• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Prime the carb when the gas has evaporated? What do you guys do?

I have a 850 Thermo-quad. Looks like folks with the most amount of issues are the guys with AVS, Demon, and other variant of Carter carbs. Man, another reason to get a Holley!!

No way I would do the rubber squeeze thing.

I think I will just get a $12 primer bottle or just deal with cranking it for now as I would need a bubble hood to run a Holley with my intake.
 
My F.ILs 55 does that after sitting a week and the pump won't pick up, so I take an airhose with a rag and stick it in the fill nozzle and give a little blast. The pump picks right up and it lights off after a couple of seconds.
He also has one of those pita aircleaners that requires an allen wrench to take off...

The car hasn't started since Sunday. I plan to start it again on Thursday. It should be in a dry bowl state. What should I check?
 
The car hasn't started since Sunday. I plan to start it again on Thursday. It should be in a dry bowl state. What should Some Holleys have a sight glass you can shine a light in to see the level.
How old is your pump? is your push rod the right length to give a full stroke on the pump arm?
You could also install a clear filter to see if you have fuel on the high side of the pump.
 
I have a 850 Thermo-quad. Looks like folks with the most amount of issues are the guys with AVS, Demon, and other variant of Carter carbs. Man, another reason to get a Holley!!

No way I would do the rubber squeeze thing.

I think I will just get a $12 primer bottle or just deal with cranking it for now as I would need a bubble hood to run a Holley with my intake.
I am running the same thermoquad on my 73, and yes I do have fuel evaporate especially after a really good drive on a hot day, in a few days the fuel is gone. Keep in mind that the thermoquad bowls are vented very well to the atmosphere plus the charcoal canister if you are still stock like me and so the fuel will disappear over a few days if its not run. It was worse before i switched to ethanol free fuel, but evaporation is not as quick. I just went and got a 99 cent mustard style bottle and fill it with 3 ounces of fuel and prime via the front vent on the thermoquad, and five pumps of the gas and turn the key and she starts. I also let it sit for at least 5 minutes before starting because my accelerator pump I put in has the leather cup so its just to make sure its swelled back up before running.
 
I’m not a fan of electric fuel pumps.
I’d just crank it until it starts if you don’t want to prime the bowls.
limiting your cranking to 5 to 10 seconds will go a long way on preserving your starter. Heat is what kills it. I pump mine several times with the accelerator and then crank for a couple of seconds - let it sit and do that several times with copious intervals.
 
limiting your cranking to 5 to 10 seconds will go a long way on preserving your starter. Heat is what kills it. I pump mine several times with the accelerator and then crank for a couple of seconds - let it sit and do that several times with copious intervals.
I also have a ketchup bottle (plastic) about .50 at yard sales to prime somethimes.
 
It appears I've been drive-by red X'ed.
red x club small.jpg


Hey @forphorty - I don't mind a red "X" but at least be prepared to state why you disagree - or offer alternative ideas.
 
It isn't the car or the carburator type, it's the damn gas with ethanol in the gas. I live in northern Ohio near toleTo and we have refineries, ask them and they will tell you the gas now a days evaporates fast. Fill a 5 gallon can, leave the lid off and check it in a week. It'll be a half gallon less. Take a carburator with a vent hole and the gas will evaporate. You all that don't have that problem must still have ethanol free gas. Pull the air cleaner and squirt in some gas and he done with it. No magic fix.
 
I didn't make it clear in earlier posts that you put the squeeze bulb inline and you don't remove it. If your car has been sitting you just pop the hood and give it 3/4 squeezes and your all set, as Richard Cranium noted after adding the bulb. You could put it from frame rail to fuel pump or after fuel pump.
wid9.JPG
 
Wow great idea but..........., is the fuel exposed to that rubber bulb? Ethynol and that mix is lethal for the carburetor/s
 
How old is your pump? is your push rod the right length to give a full stroke on the pump arm?
You could also install a clear filter to see if you have fuel on the high side of the pump.

The fuel pump is about two year old with less than 2k miles on it. I actually have a glass filter in the parts bin, but the only place to install it is down low near the pump where I have a steel canister type filter as I have a hard line from the carb to near the pump.

I read in the "crank crank crank" thread that a check valve near the carb helps, but a good one costs as much as an electric fuel pump!! It seams like the only easy and cheap way to deal with it would be to manually prime it or use an inline electric fuel pump on a toggle switch to prime the carb before starting.

