Mechanical Fuel Pump for a Chevy 350

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madibob

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My dad has a '57 Chevy with a rebuilt Chevy 350 he installed about 10 years ago. Lately it's been hard starting after it sits a couple weeks or longer due to not getting fuel (we have to pour gas in the carb to get it running). The engine was built with what I believe is a standard fuel pump from NAPA. I'm wondering if there's something better I should look at replacing it with.

Few more details - the engine was built from a 350 4 bolt main block, has double hump heads (1.94-inch intake valves and 1.5-inch exhaust valves), Edelbrock intake, and an Edelbrock carburetor. It's not super high horse, but guess it's around 350hp. I'm sure a standard pump is fine volume wise, but wondering if there's something of better quality I should look at.

Thanks guys.
 
Since its all Edelbrocked up, how about Edelbrock. Holley also makes nice fuel pumps and if they haven't gone to pot lately Carter does too...

Of course a Sniper would fix all those problems too
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Once the engine is running, does it restart easily? There should be a check valve in the pump. Installing one between the pump and the carb may work.Priming carbs is as old as gasoline engines Charlie's weekend truck, a '46 Ford dump truck, had a dish on the oil bath filter. He just backed off the wing nut and poured the bowl full of gas. Truck would start and run the rest of the day without issues.
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Those edelbrock carbs are garbage! I have had 3 over the years and if they sit 3 days they won't start until fuel gets in the bowl. No way to fix them I could find.

Replacing it with a 1850 holley will get you easier starting and much more power.
 
Of course it hard starting after sitting. The fuel in bowl is likely dried up. I dont think you can address that.

Have you re - jetted that carb ( AFB/AVS) for your application? They tend to be pig rich out of the box on the primaries.
These days I run a 90's rochester 2 hole TBI with a dash controller and closed loop a/f management.
 
Originally Posted by rollinpete
Does it have a manual choke?
If it runs good once it starts I would thing fuel pump is okay.
It does not have a manual choke. Yes, once it starts it's fine all day. After a week or two you need to pour gas in the carb to get it going.

Originally Posted by andyd
There should be a check valve in the pump.
From what I read I think this is the problem.
 
Originally Posted by ARCOgraphite
Of course it hard starting after sitting. The fuel in bowl is likely dried up. I dont think you can address that.
It never did this before. Even after sitting all winter it would start. Yes, the first start after winter took 5+ seconds of cranking and she'd fire up. Now after 2+ weeks you can crank all you want and it won't start.
 
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With the ethanol fuel in a vented carb system, the fuel will evaporate quickly after you shut it down from the heat and time will do the rest. I had a 750 Edelbrock carb on a Dodge 440. and it would do the same thing as yours. I took the top off the carb one day just to see if there was fuel in the bowls......nope bone dry. The way these carbs are built it is impossible to siphon out after shutting down. So.....I started pulling the 90° PCV out of the valve cover and twisted it so opening was upright and squirted fuel into it. It cranked right up as the engine run just long enough for the fuel pump to refill the bowls again. OR..............You could install a good electric fuel pump and bypass the stock manual one. I like things simple, so I ran a stock manual fuel pump, I think it was from NAPA, never had a problem with the car running after it was started.
 
Originally Posted by oldhp
With the ethanol fuel in a vented carb system, the fuel will evaporate quickly after you shut it down from the heat and time will do the rest.
We run non-ethanol gas all the time.
 
There should be fuel up to the pump and a few seconds of cranking should be enough to get something in the bowls.
Ebrock and holley pumps are good and rebuild-able.

Also check your fuel tank venting system. There could be a big vacuum there and its sucking the fuel out of the lines as the car sits causing the pump to lose its prime.
Or it really could be a bad fuel pump with a bad valve that is letting the fuel drain back to the tank.
 
Originally Posted by CrAlt

Or it really could be a bad fuel pump with a bad valve that is letting the fuel drain back to the tank.

The needles and seats ( it has 2) are in the top of the carb. I dont see how it could pull fuel out. But stranger things have happened.
 
If it runs fine after starting, especially under load, the pump is probably OK.
When cold, manually work the throttle and look down the carb. If there are not strong shots of fuel then the bowl is dry.

Throwing parts at the problem without diagnosing is expensive and may not fix the problem.
My vote is it is a carb issue.
Good luck.
 
Originally Posted by Chris142
Originally Posted by CrAlt

Or it really could be a bad fuel pump with a bad valve that is letting the fuel drain back to the tank.

The needles and seats ( it has 2) are in the top of the carb. I dont see how it could pull fuel out. But stranger things have happened.


Car sits for weeks
Fuel evaps out of carb
Float drops then needle valves open
 
Originally Posted by madibob
the engine was built from a 350 4 bolt main block, has double hump heads (1.94-inch intake valves and 1.5-inch exhaust valves), Edelbrock intake, and an Edelbrock carburetor. It's not super high horse, but guess it's around 350hp.


In your dreams.
275 HP on a good day if you're lucky.

Anyways, you can always add a small 12v electric fuel pump - - That will fix all of your problems.

Carb + mechanical fuel pump + sitting a long time = Need to prime the carb... ALWAYS.
ALWAYS.

You can't ever expect anything else from anything that doesn't get driven regularly, period.
 
Originally Posted by JeffKeryk

My vote is it is a carb issue.


My thoughts too. An electric pump will refill the float bowl quickly, but it sounds like it's leaking out over time. Unless you live in the desert, it shouldn't evaporate in a week.
 
Originally Posted by Linctex

Anyways, you can always add a small 12v electric fuel pump - - That will fix all of your problems.

Carb + mechanical fuel pump + sitting a long time = Need to prime the carb... ALWAYS.
ALWAYS.

You can't ever expect anything else from anything that doesn't get driven regularly, period.

Sorry, I'm gonna have to disagree.

We've got a 1970 VW Beetle that hasn't been driven since October 2018 (steering column bracket is broken, haven't had a chance to fix it). In that time it has only been started once, about 2 months ago in the first half of March. The gas is E10 87 octane from September.

So just for this, I went out and filmed a startup video of it. I didn't pay attention at first and I forgot it was in gear. Then the old starter grinded. I gave it 10 pumps of the gas pedal.

This is not a freshly built engine, it's an unknown 1969 engine. My aunt bought the car 5 years ago and we haven't touched the carb. In 5 years it's driven 6k miles. Since February 2017 it's been driven 714 miles.
 
Originally Posted by Malo83
Get a Quadrajet for that small block.
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If you do make sure it has the check valve in the fuel inlet. The 77 chev in my sig has an 800 cfm Edlebrock that loses prime so will go back to the Quad. Also since we don`t know what the compression is or the cam grind is then how can hp be determined?
 
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