11-26-2020, 06:51 PM
Chapter 69
So this one modified HL-66 carburetor is actually a reality. I went ahead and assembled it with new diaphragms and needle/seat. My first thought was just staying with the nylon needle and rubber seat. It seemed to work decent enough on all of the chainsaw carburetors. When I was at Gassets shop, Mr Grimes gave me a quick tutorial on how to set up the inlet control lever and check the needle to make sure it holds pressure. He did not tell me how much pressure or any reliable way to test. Just apply some light air pressure and check for any leakage around the needle.
I kept testing all of the carburetors that were still partially assembled with the internal parts. Not one of them gave me any idea of repetitive numbers so there is no baseline to go by. I was somewhat frustrated by the time dad walked in the garage. He asked what I has having trouble with. After some explanation, he was surprised I was so in depth with how these carburetors actually functioned.
After some trial and error, dad managed to rig up some tubing with a pointed rubber tip. It was attached to a small regulator and pressure gauge tied into the compressor. He finally worked things out to reliably test the pressure at which the needle maintains before opening and then bleeding off. If I opened the control valve on regulator very slowly, the pressure on gauge would start to climb. Most of the chainsaw carburetors that would still hold pressure started bleeding off around six pounds. Really anything and everything on either side of that pressure.
Now I was more interested in the HL-93. It was in good condition. After setting it up on the pressure tester, I managed to get it consistently bleeding at 7-8 pounds. After comparing the different springs that are used under the inlet control levers, I was satisfied these readings were close to accurate.
All of these carburetors used the same short soft spring that was bronze looking in color. After checking the parts list, I noticed some of the newer model carburetors had changed over to a stiffer spring. It was longer, silver in color and had more coils. With this spring the pressure held right at 10 pounds.
After thinking it over, I made the decision to go with the HL-115 parts. Another trip to Gasset secured these tiny pieces needed to go forward with the first test carburetor. I showed Mr Grimes what had been put together for testing these carburetors. He thought it was a really neat looking gadget and interesting. But didnt know what benefit it have with rebuilding these carburetors.
I asked Mr Grimes if there was any difference in performance if the pressures varied up and down too much. He had absolutely no clue and never seen any information in print on making these adjustments for any engine. He changed these parts only if the carburetor was not working correctly. If that didnt fix anything then changed out with a new carburetor.
Once again, I am looking at things that may not make any difference. So far I have not found any information in repair manuals either. The tuning pages covering Tillotson carburetors did not disclose any details. Only if carburetor was not working properly, then clean well and use the correct major repair kit.
For my own curiosity, I decided to start testing the carburetors we are running. Keep records on all of the different readings between them. Then maybe a pattern would show itself eventually. If I could get a general setting to shoot for, then might make these carburetors work more consistently. Or do the Frank Price way, and just throw the carburetor in a box if it doesnt work the first time around the track.
So now I have an one off super custom extremely modified untested carburetor, that looks really cool, but no information on how to set it up and no clue what to start the needles at. That is not a solid way to start out for a test day. Or is it? Well at least the karts are running well. Well enough to use as a baseline to make changes for comparisons with each one. That is somewhat helpful. I am so ready to make another trip out to the track.
But first it would be a really good idea to try out this carburetor on an engine in the garage. Make sure it will start up and if I am lucky it might actually idle. Then see if the engine will accelerate without laying over or loading up. That would be a good first test to make sure if what I have been working on will even make it to the track without being a complete failure.
Right now this sure would be a good time to make a few trips down the street again. But I know better than trying that stunt again. It would save a bunch of time to find out if the carburetor does or does not work at all. But maybe if I try it out on an engine, and load it down with the brake pedal depressed, could give me a good enough idea of what to expect. If I was still a clueless 12 year old kid, then the street would be my first choice without even considering the consequences. It just makes sense. But I cant go down that road, well the street anymore. I am grown up now at 13. I should start acting like an adult since I am nearly one.
