Posted: Sun Feb 13, 2011 10:38 am Post subject: YS Carb Rebuild
Hi Everyone. Still at it . My engine started and ran till the gas ran out that I poured down the carb. It seems that the carb is not pumping any fuel into the engine. I removed the line to the carb and cleaned a very clogged filter. I reconnected the line and tried pumping the accelerater,but no sign of fuel. I then removed the top of the carb and there was fuel in the float chamber. This tells me it is time for a rebuild. Does any one have a diagram for a ys carb ? The kit I purchased does not have a breakdown sheet included.This would be my first attempt to rebuild a carb.
On the YS carb., It doesn't do any good to pump the accelerator pedal to get gas in the throat nor actuating the butterfly on the carburetor because it doesn't have an accelerator pump in the carburetor. _________________ Tropical Veteran
35th Inf. Reg. "CACTI" 4th I.D. VN
Amateur Radio K5XOM
Posted: Mon Feb 14, 2011 10:07 am Post subject: YS Carb Rebuild
Can't thank you enough for your input and technical assistance. It sure gives one confidence to see that we can tap in to so much knowledge and most of all the willingness to help strangers with the same hobby. Again special thanks to all.
You said the filter was plugged up. This means you have trash in your fuel system. You will need to resolve that issue first. It may be that enough of that trash has entered your carb and plugged up the small passageways in it.
If this is true then fix the trash issue first which most likely is corrosion in the tank. Then make sure the pump is delivering fuel at at least 2.5 PSI. Then clean out the carb and blow the passageways to make sure they are not plugged. Then reassemble the carb and try running it.
In the illustration below from the carb rebuild manual I have corrected the positions of the two springs that operate the diaphragms. Be sure you use this diagram or the one from the M38/M38A1 parts manual.
As mentioned above, unlike the civvy carbs the accelerator pump you are used to seeing squirt gas into the throat of the carb on the civvy carbs will not on the M38/M38A1 carbs. They use a vacuum operated accelerator pump and they also use a vacuum operated metering rod. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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