I have been just removing the top on the car, I have to admit the Carter is EASY to work on....the only pain is I keep having to remove the metering rods to drop it back on so I dont bend them. I have a rebuild kit(from Standard?) on the shelf somewhere, I'll have to check how the needles are configured, I may wind up using them, depending how this next test goes... I swapped the needle/seat assemblies side to side, but kept the same floats in position, and re-adjusted the top limits... I did blow into the inlet, both floats funtion like you'd expect and are parallel at 3/16 gap....I'll probably fire it up over the next hour or so - have to run some errands first. Special Wagon - I know we've been over installing return lines on this board, I assume it's a simple as using an A/C spec fuel filter, hard lines to the tank and modifying the sending unit.... How did you do that? Do you have a photo of the finished unit? I'm hoping it never comes to that!
I finally got out there to try things out after swapping needle/seat assms from side to side... sure enough, now the drivers side is flooding out. Go figure, I would have sworn that both were just fine, and they held air, etc..I'll double check the float levels, but the floats stayed on the same side, with very little adjustment.
Rhett, I don't know where your coming up with this 3/16ths. measurement. Is the carb. a stock AFB??? Is it an Edelbrock replacement???? How are you adjusting the float level???? Turn carb. top up-side-down with the top gasket installed. Measure the float level with the appropriate sized drill bit. The measurement is from the end of the float farthest away from the seat. Edelbrocks are 7/16ths. NOT 3/16ths. Stock level is more than 3/16ths. more like 3/8ths. Follow the instructions that came with the rebuild kit. No need for the heat spacer. Have you blocked the exhaust crossover under the carb??? Not at the heads, but the exhaust holes under the carb. in the manifold. Did you shake the float when you had it out to see if there was any fuel in it????
I took the needle and seat out of the rebuild kit I had (Hygrade, not Standard) - they had the rubber tips. Swapped them in, they seem to seat with no leaks. I took a good hard look at the brass tipped ones I took out, they were brand new - I'll be damned if I can find anything wrong with them. Go figure.
Tom - The carb is a stock AFB, a 3921 I got the 3/16s measurement from the shop manual, I did use a drill bit at the far end of the float. At 3/16, it does put the float fairly level, I left a hair more clearance to be safe. 3/8 looks like it would keep the float fairly low all the time... I did shake the floats, between both my carbs I had two that had fuel in them, using the remaing two on this carb now. I had the heat risers blocked at one time, but the car developed a flat spot off idle, with the heat back in it dissapeared. it sure did sound cool with them blocked though...
This shows that it was the needle/seat assm. BTW, the Hygrade is from Standard, and is the same kit i used.
Rhett, blocking the holes under the carb. DOES NOT eliminate the heat in the manifold, which is, as you found out, causes a hesitation. Blocking the holes under the carb. is NOT detrimental. Sorry Doc, this is one of the things I don't agree with you on. The heat under the manifold is NOT being eliminated!!!! Heat will still be under the manifold just not as close to the carb. I have done it so many times I can't remember how many. Like on my Riv. I don't have a heat riser either, just the holes under the carb. blocked. Also the aluminum AFB will heat up faster than a Rochester with a cast iron base plate. Also Rhett, just to let you know NEW BRASS floats are available. Tom T.
Actually, Tom,, it aint a big deal....I know that you are real sharp and will eventually figure it out....:laugh: :laugh: Yep,, it is as Tom says,,, the heat goes both places....and you can run the carb cool without running the manifold cold.... I have seen people install a fuel pressure regulator just before it goes into the carb.... but you have to be carefull with regulators because some of them just restrict the flow instead of lowering the pressure.... I had a carter on a 312 ford engine that i did that with....and it cured it ....
