Fuel problem

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Sep 12, 2003 | 10:41 PM

Henryf250

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Joined: May 2003

Posts: 13

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Fuel problem

Hello everyone, I have a 69' 3/4 ton camper special w/ a 390. My problem seems to be lack of fuel under a load. At an idle the truck purs, but when I get under a load it is starving.

With that said I have a new holley 1850 series 650 cfm that ran great for about five miles. After I filled it with gas it started to run bad (this fuel starvation deal). I also have a new fuel pump and filter. Is there a possibility that the filter on the bottom of the fuel pump could be clogged? If so is there an easy way to remove this filter to check it?

As I stated earlier it did not start running poor until I filled it up with fuel. I may have been about to run out of fuel when I stopped to get gas. Do these fuel pumps have a hard time pumping the air out of the fuel lines? Sounds silly, but Im looking for any possibility. I thank you in advance for any info you are willing to pass on.

Sep 13, 2003 | 02:00 AM

NM5K

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Joined: Sep 2003

Posts: 497

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From: Houston TX

Fuel problem

Does sound tank crud related. Is your tank behind the seat, or under the truck? My tank that is behind the seat has no filter. Just a tube sticking in it that draws fuel. I had lots of rust and varnish problems when I first got my 68. It had sat in a garage for over three years, and the tank was varnish city. Also lots of fine rust that gets carried through the system. I had to pull the tank and clean it. On mine, the line itself once got clogged underneath the drivers side door. There is a little rubber hose that connects the long line to the shorter tank line. Mine got clogged with chunks of rust. I blew it out, and has been fine since. On mine, I use three fuel filters. I have one before the fuel pump that is clear plastic. " I can see if I'm getting gas". Then I have the stock filter in the fuel pump itself. I've had to clean it once after the tank problem. Was loaded with rust powder. Then I have another one yet, right before the carb. I like clean fuel.

I bet your tank had a fine coating of rust that got washed down to the bottom when you filled up. It's now clogging something. MK

Sep 13, 2003 | 08:02 PM

jwrboss302

Senior User

Joined: Apr 2003

Posts: 237

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From: ipswich USA

Fuel problem

The crud in the tank is a definite possibility. Another is the carb, have you checked the float level in both bowls on the 1850? There is a plug on pass side of carb for each bowl, float level is adjustable from the outside. I have a 460 with a 600 Holley in an F250 that would basically run out of steam on a grade with a loaded trailer. In its younger days, I could pass anything up a grade loaded or unloaded. I finally traced it to a low float level in the secondary bowl. Just my 2 cents of experience.

Jwrboss302

72 F250 CS
85 F250 4x4

Sep 13, 2003 | 10:08 PM

460 Crew

Elder User

Joined: Jan 2003

Posts: 730

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From: at my house

Fuel problem

That filter just unscrews to check it. And like the above said install a clear filter it will make you life alot easier to diagnose problems now and later with your fuel system.

Sep 14, 2003 | 10:06 AM

Henryf250

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Joined: May 2003

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Fuel problem

Thanks for the help guys. I replaces the filter at the pump and I get plenty of fuel now. It was the fine rust particles.

Now I have a new problem. It is with the carb, at low rpm it feels like a missing or popping, possible vacume leak but I can not find it.