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#21
07-13-2022, 10:45 PM
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I have used JB Weld on many Carb main bodies over the years.
You really do not need the power valve cavity to even be there. Just seal that cavity up and post up the secondary jetting numbers you have in the secondary metering block. If they are the right size for a carb without a power valve (Power valve block) the you are good to go. Normally w/o the power valve go up 6 jet sizes. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#22
07-13-2022, 11:39 PM
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Looks like there is a check ball in the base plate, JB Weld that too?
Has 78 jets in primary and 88s in secondary, try 84s in secondaries instead? QUOTE=Tom Vaught;6356632]I have used JB Weld on many Carb main bodies over the years. You really do not need the power valve cavity to even be there. Just seal that cavity up and post up the secondary jetting numbers you have in the secondary metering block. If they are the right size for a carb without a power valve (Power valve block) the you are good to go. Normally w/o the power valve go up 6 jet sizes. Tom V.[/QUOTE] |
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#23
07-14-2022, 09:20 AM
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I think that hole is actually the factory drilled passage to provide vacuum for the power valve. The casting was probably a bit off on this carb .That passage should exit the bottom of the main body and line up with the passage in the baseplate with the check ball . If so nothing really needs to be done .
Glenn |
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#24
07-14-2022, 09:27 AM
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This carb looks like a 80497 950HP vacuum secondary . I can't tell from the pictures but I believe that carb has the idle feed restrictions in the upper location. If so moving them to the lower location will probably help a lot with your idle issue .
Glenn |
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#25
07-14-2022, 09:35 AM
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Not true, in my opinion, Glenn, sorry. The center section (main body) is damaged.
The check ball in the base plate will be pulled open when the engine is running. It is a anti-backfire valve. It seals under a high pressure spike from the intake manifold. The center section of the carb is now open to the power valve cavity. I would say that at one time the guy was trying to make a boosted carb where a drilled hole in the carb stud pressurized the center section of the carb. The center section is now open to the power valve cavity. And then the boost pressure OPENS a Reversed Power Valve Spring to add fuel under boost conditions on the secondary side. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#26
07-14-2022, 10:12 AM
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Tom , Of course I could be wrong but the more I look at the picture the more I am convinced it is the drill marks from the factory passage and yes that vacuum circuit/passage would contain the anti backfire check ball .
Glenn |
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#27
07-14-2022, 11:11 AM
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Look at post #17 again. If the accelerator pump feed hole were at the top (rotated 90 degrees), a long slot would be at the 9:00
position and a smaller slot would be at the 4:00 position. A drill make makes a circular pattern. In post #17 you can clearly see a rectangular slot cut into the metal and another smaller slot on the opposite side. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#28
07-14-2022, 01:27 PM
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I see the rectangular slot in 17 but I am talking about the gouge beside it . That looks like it was made by a drill coming up from the bottom of the main body to my old eyes.
Also , That would mean that when the op sprayed clean into it , the spray came out the hole in the bottom of the main body that lines up with the check ball and that is why Op asked if the check ball should be JB welded in post 22 . If it came out someplace else then I guess my speculations are wrong . Glenn |
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#29
07-14-2022, 02:39 PM
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Late to Party
How far is the primary idle mixture screws backed out or opened up?
Too far on front and then opening rears will just make things richer. Four corner idle is a balance game. I've had them here that 1/4 turn, from bottomed out, on all four corners, is what it took for a clean idle. If the hole in the power valve pocket goes to the check ball in the base plate... It's fine. Just made that way. I'd put it back together and try leaning out the front to see if the rears work. Clay |
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#30
07-14-2022, 02:43 PM
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My secondary power valve is plugged, could fuel get into that well in the main body causing me to lose secondary idle screw response? Also reposting pics here. Not sure I mentioned its a vacuum secondary and you are correct list 80497.
Quote:
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#31
07-14-2022, 02:45 PM
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Primary was opened to show the .040 window.
Thanks |
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#32
07-14-2022, 03:27 PM
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X72GPX , when you sprayed carb cleaner into the gash what passage did the spray exit from in the bottom of the main body ?
Glenn |
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#33
07-14-2022, 03:44 PM
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Hi Glenn, apologies, I am Damian, here is the action shot, it seems to line up with the check ball on the base plate.
Quote:
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#34
07-14-2022, 09:02 PM
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Damian, I believe this passage is normal and you should follow Clay's suggestion to put it back together and see how it works. But before you do can you tell us where the idle feed restrictions are located on the metering blocks ?
Glenn |
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#35
07-14-2022, 09:38 PM
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The original post was referring to the Secondary Idle screws.
Could you post a picture of the bottom of the base plate so I can see the secondary transfer slots and the idle discharge holes? Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#36
07-15-2022, 08:14 AM
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Here is a picture of the base plate, and one with the gasket.
Quote:
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#37
07-15-2022, 09:05 AM
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In order to see the transfer slot and the idle discharge holes in the baseplate the throttle blades need to be open fully and the pictures taken from the bottom.
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#38
07-15-2022, 09:21 AM
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Ok here they are, does this look right?
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#39
07-16-2022, 02:32 PM
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If i put it back together without finding whats wrong, how would I get a different outcome?
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#40
07-16-2022, 05:30 PM
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When you put a light in one of the Transfer Slot holes where the gasket would normally be, is the tiny hole below the transfer slot lit up?
Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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