| Roxyghia70 |
Mon Jan 15, 2007 1:28 am |
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i want to but an engine w/dual 40 webbers in a f.i. porsche 914
i ran the engine on the bench, the 1 carb isnt sprayin at all
i gues thats the acel. pump, i dont know maybe a port is plugged
also it back fires out the exhaust when it decelerates
lastly i was jus wondering any advice you might have for this switch |
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| 66 Käfer |
Tue Jan 16, 2007 1:32 pm |
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The obvious thing on the carb not spraying is to make sure it is actually has gas in it. If it does have gas then check the injection pump mechanism to make sure it is actuating the pump and also check the diaphragm on the injection pump to make sure it isn't ripped, broken or whatever. You can check the passages by blowing some carburetor cleaner through them and determined wether it is blocked or not. Backfiring on the exhaust side isn't actually back-firing, it is actually an explosion of un-burnt gas in the exhaust.
Usually it is a combination of a rich mixture and and exhaust leak somewhere. What happens is that when you lift off the gas, some oxygen gets pulled in through the exhaust leak and mixes with the rich exhaust fumes and it ignites the mixture causing the explosions. Some cars even withouth the exhaust leak will do that particularly race motors that have a lot of overlap on their cams and big carburetors.
The 40 IDFs once tuned properly are great, especially if you are looking for some more performance. A header will give you some more flow and a centrifugal advance distributor may be neccessary as well to get the most out of them. The stock efi works great also but it can be troublesome and expensive to maintain. Part are getting hard to get for them. Don't give-up on the Webers, it may take you some time to get them right but they are worth it. Whatever you do, don't go to a single progressive...LOL |
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