Vented Cap
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Is the fuel tank cap on the 55 Hash vented? Before I put the fuel tank sending unit on the tank, the tank was vented by the hole where the sending unit top should have been. Now I think the tank is pressurizing and causing the car to sit and flood while the fuel pump pressure drains off or the bowl drains. I can't remember ever seeing a carb dribble fuel down the throat when a car was off. Something's not right in Yucaipa ToTo.
Harry
Harry
0
Comments
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All the old cars gotta get some air in the tank somehow or you create a vacum, There should be no pressure in tank as there is no return line ---DRIBBL_DRIBBLE, sounds like you have a carb float or needle and seat problem.0
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Well, the Stant catalog says that it is vented.0
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I don't know, if I had a needle and seat problem then it would mean the tank is under pressure to push fuel into the carb and create a dribble. The tank isn't under pressure as far as I can tell as releasing the cap doesn't alleviate the problem. So if the carb isn't under pressure what is open to let fuel dribble down the throat? I have never seen this happen before without pressure being involved. I guess this could have been happening all the time and is why if I touched the throttle when the car is warm it would flood. Maybe I never looked with the aircleaners off before? Still, something isn't right.
Harry0 -
No Harry, your tank can not be pressureized as there is no return line, it is likely a carb problem, if the float needle and seat is bad and don't shut off , {or a leaky float, that sometimes happens, shake it to see if it has gas in it} the carb bowl will be over full and will drip, that is one cause and the first I would check as it is the most commen, and yes it could also be your other problem as when you open the throttle you put even more fuel to the engine, the idle screw may be adjusted to compensate now and you will have to reset it when you fix the drip.0
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If the float valve were leaking though wouldn't the screen chamber above the bowl drain? On both carbs they stay full of gas until the bowls eventually drain and let the float drop. I thought maybe my floats were too high but they measure correctly to the seam on the float. I can set them to shut off sooner but I'm afraid that will exacerbate the problem of not enough fuel on the top end. I think the floats are set at 9/16 now and I could set them to 5/8. This is very perplexing and to make matters worse I don't get home until after dark so I only have weekends to work on it now, I don't want to drop any more parts into the grass. I guess I'll reset the floats and put the carb back together. It's funny though that many of these problems didn't show up until I cleaned the tank and replumbed the fuel lines. It's possible the filter was straining all the time and restricting my flow all along.
Harry0 -
Never say never, I have seen it too many times. Whilst watching the thing dribble, put your ear close to the cap and loosen it. If there is pressure it will poof. I wholly agree that there should be a negatrive presure if it is not vented and fuel is removed....never say never.:)0
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psss, run down to your local auto part purveyor and pick up a fuel pressure regulator. Set it on 3-3.5 lbs and retry. Reading your post, you might be blowing fuel past the needle and seat whiole it's running.0
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The only way the tank could be pressurizing is from heat from the exhaust pipe that runs directly under the tank. Other wise I could be pulling a vacuum in the tank but then the carb wouldn't be pressurized because once the tank started to cool it would draw the fuel back into the tank. I am racking my brain with options all day long, I have a tendency to obscess with problems. I can't let them go until I get an answer. I really don't think there is any pressure on from the tank. Something in the carb has to be staying open to let the fuel drain down the throat, but the chambers over the bowl are now draining as fast as the gas is going down the throat. I would guess the fuel pump may be pushing gas past the valve when it is running but when the pump turns off no more pressure so why does the fuel keep running?
Harry0 -
HARRY GOTTA ASK THIS, do the carbs COMPLETELY drain, are empty when you take the top cover off? That would put things in a differant perspective than a dribble problem and a differant cause to look for. As for setting the float, is the seam the referance point for your carb? I thought the w-1 carbs were set at about 1/2 inch clearance at the freeend of the float, between the top of the float and the cover ? Forget the pressure thing and look elsewhere when you stop the engine the pump stops and does not put out any pressure, everything goes into neutral,there is no pressure in the tank,not possable at any time without a return line. The tank cap must be vented or vacume would build up pulling back on the pumps efforts and the pump would not draw any fuel. Remember the start at one end and follow to the other end thing? It works0
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Nope, they don't drain completely as far as I know, I haven't waited long enough to see that happen at least, these are the 968 S models of the W-1 carbs, the instructions call for 9/16 from the lip of the bowl to the solder seam around the float.
