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fuel pressure question

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healeyboz

healeyboz

Jedi Knight
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Would having different size lines in the system cause a problem with richness?

I have 5/16 line from the tank to the pump to a gauge and then step down to a 1/4 line to fit the su.

I am trying to locate a good regulator to put in line before the the carbs but it looks like I am going to have to step down to 1/4 after the regulator. Will this cause a problem?

I am thinking about what it is like with a smaller nozzle on a garden hose.

Thoughts?
 
IMO, Pressure should be the same anywhere after the pump. Size will only affect amount of fluid through the pipe, slower through the larger, faster through the smaller.
 
Yes that's right--won't affect the pressure. Flow rates are so low in these cars that anything related to them doesn't really matter. Make sure the pressure out of the fuel pump is OK--more than about 3 PSI could be a problem. I had all kinds of problems with float valves not shutting off until I installed a regulator and got it down to 2 PSI.
 
I'm rereading your post and while I know nothing - and I mean nothing about carbs, it strikes me that pressure might be an overflow/ flooding issue but that richness is more about finesse than flow. Assuming your flow needles are shutting off correctly and the floats are correctly set, I'd be looking further down the line.

Choke? Is it on/ shutting off properly?
vacuum - any leaks? / is air getting in anywhere - spray WD40 around manifolds joints etc and listen for sound change
Needle Adjustment?
Piston/ Piston oil?

might be more helpful
 
Carbon loading up in the exhaust and fuel in oil. The carbs have been rebuilt by Hap. I am pretty sure it is a fuel pressure issue--just trying to figure out how to fix it for good. I had a cheapo regulator on it and it seemed to help with the fuel in the oil thing. But I would get a horrible vapor lock. Took the regulator out and she ran again. :frown:
 
Barry sounds like yo are way too rich, I build alot of carbs, I know we talked Saturday, forgive me for not remembering about what, I recovering form a nasty stomach virus, and a little drugged up right now. At first we used the #3 needle with the jet at .070" down the bridge, and if I remember correctly, then switched you back to thew AN needle which is stock for the 1275. Both these needle and jet settings are pretty basic and seem to have worked many times with outher cars/customer/engines, not to say your car doesn't want something different, but if you're now running the AN needle with the jet about .070" down, that is the factory setting, if at that point you are still too rich, my thought would be that the timing is retarded which for sure would cause a rich condition, where is your timing set at, at idle and at 3000 rpms?
 
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