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| | | | Joined: Oct 2007 Posts: 388 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 388 | My engine now idles fine and starts fine after considerably amount to trial and error and setting time. I checked the vacuum pressure close the vacuum diaphram and it showed healthy ~20+ in when I gave throttle. But no throttle I saw the distributor got sucked to do some vacuum advance. Will that happen only on load like engage transmission or distributor should get advanced by vacuum as I start giving throttle. The reason I ask this is I get some pops thro carb and there is some afterfires in exhaust. Just wanted to confirm before I buy a new vacuum diaphram.
Thanks in advance
Ganesh | | | | | Joined: Jul 2001 Posts: 3,887 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Jul 2001 Posts: 3,887 | if the vacuum advance moves the dist when you touch the gas in neutral it's fine, not a bad diaphragm, a check of that is disconnecting and reconnecting the line should make a just noticeable difference in idle speed - if you have good vacuum there it's doing it's job, the vacuum holds it correctly and loss of vacuum on opening the throttle causes the movement ... the other part of the advance that might cause a problem would be the spring tension on it affecting the centrifugal advance, but might be worth checking the timing again, or even adjusting it slightly by ear
Bill | | | | | Joined: Oct 2007 Posts: 388 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 388 | Bill
Little I knew now I think got confused more, what I wanted to know was if the distributor was supposed to rotate with vacuum on giving more gas, Mine doesnot rotate either in idle nor when I try to give more gas so I was confused if it rotates only on load or it doesnot rotate at all. I am getting pops and afterfires at midrange rpms.
Thanks for your quick reply
Ganesh | | | | | Joined: May 2005 Posts: 487 'Bolter | | 'Bolter Joined: May 2005 Posts: 487 | I have a 235 in a 55.1 3100. It has a Rochester model B carb. The vacuum signal to the distributor is ported. It supplies little or no vacuum at idle. At off-idle there is vacuum supplied to the distributor. The visual result is that you can see the distributor rotate as you open the throttle slightly.
regards,
Leon | | | | | Joined: Oct 2007 Posts: 388 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 388 | Thanks Leon that is what I wanted to know because I keep giving gas and I dont see my distributor rotating.
Ganesh | | | | | Joined: Jul 2001 Posts: 3,887 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Jul 2001 Posts: 3,887 | sorry to confuse you, wasn't clear just what you were saying about movement, so the first thing I mentioned was what counts, "if the vacuum advance moves the dist when you touch the gas in neutral it's fine" it doesn't move when the engine is running at a steady idle OR at a steady higher rpm
Bill | | | | | Joined: Oct 2007 Posts: 388 Shop Shark | | Shop Shark Joined: Oct 2007 Posts: 388 | Thanks Bill, I ordered a new vacuum diaphram lets see how that works
Ganesh | | | | | Joined: Mar 2008 Posts: 374 'Bolter | | 'Bolter Joined: Mar 2008 Posts: 374 | I'm having the same issue on my 235. Found out over the weekend. I hope to take the VA on my 'extra' 216's distributor to resolve. | | |
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