die. This is the third time we used it since I built it and it ran like a charm the first two times out. It sorta baffles me, I've never had a problem with a carb I did. If they rattled they have always worked. If it was a Holley on a car, I would be putting a shot pump or larger squirter on it. That's how it acts. But it's only when she would lift to go around the one end of the house, as soon as she would get back on it it would just die. It will fire right off and take off real strong? I used a old brake lever/kill switch combo when I built it so I thought maybe it had to do with her maybe turning or leaning the bike? So I unhooked it to be sure it wasn't some crazy problem with the switch. It wasn't. I'm going to put another carb together and put it on tonight or tomorrow evening. I just felt like talking to someone.:stuart:
My Heald Super Tryke carb ran better before putting a kit in it so I robbed a parts mower of its, sat in the rain gunked up bad gas carb and it runs better! I should stay away from carbs all together or get better kitting them! Same thing on Qjets and old Holleys, I think the gunk is all that keeps them together after years of build-up! Probably something simple on your tecumseh though, you'll figure it out! I kitted the mower carb and it runs fine, just a bad carb or not enough vat time on my deal!
Jeeeeeeez, don't just talk to be friendly... Some people throw a FIT about that... :lol: The carb Randy, I sincerely say the high speed jet needed just a little more fuel... I've seen them run great for the fisrt day or two, then want to be fine tuned again one last time.. :shrug: makes no sense I know but it happens... I WOULD SAY though... Most likely it's because the get off it then get BACK ON it, lets the throttle open right up and coughs out because there isn't QUITE enough fuel.. give it an 1/8 turn out on the high speed and try it.. That requires putting it back on and all but I'll bet she was just a little bit lean.. :shrug:
hmy: don't do that... Is it an adjustable body? Sounds like to me.. Man I will buy it from you.. don't EVER scrap something like that...
DO NOT THROW THE CARB AWAY. I've been intrigued by the various posts that talk about the carb "rattle'. Some mention a "check ball". I have studied the carb info in my old TEC manual and just took a carb apart to see what rattles. Here is what I have determined.
FACT There is no check ball; there is a reduction rod in the idle fuel transfer passage. The passage is the "tube" siamesed to the main jet "tube" that is part of the carb body.[where the adjustable jet screws in] The steel reduction rod is .094 dia. and 3/4 inches long. It fits in the .125 dia. transfer passage and reduces the volume of fuel available to the idle adjustment screw area. [It was done this way for manufacturing purposes.]
OPINION It doesn't matter if the carb rattles: it only matters that fuel flows thru the transfer passage. This can be determined by plugging [with your fingers] the idle and intermediate orifices and idle air bleed. You will need to remove the throttle plate and shaft to do this. After plugging the holes, blow compressed air into the idle adjust. screw hole. Air should come the main jet "tube". You may want to put a piece of tape over the end of the main jet "tube" to see if it blows loose. If air blows thru, carb should work.
I don't think any carb should be thrown away unless the shaft holes are badly worn or there is physical damage. We need to keep as many as possible. I'm going to try to get some parts so we can open up the idle fuel transfer passage and clean it and free the reduction rod if necessary. If I can find the parts and someone is reluctant to do theirs, they can send the carb body to me and I'll stick it in my Bridgeport and do it for them.
I'm going to keep researching this and will post what I find. If anyone wants a carb schematic to see what I'm talking about.PM me an address and I'll send you the info.
When I get all figured out, I'll figure out how to post pics and diagrams and put it all in the TEC egine sub forum.
FACT There is no check ball; there is a reduction rod in the idle fuel transfer passage. The passage is the "tube" siamesed to the main jet "tube" that is part of the carb body.[where the adjustable jet screws in] The steel reduction rod is .094 dia. and 3/4 inches long. It fits in the .125 dia. transfer passage and reduces the volume of fuel available to the idle adjustment screw area. [It was done this way for manufacturing purposes.]
OPINION It doesn't matter if the carb rattles: it only matters that fuel flows thru the transfer passage. This can be determined by plugging [with your fingers] the idle and intermediate orifices and idle air bleed. You will need to remove the throttle plate and shaft to do this. After plugging the holes, blow compressed air into the idle adjust. screw hole. Air should come the main jet "tube". You may want to put a piece of tape over the end of the main jet "tube" to see if it blows loose. If air blows thru, carb should work.
I don't think any carb should be thrown away unless the shaft holes are badly worn or there is physical damage. We need to keep as many as possible. I'm going to try to get some parts so we can open up the idle fuel transfer passage and clean it and free the reduction rod if necessary. If I can find the parts and someone is reluctant to do theirs, they can send the carb body to me and I'll stick it in my Bridgeport and do it for them.
I'm going to keep researching this and will post what I find. If anyone wants a carb schematic to see what I'm talking about.PM me an address and I'll send you the info.
