FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: BattlestarGalactic on August 23, 2020, 05:52:04 AM
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Ok, the rear carb on my pickup is dripping after shut off, drowning it and making it very hard to restart. I checked float levels, good. I replaced needles/seats as I found the o-rings were bad. Still dripping. I pulled that carb, flat filed the main body and replaced metering gasket. Still drips. UGH!!!
I've had carbs do this before, but I've never had one continue to do it even if I did my typical fixes like mentioned above. With three vehicles with quads on them, it is not uncommon for a random fix every few years. Strangely, the blower car's 660's have lived for over 10 yrs now with not so much as a screwdriver touching them and it sits for 7 months out of the year in storage. Note, when I did pull it off(before starting), the front bowl was very near empty, the rear was still full when I tipped it over to drain them before pulling the bowls off.
This is a 1850-6 600 Holley. What channel could be draining the fuel out of the front bowl just sitting there? It's not over pressurizing the needle/seat, as I've pulled the sight screw and it was still down below and it was still dripping fuel. I'm boggled?
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leaking around/thru the power valve?
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if it's leaking while shut off, it's most likely also leaking while running. My vote also the PV.
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Ohhhh, that makes sense. I was trying to figure out how gas could get through, but the PV makes sense. It likely is in as bad a shape as the o-rings on the needles! I will be going out shortly to pull it off and replace it, and will report back.
Thanks guys.
Oh, ya, the 660s don't have PVs!!! Guess that is why they never leak down!!
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Well, plan B. Didn't have a new one, but tested a second hand one in the spare parts box. Same issue. Guess I will hit summit for a couple new ones and try again.
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Just plug the pv vac channel and retest. that'll isolate it to the vac well and it'd have to be pv, pv gasket
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Where is it leaking from? Are you able to observe the drip or leak as it is occuring?
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what kind of fuel are you running.and does it only happen after a long drive.
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Just get a smokey mist from primary throttle bores in the one carb. No real drip to be seen. It happens as soon as you start and shut it off. You don't have to wait.
I do have some plugs, and i used a new gasket so I know that wasn't an issue.
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Fun Fact, with an assembled carb, you can vacuum test the PV well.
In this scenario another good place to vac test is the accelerator pump channel in metering block.
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Larry, I have flat filed the carb face and thought it was nice but still had a leak. So I brought the body down the street to the machine shop. He put it on his table and it was still off .010 plus. After he did his thing it was all set.
Hope you get lucky with the pv seal.
JB
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I have machines available that i can mill it but with a large flat file it is way closer then it was. I've never had one be so finicky.
It had blue gaskets, so I've been through this one before. The front carb is still fine, this one? I'm getting another quick kit from summit as a start.
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Check for a hole in the float make sure the spring is under the float this wont drain the bowl but will give trouble like your having.If the seat cant close all the way.
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Pretty sure I have black plastic floats in all my carbs, so no chance of sinking.
If it was overflowing, it should be coming out the sight hole, which it is not.
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Pretty sure I have black plastic floats in all my carbs, so no chance of sinking.
If it was overflowing, it should be coming out the sight hole, which it is not.
I have had black plastic floats "sink"
very frustrating, when I disassembled to check it out they would dry out enough to float again for a day or two.
I had to weigh them on a gram scale to prove it.
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Something I can check into. I have a digital gram scale that I use for my clutch tuning parts. I have jet extension on the wagon and have cut the heck out of those black floats with NO ill effects.
Though, like I mentioned, the fuel never comes out the float sight hole. Even when running or shut off. Motor runs flawlessly, idles perfect. It somehow drains the bowl, that is why I'm trying to figure out what passage from the bowl would allow that to happen. I did try another PV and NEW gasket which had no improvement. I have the carb torn down and will get all new parts.
Once I get a new gasket kit I am going to fill the bowls and mount the carb high enough to witness any fuel dripping from the bores. If nothing, then I'll put it on the truck and retest it. Just have to start it, maybe let it run for 30 seconds and shut it off.
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Doubt this is it, but have you made sure the vent on the tank is good? I had one that would get warm and pressurize the fuel system. Fought it until I figured it out one day....may tank had so much pressue I had to wait for dark to get the cap off and when I did...whoooosh, pop went the tank. The shoddy parts store cap had a bad spring in it or something. My tooth pic wedge is still in it 10 years later.
Again I doubt this is it, but it is easy to just crack the cap and see what happens.
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I get most all my carb parts online from Walker carb the new web site can be a pain but when you get to high performance parts.You will be ok they have all the parts you cant find anywhere.I like to buy just what i use and dont half to pay for a kit.
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Doubt this is it, but have you made sure the vent on the tank is good? I had one that would get warm and pressurize the fuel system. Fought it until I figured it out one day....may tank had so much pressue I had to wait for dark to get the cap off and when I did...whoooosh, pop went the tank. The shoddy parts store cap had a bad spring in it or something. My tooth pic wedge is still in it 10 years later.
Again I doubt this is it, but it is easy to just crack the cap and see what happens.
I run a fuel cell in the bed of the truck. It has a roll over valve, so it is vented. I also run 2x4 intake and I only have issue with one carb, so that eliminates that.
Thanks for the input. I know I've seen venting issues on stock tanks before.
I get most all my carb parts online from Walker carb the new web site can be a pain but when you get to high performance parts.You will be ok they have all the parts you cant find anywhere.I like to buy just what i use and dont half to pay for a kit.
Having Summit Racing just minutes away I just get stuff there for the most part since I don't have to wait for delivery. I used to buy just bowl gaskets and metering plate gaskets separately, but many times I need a PV and gasket or base plate gasket so I just buy the cheaper strip kit for $33 and get a nice selection of extra parts(like bowl screw gaskets and needle/seat gaskets). I get regular Summit bucks for $15 or so and that helps pay for the little stuff like this.
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We stopped their on the way home from the fe reunion nice place butt hard on the wallet to many deals.
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I once used a blue gasket from a QF kit and had problems. Got a Holley gasket and problem solved. Really went round and round on that one. Same carb as yours.
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Don terrills speedtech speed talk . com forum holley gurus id a leaking port please this site may help some of you out.
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We stoped their on the way home from the fe reunion nice place butt hard on the wallet to many deals.
I'm about 15 minutes south of Akron store. I peruse the return tables looking for bargains, though I don't make a regular trip up there. I've gotten some smokin' deals on stuff but there is a crowd that makes regular stops first thing in the morning to scoop up anything real good(A friend of mine is one). He has a speed shop in his basement from all the stuff he has bought on the junk table). :o
I once used a blue gasket from a QF kit and had problems. Got a Holley gasket and problem solved. Really went round and round on that one. Same carb as yours.
I've learned years ago, ONLY Holley parts/gaskets.
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Larry ,
One thing I was told to do after I modified "side hung " floats was to weigh the float before and after. My carb modifier friend said I should add bb's to the modified float ( or epoxy) to restore the original weight. The "light" float was "too" sensitive and messed with the fuel level in the bowl. I "corrected" mine and it made a difference.
Randy
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Interesting. The ones in the truck carbs are stock plastic. The wagons are cut up pretty badly for the extensions but has had no ill effects.