Harry0 -
OK, getting up to speed a bit now, How much is left in them when all the dripping stops ? Is it enough to run the car ? Without actually seeing it ,it is hard to say if your float is set wrong. I think what I would try is resetting it to a lower level and see what happens, might would go a bit lower than what you think should remain in it and kinda zero in on too little to where it runs good,if it does. Still sounds like that is the problem, and if not at least it eliminates that question and you can move on to the next. I assume you did check that the float does not have tiny holes in it and has fuel in the float , and that the needle and seat are OK and moveing freely.0
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The pump pressure will remain on the line to the carbs untill it has time to equalize. If the needles are holding good and the valves in the pump holding it wil take a while. If the needles are not holding this will let the bowl over fill. If you are running a fuel pump other than the correct Hudson pump it may have more pressure than the needles will hold. I believe the AMC pump has about twice the pressure of the Hudson pump. If you are useing the AMC pump do as someone has already posted and cet a regulator Set it ar 2 to 2 1/2 psi. I also set the float level about 1/8 lower as per Geoff C.0
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VERY GOOD , and all is correct, He's haveing trouble settleing down to traceing the problem , I have allways felt and will that begining at the start and not skipping any checks will eventually locate the problem on anything. proper pressure is essential, then the float setting and needle and seat. If they are all OK any pressure will not cause any problem as the float/needle seat is designed to withstand it. If that does'nt stop it then he would have to go deeper into the carb, Don't want to take him there untill the most common easy fix things are done and the carb then needs at least a tear down and good cleaning or maybe even a rebuild.0
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Just to make sure we all on the same page, here is a picture of measuring the float level of a Carter WA-1 carburetor. The original specification for the float level of a WA-1-968-S carburetor was 0.5 inch.
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Let me go over everything to this point. In July I rebuilt both carbs, gunked flushed and rebuilt. Both floats were in good shape. The car starts and idles fine, runs up to midrange just fine, put your foot in it and it gags and pops. About three weeks ago tank went dry and filter was plugged bad. I pulled the tank and had it dipped and flushed, put in new fuel lines with original Hudson pump, from the tank to the carbs. Still starts and runs fine up to midrange, but if at idle very long carbs start leaking gas, still no high range but if I shut off the engine gas keeps dribbling down the carbs throat. I'm wondering if I have a cracked bowl, though the bowl never goes dry. When I pulled the top the other day I had to suction out 3 or 4 ounces of gas and that was about an hour after I shut it off. I am perplexed. Also when I pull the top off the screened chamber over the bowl the chambers are still full so the needle must be seating.
Harry0 -
A question, do both carbs leak gas or just one? It is not true that if there is gas in the screened chamber the needle must be seating. Remember that when the car is running the needle and float are under pressure and when the car is stopped there less pressure or no pressure and the needle and float could hold the lower pressure or the float bowl is fulled up into the screened chamber.0
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The picture is correct. I set the carb to the specs on the kit. Now, bowl cannot be full up into chamber, the anti percolation valve would be pouring fuel out the top if that were the case.
Harry0 -
Can I assume that both carbs are leaking gas into carburetor throat at idle and stopped?0
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I knew someone would ask that and I won't be able to answer for sure until I get the first carb back together. I would like to say yes but after a few days I can't remember for sure. Saturday I'll put the carb top back and I'll let you know then. If the float is set to .5" then it will be higher in the bowl than it is now if I set them at 9/16".
