Carb Rebuild YS - missing discharge check ball and weight.

1950 - 1952, M38, questions, discussions, regarding anything related to the M38.
JeepdaddyRC
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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by JeepdaddyRC » Fri Jan 20, 2023 3:22 pm

Scoutpilot, the vacuum reading was 18.5 psi with a slight fluttering of the needle.
The range of the needle flutter was about 0.5 psi (0.25 psi in each direction).
Sound like an unsuccessful carb rebuild to you?
42 GPW #91366, recovered blue drab registration 20200841, unit markings 104-415-I HQ-21 (Timberwolves)
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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by Scoutpilot » Fri Jan 20, 2023 3:30 pm

18.5 Hg (inches of mercury) is not bad. The slight flutter may indicate a lean mixture. Balancing the Idle Stop Screw (vacuum) on the throttle lever with the Idle mixture screw (fuel flow) is very important. Watching the vacuum gauge, turn the Idle Stop Screw out until the vacuum is at its highest. Then adjust the mixture screw to set the idle RPM. I like 650-700.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

JeepdaddyRC
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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by JeepdaddyRC » Sat Jan 21, 2023 1:46 pm

Unfortunately, idle stop and mixture screw adjustments did not improve performance.
This M38 remains hard to start, hard to keep running, and the off-idle bog remains.
Perhaps a passage is blocked or my rebuild fell short.
This YS637S is coming to you Scoutpilot.
Curious to see what you find.
42 GPW #91366, recovered blue drab registration 20200841, unit markings 104-415-I HQ-21 (Timberwolves)
CJs (x 4)

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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by Scoutpilot » Sat Jan 21, 2023 3:19 pm

Roger that.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5

70th Division
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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by 70th Division » Sun Jan 22, 2023 6:16 am

JeepdaddyRC wrote:
Sat Jan 21, 2023 1:46 pm
Unfortunately, idle stop and mixture screw adjustments did not improve performance.
This M38 remains hard to start, hard to keep running, and the off-idle bog remains.
Perhaps a passage is blocked or my rebuild fell short.
This YS637S is coming to you Scoutpilot.
Curious to see what you find.
Great decision !!

You can't beat Scout Pilot's skill set and quality control methods in his rebuilds !
I sent old and some frozen carbs to him, and they came back like factory fresh.

He also rebuilt my fuel-vacuum pump assembly as well for my M38-A1.


Best Regards,
Ray
Last edited by 70th Division on Sun Jan 22, 2023 6:25 am, edited 1 time in total.

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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by 70th Division » Sun Jan 22, 2023 6:19 am

Scoutpilot wrote:
Sat Jan 21, 2023 3:19 pm
Roger that.
Scoutpilot,

I will be getting in touch with you soon, as I have some more carbs to send your way :D

Best Regards,
Ray

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Scoutpilot
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Re: Carb Rebuild YS - missing discharge check ball and weight.

Post by Scoutpilot » Sun Jan 22, 2023 10:23 am

Copy that.
'70-'71 'A' Batt., 377th FA, 101AB
(Slicks and LOH's)(Col's LOH Pilot)
'71-72 CHARLIE TROOP,
16TH AIR CAV, 1ST AVN BDE (AEROSCOUTS)
LOW LEVEL HELL.
'46 CJ2A
'47 CJ2A
'48 CJ2A
'48 B1PW126
'69 CJ5


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