Fuel issue with 1967 L79 (327/350)

[Joseph E.]

Hello,

I took my roadster out for a ride since it was such a beautiful day today but things didn't end well. I was running through the gears at a moderate pace when the engine stumbled and died just as I hit third gear. I pulled off to the side of the road and attempted to start the car, however, she wouldn't cooperate. I popped the hood and found fuel EVERYWHERE on the intake manifold along with a severely flooded carburetor. A towel was used to dry up this overflow as fast as possible to avoid a problem. I took the air cleaner off and turned the engine over while I was outside the car standing alongside the driver door. When the engine was turning over, fuel was coming out of the primary vent tube as if the carb was the geyser Old Faithful. Nothing I was able to do solved the problem so I had to have the car brought back home by flat bed. Would a stuck float cause such a flow of fuel through the primary vent tube while the engine was being turned over? Could this be a fuel pump related problem where the pump is putting out too much pressure, filling the fuel bowl and blowing the fuel out of the primary vent tube? Prior to today's dilemma, I never had any such issues with this car. I'm thinking stuck float but I would like some member input to confirm this or head me in another direction. The carburetor on the car is the original Holley that came with the L79 engine. Thanks and have a great holiday weekend.

Joe

[Leif A.]

Re: Fuel issue with 1967 L79 (327/350)

Could be a stuck float. You said it's the original carb that came with the car...has it ever been rebuilt? Try rapping the front and top of the primary fuel bowl with the plastic handle of a screwdriver and see if this might release the float (if stuck). How often does the car get driven and how far?
And, just because this is the NCRS and I feel like being picky, you don't have a roadster, you have a convertible. A roadster, typically, has no side windows and no top. I'm humoring myself...semantics and all that.

[Larry E.]

Re: Fuel issue with 1967 L79 (327/350)

It's been my experience that given enough time the float level screw/nut (Not there on the 67's) or the float
itself WILL BACK OFF A BIT AND THE FLOAT WILL BE HIGHER THEN IT SHOULD. This happened in the the
Spring with my 66 L75. Did not know this till I got judged and a little pool of fuel was present on the manifold.
(Never present before)
When I got home from judging I took my 5/8ths open end wrench and found the Screw/Nut had backed off a bit
when stored. Tightened them and eliminated the fuel leak on the manifold. Now working on my 66 L72 and when
taken out of storage the first thing I did was check the floats and THEY TOO HAD BACKED OFF(Counter clock wise).
Tightened them and now runs well. I have no clue why this happens but it did with me. Larry P.S. Maybe it is where
I store them(In Illinois) as the Temps in a years time could be 10 below 0) to 110 above. Maybe this makes
the metal move around a bit>Just AWAG.

[Joseph E.]

Re: Fuel issue with 1967 L79 (327/350)

Hello,

Thank you for the replies and the suggestions. I did try striking the primary fuel bowl with the plastic handle of a screwdriver while I was sidelined on the road. Unfortunately, it did not free the float if this is the problem. The car started easily and ran fine until about twenty minutes into my run when the problem arose. I try to take my cars out at least once or twice a month each to keep them running well and keep things moving. The '67 was last out about a month ago because the weather here was not cooperating and each weekend that I wanted to take her out, it rained. There have been instances when the car has sat for longer than a month but I've never encountered this issue before as a result of the car remaining idle for a long period of time. I usually run my cars for at least an hour when I do take them for a ride with the driving being a combination of local roads (25 to 35 mph speed limit) and highways where I can get them up to at least 60mph or so. I haven't rebuilt the carburetor during my ownership and I don't know whether or not the previous owner ever worked on the carburetor. Since striking the carburetor primary bowl did not improve matters, I'll take the next step and remove the carburetor and disassemble it for inspection. I am aware of the difference between a roadster and a convertible, however, it's a habit of mine to refer to my cars as roadsters even though it is not accurate to do so. Thank you very much for the replies. Have a great holiday weekend.

Joe

Joe

[Duke W.]

Re: Fuel issue with 1967 L79 (327/350)

If you say you saw fuel 'everywhere" it would have to come from a pressurized line leak. A stuck float would just dump fuel down the carb throats, not spray it all over the engine compartment. Do a careful inspection off all fuel lines and connections from the fuel fuel pump to the carb.

If you can't find anything have a helper start the car, while you look for leaks, and HAVE A FIRE EXTINGUISHER NEARBY.

Duke

[Joseph E.]

Re: Fuel issue with 1967 L79 (327/350)

Hello,

Fuel was not coming from a fuel line leaking. Instead, the fuel was being forced out of the vent tube of the primary side of the carb as the engine was turned over. I saw where the fuel was coming from since I watched the engine with the air cleaner removed as I tried to start it after it died. From there it spilled into the carburetor, over the sides of the primary side fuel bowl and cascaded down onto the intake manifold filling all of the valleys of the hot manifold with fuel. This could have ended much worse but I was able to avoid such a catastrophe. Thank you for all of the replies.

Joe

[Lawrence S.]

Re: Fuel issue with 1967 L79 (327/350)

Sounds to me like the float is stuck, or perhaps there is a lot of debris in the needle and seat. Look forward to hearing what the problem is.

Lawrence

[Joseph E.]

Re: Fuel issue with 1967 L79 (327/350)

Hello,

Do any of the members know what is the correct rebuild kit number for the 3810 carburetor? The numbers that I'm finding for this carburetor are 37-119 and 37-1537. However, each kit seems to contain different components. I'd like to obtain the proper kit to have on hand so that when I remove the carburetor I can freshen it up with new parts. Thank you all.

Joe

[James W.]

Re: Fuel issue with 1967 L79 (327/350)

Could be that the O-ring on the inlet needle and seat has went bad. I just had this happen on my '65 L79 with the Holley 2818-1/4150 carb. I replaced the inlet needle and seat assembly with a Viton tipped needle from Holley and installed the correct sized Viton O-ring. The Viton will tolerate the crappy pump gas. Call Holley at 866-464-6553 and ask for assistance getting the correct rrebuild kit. You can have it in 3 to 5 business days.

James

[Joseph E.]

Re: Fuel issue with 1967 L79 (327/350)

Hello,

Thank you for the reply James, however, the needle and seat assembly that you show in the photo listed are not the same as the needle and seat in my 1967 3810 carburetor. Your needle and seat are the externally adjustable type. The 3810 carburetor uses internal, non adjustable needle and seat assemblies that can only be adjusted when the fuel bowl is removed from the carburetor.

I have been thinking about replacing the primary fuel bowl because the external plug above the internal needle and seat assembly has to be sealed with epoxy to prevent leaks from beginning. I've used the JB weld epoxy in stick form which holds for a while against the incoming fuel but it does eventually break down and begin to leak. This epoxied plug is NOT the source of my current fuel leak problem. I've read in the archives to use cold weld epoxy that is more fuel resistant to resolve this leaky plug problem. Is the cold weld that is recommended the same as the JB weld that comes in two separate tubes which needs to be mixed together? Is there a good source for a correct replacement primary fuel bowl with the vent hole and vent arm assembly? If this part is not available, what would be the harm in replacing the primary fuel bowl on the Holley 3810 with the marine version of the original bowl? The only difference between the bowls is that the original style is vented whereas the marine style is not vented. Also, what is the purpose of this vent assembly on the original primary fuel bowl? Thank you to all who responded.

Joe