Harry0 -
HARRY, Let me make one more suggestion, sometimes 2 heads are better than 1, and then sometimes too many heads cause confusion. Follow the leader not the pack. Looks like MARRS 55 knows what he's doing and is doing what I would do, start at one place,check it then the next in the order of the way things happen, and up tp speed on everything done is an absolute essential , Lets see what just the 2 of you come up with, follow him and keep him updated, dont change anything unlees agreed on and don't wander off on other ideas. and I bet you get it fixed, Marrs, what you think about the needle/seat being proper, seat not fully down, parts a bit off orig specs could throw the float level off0
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37 Terraplane#2 wrote:Marrs, what you think about the needle/seat being proper, seat not fully down, parts a bit off orig specs could throw the float level off
This is good point, just because the parts are new does not mean they can not be bad. Harry I know you started rebuilting your carbs in the July time frame, were the carbs leaking before you rebuilt them?
Setting the float at 9/16" would make the carbs run leaner then the 1/2" setting because the gas level in the float bowl would lower which in this case is good thing.0 -
That's a pretty idea except that someone may come up the right idea and I don't want to ignore any offers that could end my misery. MARS55 is coming up with good ideas though and I really appreciate all the help he is giving. I'm not even sure we are focusing on the right problem. I'm not sure which problem I should be giving my attention to. I'm not even sure the carbs didn't always dribble a little fuel right after the car shut off. Has any one else looked to see if their carbs dribble some right after they shut the engine off? I looked at the gas I pulled out of the carb when I pulled the top off and there was a lot of crud in it from when the filter clogged. So I'll pull the float valve before I put it back together and make sure there isn't anything in the seat.
Harry0 -
Harry Hill wrote:Let me go over everything to this point. In July I rebuilt both carbs, gunked flushed and rebuilt. Both floats were in good shape. The car starts and idles fine, runs up to midrange just fine, put your foot in it and it gags and pops. About three weeks ago tank went dry and filter was plugged bad. I pulled the tank and had it dipped and flushed, put in new fuel lines with original Hudson pump, from the tank to the carbs. Still starts and runs fine up to midrange, but if at idle very long carbs start leaking gas, still no high range but if I shut off the engine gas keeps dribbling down the carbs throat. I'm wondering if I have a cracked bowl, though the bowl never goes dry. When I pulled the top the other day I had to suction out 3 or 4 ounces of gas and that was about an hour after I shut it off. I am perplexed. Also when I pull the top off the screened chamber over the bowl the chambers are still full so the needle must be seating.
Harry
Questions from this:
1. Was there leakage before the filter plugged up?
2. Does it keep idling good after the carbs start leaking?
3. Did the carbs leak before you rebuilt them?0 -
1. There was no leakage that I know of before the filter plugged up.
2. The engine still idles fine.
3. I don't think so, I rebuilt the carbs because the engine had sat for five years without running. I've never looked into the carbs immediately after shutting the engine off so I don't know if the dribble was there before the filter plugged or not. It may have because one thing I learned was to never touch the gas peddle when starting once the car warmed up or it would flood. Simple toremember, get in , turn the key, fires right up. The only problem I had was the high end acting like the carbs were starving for fuel.
Harry0 -
After studying the WA-1 carburetor, I see something that could cause your problem and that is the Anti-Percolator Valve.
1. Did you replace the Anti-Percolator Valve seal when you rebuilt your carbs?
2. Is the Anti-Percolator Valve open when the throttle is closed and closed when the throttle is open?
3. Is the Anti-Percolator Valve making a good seal when it is closed?0 -
1.yep, replaced the seals when I rebuilt the carbs.
2. The anti perc valve starts out closed and opens when the throttle opens.
3. I don't know how good the seal is, a tiny coil spring holds it closed but it doesn't apply much pressure.
Since it is closed when the car is idling and the float stops the fuel from filling the bowl, unless the fuel is really getting sloshed around the anti perc valve should never leak. I was suspicious of the anti perc valve also but the gap is at least a half inch from the fuel to the top.
Harry0 -
The Hudson with the Packard v8 and two barrel has a return line from the top of the carb to the gas tank. Don't know if the Twin-H 6 has this. Do you have the original gas cap on the vehicle with the 'H' on it?0
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Yes sir, it has the original cap with the H on it, there are a couple of small holes in the locking part of the cap and a rubber gasket so that is probably the vent.
Harry0 -
Correction, the anti perc valve starts out open and closes when the throttle opens.
Harry0
This discussion has been closed.
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