I appreciate both points of view, and hope to get to a point where I can try both and decide what this car likes best.. however.... It's still doing it. It had been raining, and I never got the chance to get the car up to operating temp until last night. I let the car idle for 15 minutes (just to the point where you cant leave your hand on the valve cover for any length of time - not burning hot, but hot..) and shut it off. The car has run good the whole time, not loading up. I wait approximately 5 minutes, and fuel begins to drip out of the drivers side venturi again. There is no evidence of fuel boiling, and the intake is hot, but you can still leave you hand on it. Strangest of all, the dripping continues after you remove the fuel line, so line pressure isnt a factor. That leaves me with float level and associated bowl level. Not knowing the internal path of the fuel, my assumption is : to leak out the venturi, the fuel would have to travel through the jet first, right? As the jet is at the bottom of the bowl, there would have to be some kind of either siphon or pressure effect. Pressure is out as the vents are clear.....so it's a siphon thing unless the fuel could take another, higher path to the venturi.. I set these floats to a hair lower than 3/16 at top travel, and confirmed thats the spec in the shop manual. Both floats are dry, and have full travel. Tom - you mentioned a 3/8 top measurement... although it seems low to me, can you please confirm? Also as this is now truly a carb problem, should I bother to move this thread to the Carter/Mixing Shop thread? I hate to waste real estate for those who arent interested.. Thanks again -
The venturi outlet is within 1/4" of the top of the carb base....so fuel level must be rising above that. You could test the theory by removing the carb top and filling the bowl.... then watch where the level is when it stops dripping. You did say fuel pressure at the carb drops after engine is shut off. Fuel is either going into the carb, or back thru the fuel pump. I still believe your bowl is filling up after shutoff.... which means it's getting past the needle/seat, or the carb top has a leak in the fuel passage. 1966 shop manual measures the float level differently. 1-15/32" to the bottom of the float.
Hi Rhett, You said earlier that when you switched the needle/seat assembly to the other side it then switched which side was dripping. Does this not show us anything?????? Not an expert, just trying to help out if i can. If you've got enough help on this i won't post again. Cheers, Gary
I'll take all the advice and help I can get (so dont be bashful), but maybe I wasnt clear... When the problem jumped sides, I was pretty sure I had it nailed down to the needle/seat assm, so I switched both sides out with new needles and seats from a unused Hygrade kit I had.. reset float levels and thought I was good, until I had a chance to get the car up to operating temp and found it was still doing it, but strangely again on the drivers side (primary), the side with the issue AFTER I switched needles and seats from side to side. So I'm back to float level - I'm sure I've got them set correctly to Factory specs (3/16 as measured at the far end of the float) Tom suggests 3/16 may be too high, and to check the Hygrade instructions, which I havent had the chance to do yet...but if it was too high I'd figure both sides to flood...
OK - full disclosure. I was taking the float level measurement from the 65 shop manual (3/16) However, after Tom weighed in I checked the Hygrade rebuild instructions - they specify 15/64ths. Then I actually checked the Gransport shop manual supplement and it shows 6/32nds....ooops So I reset the float levels to 15/64ths, with a little extra for good measure and ran it up to temp.... And it still does it. It took about ten minutes, maybe 15 but it begins to drip from the drivers venturi, pulled the carb top and sure enough the drivers side bowl level is higher - see attached photo arrgghh.
I guess the next step is to swap the new needle/seat assemblies back from side to side, and see if the problem follows BTW, the Gran Sport supplement was 7/32, not 6/32..
Check the floats again to make sure. If they seem OK submerge them in a container of gasoline. Put a weight on them to hold them down in the position they would be installed in. Let them stay in the bowl for a few hours & check again.
Thanks Tom - I swapped needle/seat assemblies from side to side again, and ran it up to temp. I gave it 20 minutes and no leak. I'm a little too sceptical to declare victory, but sometimes, especially with any kind of leak, it just takes a massive amount of ****ing around until it's right. Maybe I've gotten lucky. Thanks again to all
Although it sounds like I'm a touch too late and you've already got it fixed, would it help to try a different carb and see what happens?
