I've been having a lot of trouble with a single carb 94 set up. Plugs keep fouling even with idle circuits only one quarter turn open. These are only about five minutes old. I've checked and rechecked best I know how. Even to the extent of putting a degree wheel on the crank, and setting a total time to 34° per manufacturers instructions. I've had about four different power valves installed. But none less than a 7.5. I've even rebuilt the float and needle, installed a pressure gauge in the fuel line to ***ure that no more than 2 1/2 to 3 pounds at any time are present It just seems that I cant build vacuum or good idle to make what I believe is the power valve dumping; hold. There's not much of a manifold here to check for leaks and I can't see a reason why the engine wouldn't make at least 10. I'm running out of ideas even to the extent of having a new Holley setting on the floor. I just can't bring myself to put it in Posted using the Full Custom H.A.M.B. App!
Float set too high? While it's running look down the throat of the carb & see if it's dripping fuel from the venturi. One sign the float might be set too high. Also what size jets are you running?
Also take the float and submerse in gas (NOT WATER) to check if there is a pinhole leak. The little rulers that come with the rebuild kits are useless. Should be set (floats) lower than they say. Jets should be 51's. Rarely get too far from those. PV should be specific to that carb New Holley ones don't work. Also sometimes the little PV nylon washers don't seal right. And some of the reproduction PVs have an improper radius for these things. Your PV should have flat mounting shoulders and a small narrow tip. 7.5 I find sometimes is too much. 5.5 Might be better. Get them from ****ster here on the hamb. There's about 90 hours worth of reading on this stuff in the links in my signature below..
PV can't dump anything until well above idle, as it acts as an extra part of main circuit...so if this prob is at idle, you need to examine seal of PV to body for a simple leak caused by wrong PV and/or PV gasket...the number on the valve means nothing until engine is way off idle. Simplest start is to fill carb fully (run engine or carefully pour gas into bowl via a vent), dry any spill, then just set it down and see if gas comes out at bottom. When you pull PV examine the bottom of the body...you fill see the PV hole is surrounded by a flat ring that is the gasket seal surface. Check it for dings and scratches, of course. Next, gasket...it should match the above ring. On PV, wrong ones (unmodified 4160 type) will have a sloping shallow conical surface where you want sealing to happen, no good obviously, and a flat sealing ring about equivalent in ID to the OD of your gasket. If that stuff looks OK, test it directly while body is off base by filling bowl again and watching that area. Next check float level (and leakage, as above), always set to lowest spec or even a bit lower, meaning biggest number in USA Ford measurement. Also look directly as noted above at venturi area nozzle bars, as the only way main circuit can feed at idle is high fuel level. Nozzle bars have two tiny vents, one each into idle fuel and main circuit, make sure they are open. What Model carb is this...model is on left side of bowl on most 94's.
Another whacko thought...be sure you have the little check ball that lives under the accel pump and the needle that closes off pump feed at squirter. I am not sure if that stuff could feed except at high rpm, but I've never studied that, and it sure won't do any good if the checks are gone... Another source of trouble while you are in there, but likely not this trouble, is the inlet needle. The rubber tip ones tend to hang closed, don't know if problem is the rubber itself or if there is a burr on seat of current inlet br***, but I cure this by placing viton needle carefully in the trash bin, taking the original steel needle and giving it a few taps with a light hammer against its seat. Another random thought...be sure the rather similar inlet needle and pump check needle are in their proper homes. I don't think I've ever checked to see if they can be incorrectly placed, but you are apparently on your first 94 and maybe that is possible.
I'll agree with the power valve seal comments. I've had similar issues in the past, and both times it was due to leaking fuel either from power valve being blown or from power valve seal being incorrect. Good luck!
Be careful with the red power valve gaskets, I have seen them split and separate in the middle. It looks good until you take it off.
