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RocketRod
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Joined: July 19, 2007
Posts: 641
Location: Colorado Springs, CO
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 Posted: Wed Dec 15, 2010 3:53 pm Post subject: PDSIT 32/34 -2 or -3 Carb question |
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Searched and didn't find any info on my question. On the electric choke there is a diaphragm with a slotted shaft. This shaft fits under the choke mechanical linkage. My question is what is the slot for as it does not touch any of the choke mechanical levers. Maybe I just don't understand the entire diaphragm.
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busdaddy
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Joined: February 12, 2004
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Location: Surrey B.C. Canada, but thinking of Ukraine
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| Posted: Wed Dec 15, 2010 4:13 pm Post subject: |
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If you close the choke plate completely and pull on the shaft like the diapghram would the purpose will become clear young Jedi.
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RocketRod
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Joined: July 19, 2007
Posts: 641
Location: Colorado Springs, CO
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| Posted: Wed Dec 15, 2010 10:54 pm Post subject: |
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No BD, I still don't get it. Its the choke vacuum diaphragm. Held closed by a small spring. I have another carb soaking overnight so I can do some more discovery tomorrow.
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Amskeptic
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Joined: October 18, 2002
Posts: 8568
Location: All Across The Country
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| Posted: Wed Dec 15, 2010 11:23 pm Post subject: |
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| RocketRod wrote: |
| No BD, I still don't get it. Its the choke vacuum diaphragm. Held closed by a small spring. I have another carb soaking overnight so I can do some more discovery tomorrow. |
It is called the "vacuum break diaphragm" and it has a very specific task. That cut-out in the shaft of the vacuum break diaphragm is to allow the choke full range of movement from closed to open. It is not supposed to touch anything. There is a "rolled pin" on the choke plate lever that sort of tucks into that cut-out.
The *only* time that the vacuum break does anything is right after start-up on cold mornings. The choke plate has to be closed on cold mornings during initial cranking right? But right after a successful start, the engine has to have air, now! The vacuum break diaphragm pulls that cut-out shaft down and trips *open* the choke a little bit. It's sole job is to prevent the choke from flooding out the engine just after start. It is important, it needs to work.
Colin
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RocketRod
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Joined: July 19, 2007
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Location: Colorado Springs, CO
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| Posted: Thu Dec 16, 2010 6:35 am Post subject: |
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Thanks Colin. It does move freely and now I understand its operation.
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