So this one modified HL-66 carburetor is actually a reality. I went ahead and assembled it with new diaphragms and needle/seat. My first thought was just staying with the nylon needle and rubber seat. It seemed to work decent enough on all of the chainsaw carburetors. When I was at Gassets shop, Mr Grimes gave me a quick tutorial on how to set up the inlet control lever and check the needle to make sure it holds pressure. He did not tell me how much pressure or any reliable way to test. Just apply some light air pressure and check for any leakage around the needle.
I kept testing all of the carburetors that were still partially assembled with the internal parts. Not one of them gave me any idea of repetitive numbers so there is no baseline to go by. I was somewhat frustrated by the time dad walked in the garage. He asked what I has having trouble with. After some explanation, he was surprised I was so in depth with how these carburetors actually functioned.
After some trial and error, dad managed to rig up some tubing with a pointed rubber tip. It was attached to a small regulator and pressure gauge tied into the compressor. He finally worked things out to reliably test the pressure at which the needle maintains before opening and then bleeding off. If I opened the control valve on regulator very slowly, the pressure on gauge would start to climb. Most of the chainsaw carburetors that would still hold pressure started bleeding off around six pounds. Really anything and everything on either side of that pressure.
Now I was more interested in the HL-93. It was in good condition. After setting it up on the pressure tester, I managed to get it consistently bleeding at 7-8 pounds. After comparing the different springs that are used under the inlet control levers, I was satisfied these readings were close to accurate.
All of these carburetors used the same short soft spring that was bronze looking in color. After checking the parts list, I noticed some of the newer model carburetors had changed over to a stiffer spring. It was longer, silver in color and had more coils. With this spring the pressure held right at 10 pounds.
After thinking it over, I made the decision to go with the HL-115 parts. Another trip to Gasset secured these tiny pieces needed to go forward with the first test carburetor. I showed Mr Grimes what had been put together for testing these carburetors. He thought it was a really neat looking gadget and interesting. But didnt know what benefit it have with rebuilding these carburetors.
I asked Mr Grimes if there was any difference in performance if the pressures varied up and down too much. He had absolutely no clue and never seen any information in print on making these adjustments for any engine. He changed these parts only if the carburetor was not working correctly. If that didnt fix anything then changed out with a new carburetor.
Once again, I am looking at things that may not make any difference. So far I have not found any information in repair manuals either. The tuning pages covering Tillotson carburetors did not disclose any details. Only if carburetor was not working properly, then clean well and use the correct major repair kit.
For my own curiosity, I decided to start testing the carburetors we are running. Keep records on all of the different readings between them. Then maybe a pattern would show itself eventually. If I could get a general setting to shoot for, then might make these carburetors work more consistently. Or do the Frank Price way, and just throw the carburetor in a box if it doesnt work the first time around the track.
So now I have an one off super custom extremely modified untested carburetor, that looks really cool, but no information on how to set it up and no clue what to start the needles at. That is not a solid way to start out for a test day. Or is it? Well at least the karts are running well. Well enough to use as a baseline to make changes for comparisons with each one. That is somewhat helpful. I am so ready to make another trip out to the track.
But first it would be a really good idea to try out this carburetor on an engine in the garage. Make sure it will start up and if I am lucky it might actually idle. Then see if the engine will accelerate without laying over or loading up. That would be a good first test to make sure if what I have been working on will even make it to the track without being a complete failure.
Right now this sure would be a good time to make a few trips down the street again. But I know better than trying that stunt again. It would save a bunch of time to find out if the carburetor does or does not work at all. But maybe if I try it out on an engine, and load it down with the brake pedal depressed, could give me a good enough idea of what to expect. If I was still a clueless 12 year old kid, then the street would be my first choice without even considering the consequences. It just makes sense. But I cant go down that road, well the street anymore. I am grown up now at 13. I should start acting like an adult since I am nearly one.