After shutting off the engine after a good run, I can see fuel continuing to flow/ooze from the squirter tubes into the venturies of my single downdraft 97 carb. This, of course, contributes to the "gassy" smell in the garage that Mrs. H. dislikes. Car has electric fuel pump (2.5 lbs pressure), engine block, aluminum intake manifold, and carburetor body are all hot to the touch a few moments after shutoff. I suspect that these parts are not as hot whe the car is running because of the effect of air movement under the hood. Will a phenolic spacer (insulator) between the carb and intake help with the percolation? Any other ideas? thanks in advance.
A insulator sure won't hurt. The biggest problem is modern fuel ,it boils at a lower temp than what we got 10-20 years ago.
Our phenolic risers have cured a lot of carb boiling problems, or heat soak as it is also know. I've had a lot of happy Hot Rodders, we have them for many different carbs.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o> <o></o> Dashman's Hot Rod & Speed Parts<o></o> <o></o> www.dashman.net<o></o>
Had some strange computer issues with last post. Here's some pics. Dashman's Hot Rod & Speed Parts www.dashman.net Stromberg 97 Ford Holley 94 Stromberg WW Rochester 2G
Phenolic spacers actually transfer a lot of heat but better than nothing, An aluminum spacer actually will cool down faster than the phenoilic one. You might want to fabricate a simple sheet metal plate to go between the carb and manifold a bit larger than the float bowl, to block some of the heat coming off the block. In regard to the weeping after shut down, set the float a bit lower than factory, a couple 32nds usually does the trick, and make sure thee is no debris in your needle ad seat as it will hold the valve open and allow residual pressure from the pump to try to keep filling the bow. If its been doing this for a while take a smell of the oil on your dipstick if it smells gassy, change it.
A more simple soulution would be to shut the pump off about 20 feet before you turn into the Garage!!
My truck used to leak fuel out of the carb after it was hot but once I put a foam like material spacer in between the carb and intake it didn't do it anymore. The spacer came with one of my edelbrock carbs so maybe you could find it on their website.
As has been mentioned the carb spacer/insulator is a good idea. You may also check the fuel lever in the float bowl, I don't know that it will help but we had a flatty years ago in the old leaded fuel that would boil and flood when we shut it off and it turned out that the fuel level was too high. It probably still perked but at least it didn't flood when it was hot.
The only way fuel can get past the powervalve into the discharge circuit would be if the powervalve itself is hanging open. I would suspect a damaged powervalve or powervalve gasket...
good to fix this ASAP. likely internal carb problem. heard of a guy working on a customer's car with same type of problem. he replaced carb. oil smelled of gas, so went to do a oil change. he was laying on a section of carpet and used a standard light bulb type drop light hanging from frame. turns out that the pan had a lot of gas in it and when drain plug removed it flowed out very fast and splashed on drop light. instant fire!! lucky another buddy showed up at that exact moment and grabbed his legs and pulled him out from under car. carpet helped contain gas, but serious damage to car and some to shop.
A powervalve opens at vacuum readings below the number stamped on it, when shut off you have 0 vacuum therefor the valve will always be open when the engine is not running.
Do you think this will be enough aluminum spacer between the intake and carb? Dashman's Hot Rod & Speed Parts www.dashman.net I think I would also take the advice on the adjustment.
Just to throw another opinion out there to confuse you. I had the exact same problem. THe cure for me was a 2" black plastic spacer. Even at the engines hottest, you can touch it with your hand. Stopped the boiling immediately, Aluminum spacer did not work. HTH Cheers and beers Hodge
What I did for my Stude pickup when it kept boiling the carb was to turn off the electric pump as I approached a parking lot or driveway before I came to a stop, so the carb wouldn't be full. After I got tired of that, or tired of hard starting when I forgot to turn the pump off early, was to buy a fuel filter I used to see on AMC's and other smog-carbed cars of the early 80's. Many of them, if not most makes of cars, used what looked like an ordinary fuel filter with an extra outlet. That extra outlet is for a fuel return line that runs back to the tank. The reason for most vapor-lock (also helps with most carb boiling probs), is that the fuel inches it's way along inside the fuel line, picking up more and more heat as it slowly crawls along. By the time it reaches the carb it is either boiling or very close to it. Adding the filter with the built in tiny orifice and return line will keep the fuel moving along, the hot fuel will return to the tank for cooling, and cooler fuel will replace it in the lines near the carb. That usually keeps slow moving fuel from just sitting there collecting heat. I used to see those filters hanging on the racks with the "normal" filters at Wal Mart Ace Napa and everywhere. If they are no longer as common as they used to be, just go to the parts counter, tell them you drive a "1977 PACER" and need a fuel filter. I don't know if ALL the filters will have the tiny orifice in the return outlet to keep you from starving the carb, but the AMC ones certainly did. If yours doesn't have a restrictor orifice built in, you may dump too much fuel pressure back to the tank, and have to restrict your return line in order to feed the carb, but every one of the AMC fuel filters I have used were just right. Here are some pics of what they usually looked like, so you can know when you find one. Just make sure the return line isn't too free-flowing or you could starve the carb. All the ones I have used have had the restrictor built into the small extra-outlet. I just can't assure you that ALL of them use one. The ones I have seen on factory AMC cars have all been mounted not too far from the carb. If you mount them too far back in the fuel system, it will defeat the purpose of keeping the fuel cool at the carb. P.S. This style of filter and recirc flow, will only work when mounted after the pump, on the pressure (output) side of it. The closer you mount the recirculating filter to the front, the less hot fuel you will have in the system. IF YOU DON'T WANT TO USE AN ELECTRIC PUMP, AND WANT TO KEEP THE FUEL SYSTEM AS STOCK AS POSSIBLE, THIS RECIRCULATING FILTER CAN BE USED VERY SUCCESSFULLY WITH THE STOCK MECHANICAL PUMP IF YOU MOUNT THE FILTER NEAR THE CARB, AND RUN ONE SIMPLE RETURN LINE TO THE TANK. THAT IS HOW AMC DID IT. IT WILL STILL KEEP THE FUEL COOL BY VIRTUE OF A SLOW CONSTANT FLOW.
Good info, but the price of the filters is way too high! Imagine having to tell someone that you drive a Pacer!
That's sometimes the price you have to pay to correct a problem! I used to pay only a couple dollars for the Fram filters on the peg-board at Wal Mart, and I didn't even have to tell them I drive a STUDEBAKER. Maybe they have gone up to 4 dollars or more? OK, if it's an image problem, tell them you have a late 70's AMC JEEP, you can even leave off the AMC part, but it isn't as much fun to say it that way. C'mon! Don't chicken out- tell them you need a PACER fuel filter! I really embarrassed a friend by doing that. When he knocked a hole in his Jeep oil filter while a bunch of us were out 4 wheeling, I had to help him fix the crank bearings. He just about fainted when I ordered some 1965 RAMBLER rod bearings for his Jeep. He said "what are you doing? IT'S MY JEEP, A JEEP!", so I changed the order to 1977 PACER rod bearings. I can't describe his reaction then. The parts counter guy was laughing so hard he could hardly breathe. Hmmm, isn't there another thread where I should post this story?
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