When I get all figured out, I'll figure out how to post pics and diagrams and put it all in the TEC egine sub forum.
I shit you not, I did the same thing yesterday. You'll have to ask Dad. I was so excited I called him.
I always wanted to do it to see what is actually in there. After I seen the rod and knew where it rode I took a carb that would not rattle and heated the bore beside the emulation tube, it started smoking out of the idle air screw hole and then like resin literally ran out of the hole. Now it rattles freely.
If you look inside of the Idle air hole you can see the rod in there.
I also determined the big carbs with the short air screw "with the little point" do not have the rod. I cut one of them apart as-well. I have talked with some Tecumseh mechanics and they warned me that not all the carbs need to rattle. All I knew was if they did not I could not get them to work. But now I know the difference. So I'm going to put one of them together and see how it works.
What I did last night on one was drill the brass plug out and tap the rod "up", as soon as it moved it was free and I was able to turn the carb and it fell out. The tiny plug maybe hard to find so I thought about threading the hole just a few turns and bottoming out a set screw. The newer ones have a round ball pounded in the hole, so that would be an option as well.
When I mentioned scraping one I was not going to throw it out. I have a 5 gallon bucket almost full of them. I think I have around 30 +/-
On the other carb that started this thread, I could not find anything in it that could have been clogging it. The float may have been a little low so I raised that and re-assembled it. I'll see if it acts any different.
I always wanted to do it to see what is actually in there. After I seen the rod and knew where it rode I took a carb that would not rattle and heated the bore beside the emulation tube, it started smoking out of the idle air screw hole and then like resin literally ran out of the hole. Now it rattles freely.
If you look inside of the Idle air hole you can see the rod in there.
I also determined the big carbs with the short air screw "with the little point" do not have the rod. I cut one of them apart as-well. I have talked with some Tecumseh mechanics and they warned me that not all the carbs need to rattle. All I knew was if they did not I could not get them to work. But now I know the difference. So I'm going to put one of them together and see how it works.
What I did last night on one was drill the brass plug out and tap the rod "up", as soon as it moved it was free and I was able to turn the carb and it fell out. The tiny plug maybe hard to find so I thought about threading the hole just a few turns and bottoming out a set screw. The newer ones have a round ball pounded in the hole, so that would be an option as well.
When I mentioned scraping one I was not going to throw it out. I have a 5 gallon bucket almost full of them. I think I have around 30 +/-
On the other carb that started this thread, I could not find anything in it that could have been clogging it. The float may have been a little low so I raised that and re-assembled it. I'll see if it acts any different.
That makes sense, when you flip the carb "with a free rod" you can look in the hole for the screw and see it. I have read many times both here and over at
4-cyclekarting, guys will instruct folks that the carb must be up right to install the main jet. But that is not the case. What must have happened is the facts got distorted over the years.
With this known I don't think there are any bad carbs? There is one other plug that can be removed in that idle circuit. With it removed you can get to all the passages. The rod must just reduce the volume of the area? It's not like it could ride up and down in the bore. Thats what I originally thought. That it was like a metering rod that was pulled up by vacuum but thats not the case.
4-cyclekarting, guys will instruct folks that the carb must be up right to install the main jet. But that is not the case. What must have happened is the facts got distorted over the years.
With this known I don't think there are any bad carbs? There is one other plug that can be removed in that idle circuit. With it removed you can get to all the passages. The rod must just reduce the volume of the area? It's not like it could ride up and down in the bore. Thats what I originally thought. That it was like a metering rod that was pulled up by vacuum but thats not the case.
I think for manufacturing purposes they could not drill that deep with less than an 1/8 dia. drill on a production basis. For some reason the idle circuit can't handle that much volume so they put the rod in to essentially mimic a very small hole. I'm guessing the brass plug is mostly to keep the rod from falling out prior to assembly. I don't see any reason functionally the bottom needs to be sealed. I'm going to try to find a source for plugs this week.
Let me know how you make out. I thought it would be sealed because the bottom is submerged in fuel and it could suck fuel under deceleration? Maybe not, IDK.
I've seen welsh plugs as small as 3/16 I think, so that would be an option, just to bore the existing hole deep enough to accept a welsh plug. Or a disk of shim stock tapped into the hole with a drift?
The other one just runs on an angle into the bore. It's a large hole all the way through. That must be where they pick up the air.
If you could, I would like to see the schematic. randyk72 @ verizon . net
I've seen welsh plugs as small as 3/16 I think, so that would be an option, just to bore the existing hole deep enough to accept a welsh plug. Or a disk of shim stock tapped into the hole with a drift?
The other one just runs on an angle into the bore. It's a large hole all the way through. That must be where they pick up the air.
If you could, I would like to see the schematic. randyk72 @ verizon . net