Holley carb 2300 350 cfm jetting and adjust help

snoddas · Aug 18, 2017

Hi Guys,
Have what I think an original engine. My Bronco spin like a cat at idle and super great throttle response but on the road it hesitate when accelerate.

When I purchase the car it dident run. I did some work at the carb (also the rest of the fuel system) and at the ignition/timing. After that It started right up which are great beside the problem when accelerate.

The main jets is 61/61 and the squirter is 31.
Power valve 6.5 (open vacuum 17 "hg)
Manuel choke

I have a new acc pump but dont know the status of the cam. It looks like the cam is orange and are mounted in the first (digit 1) hole. Could the cam even be worn out?

What do you guys think, okay jetting? It feels like the acc pump are the problem or?

I have the orignal Ford Electric magnet distributor (non Point) with vacuum attached and new ignition wires/spark plugs. Portet vacuum is 20 "hg at approx. 2000 rpm.

Thanks,
Anders

DirtDonk · Aug 18, 2017

Hey Anders. Thanks for putting some pretty good details into the question.
I can't help with the jetting, but agree that it sounds also as if the accelerator pump could be adjusted some. However I would wait until you get the main jetting dialed in, if someone here can tell from your numbers that you need larger jets.
Seems to me just off the top of my head that #61's should be fine. But I'm no Holley expert, but there are many here.

Seems too, like the power valve could be at fault. Not that it's a bad rating at 17", but if it's faulty it will give symptoms like you describe too.

Sounds like you do have your vacuum advance hose on the ported vacuum fitting on the carb. Often when you connect it to full vacuum it also acts like you're experiencing.

I would also double check the ignition timing with the light and put it to at least 10° BTDC. Maybe even experiment with more to see if it minimizes the hesitation.
Some engines prefer 10 to 12 degrees, while others like more in the 14-15 range.

Good luck.

Paul

snoddas · Aug 18, 2017

Thanks for the response Paul. I did forget to mention that its a 302 engine.
Yes its connected to the the carberators ported vacuum.

When I pulled the carb apart it did have a 8.5 Power valve but since I have a new one which was including the holley rebuild kit I installed that one instead it was the 6.5 one. I dident had measure/test the vacuum then.

/Anders

Joe473 · Aug 18, 2017

2 things on the powervalve. Go with one of the thicker gaskets. I think i ordered the thicker quick fuel or holley from summit. The thin ones from the carb kits cause drips. To check take carb off the truck. Remove power valve cover. Fill bowl with gas. If it drips and the powervalve diaphragm is good the gasket is the issue.

On the size of the powervalve keep in mind the smaller number opens at a lower vacuum. Meaning light throttle acceleration will be impacted lean if too small of a number. On a stock engine I would go no lower than 7.5 and 8.5 should be closer to correct. Check your vacuum at idle it should be 18-21 which puts you in 8.5 -9.5 range based on guidance out there.

Once the power valve is correct read your plugs for jets. I'm using a 4100 so my jet sizes will not cross over but my power valve experience will.

On a modified 347 .512 lift cam I'm using a 7.5 PV. No hesitation and very good all around.

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snoddas · Aug 18, 2017

Thanks. Will install the old 8.5 power valve. The 6.5 from the kit is what I have had till now, have the carb out of the truck at the moment.

jckkys · Aug 18, 2017

Holley 2300s were either 500 or 350 CFM except for a couple obscure models. The 350 CFM is the only reasonable choice for a 289 or 302 in near stock condition. The average 350 CFM 2300 has .031" accelerator pump nozzles and a 8.5"Hg power valve. The smallest white cam in the #1 position displaces 17cc per stroke. This more than enough for 1.5" throttle bore. Your hesitation is more likely either slack in the accelerator pump linkage or a missing check ball or weight. It needs both. With fuel in the float bowl and the engine warm and not running, look down the venturis while slightly moving the throttle lever. ANY movement has to result in fuel squirting out of the nozzles onto the booster venturis, or the engine will hesitate under load. It may sound OK in neutral/park but hesitate when it has to move your truck.
Slack in the accelerator pump linkage is taken up at the override spring screw.

snoddas · Aug 19, 2017

Thanks for great reply. Yes its the Holley list 7448 carb.
Will check thoose things again. I assume its ok then to have 0 clearance between the acc pump arm and throttle linkage (adjust screw).

Will the main jets work 61/61?

I have a ball in the fuel bowl (acc pump attach), is it the same as the weight or is it another part? Its a check valve is'ent?

jckkys · Aug 19, 2017

The List# 7448 was designed for 460 engines in light trucks, but is also listed for general use in other engines without emissions restrictions. The stock jets are 61s. The check ball and weight I'm referring to are under the accelerator pump nozzle. It prevents fuel in the internal passage from returning to the float bowl. If missing, some of the pump shot goes to refilling the passage instead of squirting out of the nozzle.

snoddas · Aug 20, 2017

Hi again,
Cleaned the carb and installed the 8.5 Power valve instead of the 6.5 - adjusted the acc pump arm with snug fit.
Checked timing with vaccum plugged. At idle it was close to 12 degrees.

Took it for a ride, no air cleaner and open vacuum plugged.
Now the Bronco accelerate as I want it to do!!! Very happy.

Mount the air cleaner, pcv-valve to open vaccum and even the other side valve cover cranck case ventilation to the air cleaner. I got a little bit more rpm at idle but the car accelerate as the test drive Before. Lower the idle and for the moment everything is great.

Thanks for the help guys!

Joe473 · Aug 20, 2017

snoddas said:
Hi again,
Cleaned the carb and installed the 8.5 Power valve instead of the 6.5 - adjusted the acc pump arm with snug fit.
Checked timing with vaccum plugged. At idle it was close to 12 degrees.

Took it for a ride, no air cleaner and open vacuum plugged.
Now the Bronco accelerate as I want it to do!!! Very happy.

Mount the air cleaner, pcv-valve to open vaccum and even the other side valve cover cranck case ventilation to the air cleaner. I got a little bit more rpm at idle but the car accelerate as the test drive Before. Lower the idle and for the moment everything is great.

Thanks for the help guys!

Good to hear. Now go for a 10 mile highway cruise and pull the plugs to confirm those 61 jets are good.

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Holley carb 2300 350 cfm jetting and adjust help

snoddas

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DirtDonk

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snoddas

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Joe473

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snoddas

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jckkys

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snoddas

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jckkys

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snoddas

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Joe473

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