flightofphx Samba Member
Joined: September 11, 2017 Posts: 114 Location: AZ
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Posted: Sat Apr 01, 2023 7:25 pm Post subject: Chasing an air leak - need suggestions |
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I have a 2276 with stage II heads, FK8 cam, and dual 48 IDA carbs (clones). I have been chasing an air leak on 1 -2 and I am almost out of ideas.
Short history, when I bought it the total timing was set at 40 and it was jetted with 70 idles and running rich. I put 60 idle jets in it and brought the timing back down to 30 total and started to tune the carbs. I noticed the pump jets were dripping and I replaced the O rings and they still dripped. I could only get them to not drip by reaching under and holding the trottle shaft. I pulled the 48 IDA (Spanish) off and I am on a waiting list to have them refurbed. In the meantime, I bought some recommended Chinese 48 clones off ebay. (I know, I know, hit or miss). My current issue is an air leak on 1 and 2. I can cover the stacks with my hands and notice a slight decrease in RPM, but the engine keeps running choked. I pulled the carb and manifold and replaced gaskets and made sure the flanges were flat (slight filing). I replaced the carb gasket and the top and bottom plates are flat. I restarted and immediately after starting the car cold, I could choke and kill the engine with my hand over 1 or 2 velocity stacks. I thought it was fixed. But, as soon as the engine heated up to operating temp, I can no longer choke with my hand over either stack. I sprayed starter fluid around the carb halves, and both end of the manifold and do not hear a change in RPM. Also, with the snail gauge on I can adjust the idle speed and it will move the meter up or down. If I turn in the idle mixture screws all the way in AFTER it is at operating temp, the engine will keep running. If I leave them in and let it cool all the way down it will not start unless I turn them back out a turn or more.
If I cover 3 or 4, it dies right away. Tomorrow, I am going to swap the carbs and test. In the meantime, I am wondering if anyone has ideas? |
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Mikedrevguy Samba Member
Joined: October 15, 2008 Posts: 2240 Location: Medford, OR
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Posted: Sun Apr 02, 2023 7:52 am Post subject: Re: Chasing an air leak - need suggestions |
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Where’s fuel pressure set?
Could swap carbs left to right and see that the problem follows the carb. _________________ 74 1303 (RevBug): plan for German Look
76 914 with 2260
79 VW Iltis
69 Bwajaja
"The wise speak because they have something to say; while the foolish speak because they have to say something." Plato
Illigitimi non-Carborundum!! |
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