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Re: Backfire and Hesitation
Posted: Mon Nov 03, 2025 11:58 am
by wesk
Not with today's copyright laws! People need to understand that outdated or obsolete parts and data must always be handled carefully and manuals reviewed to see dates of last revisions and determine age and reliability BEFORE turning the wrench.
Re: Backfire and Hesitation
Posted: Wed Nov 12, 2025 2:22 pm
by jake138
wesk wrote: Sat Oct 25, 2025 9:17 pm
Common error on carb assembly. Usually the two springs that fit in the two diaphragms will fit on either side of the carb however they are definately not the same length springs and many people mix them up on final assembly. Another common error is placing either spring on the wrong side of the diaphragm. For the M38's YS637S carb the Army's Carb manual TM 9-1826A dtd 1952 in it's assembly diagram Fig. 60 at page 114 shows the spring on the wrong side of one diaphragm which is very misleading. It is the spring item BB that is on the wrong side of the diaphragm.
Quoting Wes' response here simply to record for anyone who needs it in the future, an excerpt from TM 9-1826A is located in the Downloads section as an article titled "Y-S Carburetor Description, Adjustment, Parts, Cleaning, and Troubleshooting" which includes the figures, as well as modern color pictures at the end that show the two springs I believe Wes is reference, please correct me if I'm wrong Wes.
It should be accessible via the following link:
Y-S Carburetor Description, Adjustment, Parts, Cleaning, and Troubleshooting
Re: Backfire and Hesitation
Posted: Wed Nov 12, 2025 11:39 pm
by wesk
The new YS637S carb repair download is nice. However it has the uncorrected Figure 60 showing the fuel metering rod spring on the wrong side of the diaphragm.
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