Which carb?

[jeffncs]

I have a like new Holley 600cfm vacuum secondaries, e-choke that has NEVER run well. I’ve had it on a 351w and a 302 - it always ran super rich. Now it’s leaking fuel from the vac secondaries and dumping fuel into the intake.

I have an eye on 2 carbs (both refurbished with warranty).

Holley 600cfm - essentially identical to that which is on the engine now. $350

Edelbrock - same specs but it’s an Edelbrock. $260

Or should I try jetting down my carb after throwing a seal kit at it?

My engine is a ‘94 5.0HO with a c4.

Of those 2 options - which would you buy? I’m not going EFI. Thanks in advance!

 

[cldonley]

Sounds like it needs the seal kit and maybe a float adjustment. Reducing the jet size may be a good idea. I'd definitely try to re-jet with a carb kit before I'd spend money on a carb with the exact same specs. I'd also make sure the secondaries aren't opening too early.

 

[Pa PITT]

I'd try the kit 1st & adjusting the floats.also ,That a good carb If you can get it fixed . But you sure don't want it dumping fuel into the intakes ..

 

[Broncobowsher]

Holley dumping fuel out the secondaries is often just garbage got to the needle and seat not allowing it to close off completely. The fuel bowl over fills and eventually starts dripping out the secondaries. I've done it twice. Both times was a sliver of rubber fuel hose.

Invest in a rebuild kit before dumping that much money into a used carb. What you describe sounds like something that can be fixed, not need replacing.

 

[acropilot]

Yep I've had trash under the float needle a few times myself that causes fuel to spill into the secondaries or primary's which ever the needle is causing the issue.As far as running rich before that you may want to check the power valve which would be screwed into the metering plate on the primary side.Sometimes a backfire will blow them and allow excessive fuel creating a rich mixture and be very easy to replace.As far as the needle you can just unscrew from the top and clean it then replace and adjust the fuel bowl level but also a high fuel bowl level can cause rich issues too.Let us know if any of this works.

 

[BroncoJimbo]

I had the Holley 600 on my 351W for years and got pretty good at cleaning out the fuel needle on the side of the road. I switched it out for a TA 470 and it has been flawless.

 

[jeffncs]

Thanks to all! I think I have enough parts in a partially used rebuild kit to check the needles, replace the power valve and reseal ahead of adjust the floats.

I’ll give it a shot tonight!

 

[acropilot]

I've been running a quality filter on my builds these days right before the carb and haven't had any issues with trash cause float needle problems.

 

[Broncobowsher]

I've been running a quality filter on my builds these days right before the carb and haven't had any issues with trash cause float needle problems.

My issues were post filter. A sliver of rubber hose from sliding the hose over the nipples would break loose and find its way to the needle and seat.

 

[jeffncs]

So I popped the fuel bowls off to clean things up. Superficially - super clean. Looking closer, I found 1 fuel port at each end partially clogged with aluminum flashing. I also found the metering plate screws were super loose.

I pulled the chunks out, sprayed things out real good and swapped the power valve. Some new gaskets sealed it up. It had 66 jets which were the smallest I had on hand so they want back into the carb!

Dropped the carb on and set the float heights (adjusted to a small drip from the sight plug and tightened things up.

Truck still won’t run… no leaks at least!

 

[acropilot]

Doesn’t run at all or just still runs bad?

 

[jeffncs]

Doesn’t run at all or just still runs bad?

Doesn’t run at all…. even after the quickie cleaning I did last night. I’m going to post a comprehensive summary of all work done and ask for advice. It’s a ground up build that I’ve never heard run so lots of variables.