Backfires when accelerator pressed down to take off

[firestoper 25]

THANK'S B.D., the above reply made my day....a good laugh is the best way to start a gray winter day ! Especially the plane part.....(same goes for a boat,eh as they say around here). We have a small locally owned gas / food store who has cash flow problems and as a result runs out of gas. I had two episodes of 'dirt' in the gas when I fueled up, one I limped home & changed the fuel filter however the other time it was a roll back trip to town for filter / injector cleaning.
We have a good rumor mill out here so when they run out of gas the word spreads to let the tourists buy the dirt-gas blend and deal with the results.
So Lark Hunter, I can't speak to your question of who / why in your area BUT I can sure tell you how it works in the rural Green Bay area.

[Big Dan]

LOL! At my age sometimes in the morning I'm a little forgetful and take two "Smart-A" pills instead of just the prescribed one. Gets me into trouble sometimes though!

[Big Dan]

THANK'S B.D., the above reply made my day....a good laugh is the best way to start a gray winter day ! Especially the plane part.....(same goes for a boat,eh as they say around here). We have a small locally owned gas / food store who has cash flow problems and as a result runs out of gas. I had two episodes of 'dirt' in the gas when I fueled up, one I limped home & changed the fuel filter however the other time it was a roll back trip to town for filter / injector cleaning.
We have a good rumor mill out here so when they run out of gas the word spreads to let the tourists buy the dirt-gas blend and deal with the results.
So Lark Hunter, I can't speak to your question of who / why in your area BUT I can sure tell you how it works in the rural Green Bay area.

Our weather here this time of year is what causes me most of the problems I have with fuel. We can go from a wet, rainy three days with temps down in the 40s (ok snow belt guys, no snickering) and the next day the temps swing from 30 in the morning with frost to 80 and muggy by the afternoon.

With that kind of swing, you'll get a lot of "breathing" on the part of your gas tank (That's one good reason to keep the tank full or close to it this time of year.) And if that gas is still down in the 40s and the tank is expanding and breathing in 80-degree air full of humidity, I can promise that eventually you'll have droplets of water in your tank, and carb. And the next night, it freezes to a solid - or worse a slush that will get sucked in the fuel system with all the particulates and "rust dust" from the bottom of your gas tank with it.

And when that happens, my truck runs exactly like the OP described.

I've actually poured a couple bottles of Isopropyl alcohol in the (20 gal) tank to bust that up, absorb the water, and help burn it out!

[Brianbo]

My money would be on the condenser. Mine would buck and backfire at times. Replaced the condenser and gapped the points and it runs great and helped with the hot starts. 90% of carburetor problems are electrical.

[jackb]

"90% of carburetor problems are electrical." That same comment was the rationale for the rebuild of the distributor. In my case, the engine ran no different. Do I possibly expect 2 bad condensers ? Maybe. Both were new when all these problems started in July. But my truck symptoms cleared with fresh 93 octane and no electrical changes...... ?!?

[Big Dan]

Well, not being argumentive, but with the crap being produced today and being sold as car parts, I think getting two (or possibly even all) bad new condensers is entirely possible. Re: the new Fuel pumps being sold for Champions. They have a design flaw and are ALL defective! Yet, they are still on the market! One of the BIG reasons I went with Pertronix!

[Big Dan]

"90% of carburetor problems are electrical." That same comment was the rationale for the rebuild of the distributor. In my case, the engine ran no different. Do I possibly expect 2 bad condensers ? Maybe. Both were new when all these problems started in July. But my truck symptoms cleared with fresh 93 octane and no electrical changes...... ?!?

Just out of curiosity, where are the gas tanks located in the Studebaker Trucks?

[jackb]

"Just out of curiosity, where are the gas tanks located in the Studebaker Trucks? "

under the driver's seat, mounted on frame rail....


and not to get lost in this shuffle: is the ethanol in today's gas different than the dry gas (isopropyl) you buy to absorb water in your fuel ?? Chemical engineers ? Is there a need for alcohol to be added to rid the system of water ?

[Big Dan]

Ethanol and isopropyl are different chemical compounds. You can drink Ethanol (it's the "fun potion" in alcoholic beverages). If you drink Isopropyl, it'll probably kill you. There's no "need" to use isopropyl to rid your fuel system of water, use of it just helps do it if you have a "water" problem.

[altair]

There is more to an accelerator pump than just the pump, at the base where the fuel enters the pump chamber there is a brass jet with a check ball inside if leaking the fuel will leak back. There is also a check needle valve at the top of the chamber where the fuel is delivered to the carburetor, again if leaking will bleed back and cause stumbling. The pump itself may be ok but these two accessories may be the problem.

[aftontrix]

Thanks for all of the input. I looked at and tried all of the suggestions and the engine now runs much better. Still not as smooth as it did. I did make a mistake. I had one of those senior moments a few weeks ago and filled up at Walmart. I know, bad gas. Is their any additive I might add to boost the octane that really works? In the future I will only use real ethyl gasoline. Thanks

[Big Dan]

Thanks for all of the input. I looked at and tried all of the suggestions and the engine now runs much better. Still not as smooth as it did. I did make a mistake. I had one of those senior moments a few weeks ago and filled up at Walmart. I know, bad gas. Is their any additive I might add to boost the octane that really works? In the future I will only use real ethyl gasoline. Thanks

I've found that when confronted by something like this it's usually not one singular issue, but a combination of a few and that last one just proved to be the straw that breaks the camel's back. So, you've probably "finessed" out all the little stuff.

Myself, I'd just drive the car daily at least to the warmup point - even if it's around the block a couple of times, run a couple tanks of good gas through it and that will probably help burn out all the bad stuff as well.

For my Ford Truck (390 FE w/750 Edelbrock carb), when it tends to ice up or I get bad, gas I just dump a bottle of the STP fuel system cleaner in it. It tends to make things worse for the first half of the tank, but I think that's because it's loosening up all the garbage and sending it up to get "eaten." It seems to help once that tank is gone, and I fill back up with good gas.