I would like to replace the 5/16 original hard line from the tank to pump with a larger 3/8" stainless steel line with a 1/4 return and a matching pickup. I would like to put a pump in or near the tank and a regulator on the frame rail near the existing mechanical fuel pump.

I'm just glad I'm not the only one with this issue.
 
I didn't make it clear in earlier posts that you put the squeeze bulb inline and you don't remove it. If your car has been sitting you just pop the hood and give it 3/4 squeezes and your all set, as Richard Cranium noted after adding the bulb. You could put it from frame rail to fuel pump or after fuel pump.View attachment 668610

Something about that just doesn't sit well with me.
 
It isn't the car or the carburator type, it's the damn gas with ethanol in the gas. I live in northern Ohio near toleTo and we have refineries, ask them and they will tell you the gas now a days evaporates fast. Fill a 5 gallon can, leave the lid off and check it in a week. It'll be a half gallon less. Take a carburator with a vent hole and the gas will evaporate. You all that don't have that problem must still have ethanol free gas. Pull the air cleaner and squirt in some gas and he done with it. No magic fix.
I have to disagree about the carb, some do a much better job of dissipating heat because of the design. Carter style carbs have more issues because they are a solid piece of aluminum with a top whereas the Holley style has 4 gaskets between the bowls and the intake... everytime heat hits a gasket more heat is lost in transfer.
 
It isn't the car or the carburator type, it's the damn gas with ethanol in the gas. I live in northern Ohio near toleTo and we have refineries, ask them and they will tell you the gas now a days evaporates fast. Fill a 5 gallon can, leave the lid off and check it in a week. It'll be a half gallon less. Take a carburator with a vent hole and the gas will evaporate. You all that don't have that problem must still have ethanol free gas. Pull the air cleaner and squirt in some gas and he done with it. No magic fix.
Tak419 is correct, I did an experiment last year when the debate in another thread was going on about fuel evaporation. Here is the experiment post I made. https://www.forbbodiesonly.com/mopa...ars-from-my-carb.137351/page-5#post-910766385

Ethanol fuel is a prime issue with evaporation and no matter the carburetor and insulators, they all will eventually suffer from heat soak and evaporate ethanol even faster. With the exception if you have a high rise that sits outside the engine compartment above the hood line!
 
Tak419 is correct, I did an experiment last year when the debate in another thread was going on about fuel evaporation. Here is the experiment post I made. https://www.forbbodiesonly.com/mopa...ars-from-my-carb.137351/page-5#post-910766385

Ethanol fuel is a prime issue with evaporation and no matter the carburetor and insulators, they all will eventually suffer from heat soak and evaporate ethanol even faster. With the exception if you have a high rise that sits outside the engine compartment above the hood line!
We all know ethanol is the problem but the one thing I don't see anybody talking about is boiling point which is much lower. Any heat that can be lost in transfer is going to help because it speeds up the evaporation. I did my own little test, the car would require lots of cranking to start after being thoroughly warmed, added a phenolic spacer and voila it got better, upgraded the carb... problem magically disappeared. Still had an issue with a stumble shortly after hot starts so I insulated the fuel line by the header and whataya no it only does it now if it's super hot outside and I have to sit in tranffic. I literally never have to crank away anymore??
 
We all know ethanol is the problem but the one thing I don't see anybody talking about is boiling point which is much lower. Any heat that can be lost in transfer is going to help because it speeds up the evaporation. I did my own little test, the car would require lots of cranking to start after being thoroughly warmed, added a phenolic spacer and voila it got better, upgraded the carb... problem magically disappeared. Still had an issue with a stumble shortly after hot starts so I insulated the fuel line by the header and whataya no it only does it now if it's super hot outside and I have to sit in tranffic. I literally never have to crank away anymore??
That's interesting, and good for you that you were able to get it fixed. I am sticking with my thermoquad, because my car is almost all original, but it does have a spacer, however, one thing I didn't mention before was the engine temp, I am guessing most people don't run 190 thermostats, but I do as my 340 likes to run when hot, never had any overheating issues, but with headers and that thermostat, boy is she hot when I park in the garage, I don't think any amount of insulation will help me with fuel evaporation.
 
Something I forgot to mention is that I bought a Street Demon 625 with the composite bowl for my wife's car...it sometimes sits a month but usually lights off almost instantly.
I know a lot of people think those are junk but it has been the most problem free carb I have ever had. It was spot on out of the box...and it didn't cost $500+
 
Auto Transport Service
Back
Top