Thanks for the help thus far... I've been posting all over trying to find a bit. I have read a bunch of the material here. FLOATS- I think mine are in good order. I did use the measuring square, and feel like I did correct one of the initial problems with one of the tabs. Dropping it a bit more is an easy fix. Needle and seat are new, as well as fuel levels in the bowl..being just above the power valve when I remove the cover. There is no lack of fuel(staring from the top-down), but it would be hard to tell what circuit is truly being activated. JETS- I suspect are just over .05". I can find no markings. however I was able to measure a welding tip file that fit inside with that measurement. I will be replacing them shortly with parts I have on order from V Speed. PV- I have experienced with one of the PV's diaphragm being and issue, but have since found no fuel being leaks directly into the throttle plates. I cant get it to idle at all... so I have to open up the throttle plates to in effect 'lean it out', to where i can get outside the ****pit. I suppose it could be bad idle circuits, but when I was cleaning them; function of idle needles seemed appropriate. ?Possibly? throttle plate positioning ???
Not sure on the model. I believe its a reproduction unit from carpenters. Im not near it right now, but has a logo opposite the bowl.
Well... Not so much luck today. Took off the 94; and replaced with holley 350. Same effect... Won't idle, and begs for more 'air'... Manifold is drowning in fuel. Did a valve adjustment as well. I just can't tell what's going on.... Maybe it's time to pull timing cover, but the damn thing just runs so good down the road it's hard to believe something is a tooth off ???!? Posted using the Full Custom H.A.M.B. App!
Journal entry... 23 damn days since I thought I would try to smooth the idle. Both holleys have been on and off today... No luck. Did a compression test. 120, 135, 135, 150. Bit of a head scratcher on the end. ???!!!? Posted using the Full Custom H.A.M.B. App!
The problem seems to follow the carbs. Both have the same problems. This would indicate the problem is not carb related. Not sure what fuel pressure is correct for your modern carb, but it is probably a lot higher than for the 94. 2 to 3 pounds is max for the 94 and possibly a little high. Suggest you try a different fuel pressure gage. Also, you might set up a gravity feed fuel supply with a small can and see if it solves the problems.Your posts indicate you have the experience to safely set up a gravity feed system. We had a similar problem on the start up of a rebuild. Fuel pressure on an out-of-the-box pump was over 12 pounds. Another bit of info from you would be helpful. Did it run OK before you started you carb adjustment project, or is this a new setup? What are you running for a fuel pump? Keep the feedback coming. It's how we learn. Thanks and good luck.
Been on the phone all day with Holley. Fuel pressure was 'their' concern as well with the newer carb... and I can easily alter it with the 'dial a pressure' regulator. Bowl levels have checked out all day. The car didnt run all that great before... I never noticed that previous owner failed to plug some holes in the manifold. Which I now presume was to lean it out... and make it sell!#@!$! Its a mechnical fuel pump, and a brand new Moon glycerin filled gauge.
Lots of recent mechanical pumps seem to be coming through with 7 pound springs...fuel pressure is one of the few things non-carb related. Seems almost off the chart here, though. How about temporarily eliminating the whole damn supply system as a test?? Hook up a temporary Moon tank/lawnmower tank on top of your radiator rods with direct gravity feed to the 94 and see what happens. This is getting deeply mysterious, but a gravity feed test should tell us whether we need a new pump or a shaman to settle this. Another slightly outside the box thing to check...if you can keep it running a bit, can you feel any serious pulsing holding your hand (should be your least favorite hand, you never know...) over the carb throat?
I may be trying the temp tank soon. I have held my hand over the 94 quite a bit... and dont recall a pulsing, but it does pull very hard, when you get close to 'choking' it. Ill post a pick from my phone next showing the amount of movement I need to open the throttle plates to then get it to run.
I guess it's not a good of a picture as I thought it was.. but it's at least 5/32 large It equates to about 1100 RPM before decent flooding idle Posted using the Full Custom H.A.M.B. App!
It's been the same kind of the effect thus far. still drowning in herself about half a turn out on both idle circuits and two turns in on the air mixture planting it firmly in the transition circuit Posted using the Full Custom H.A.M.B. App!
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