rejetting stock 2bbl Motorcraft carb for altitude

[Gunnibronco]

There is someone on CB.com who has brought their truck from TX to Crested Butte & can't get it running right. Its such a busy time in town right now, the shops can't get to work on his truck. I told him I'd be happy to help him, but I don't know much about carbs.

Can anyone give me a quick run down of what is involved with a jet change for the old stock carb?

Suggestions for jets?

I think we need to see what jets are in the carb, before trying new jets, but I haven't seen the truck, and he doesn't know what jets are in it.

Any help/advice would be appreciated, hoping I can help this guy out.

http://classicbroncos.com/forums/showth ... p?t=243669

[cravenbronco]

There is someone on CB.com who has brought their truck from TX to Crested Butte & can't get it running right. Its such a busy time in town right now, the shops can't get to work on his truck. I told him I'd be happy to help him, but I don't know much about carbs.

Can anyone give me a quick run down of what is involved with a jet change for the old stock carb?

Suggestions for jets?

I think we need to see what jets are in the carb, before trying new jets, but I haven't seen the truck, and he doesn't know what jets are in it.

Any help/advice would be appreciated, hoping I can help this guy out.

http://classicbroncos.com/forums/showth ... p?t=243669

what kind of carb is it and what altitudes does he plan on running it at?

[Gunnibronco]

Stock 2bbl on 302, I don't know exactly the part number maybe 2150.

Crested Butte is @ 9000'. He could easily touch 10000'+ and go as low as 6000'.

Talked to someone today, who said the power valve has failed. But I'm sure it needs rejeted too.

[sonrider]

Hello. I just moved to the Denver area from Phoenix, AZ and need to have my carb jetted for altitude. I have the same stock 2bbl Motorcraft carb. Can someone help me or point me in the right direction? Thanks.

Brian-

[Kinder]

I'd get a basic rebuild kit and make sure everything is in working order before I did anything else. And get some spray and soaking carb cleaner so all the openings are clear. I'd also make sure the ignition system is in good working order, new points/condenser (these have gotten expensive lately), rotor, cap, wires and plugs. Post up what the jets are that you currently have, they are numbered on the top where the slot is. Be careful when removing them, try to get the best fit with a properly sized flat blade screwdriver, if you don't and round the slot out you'll be in trouble.

[Gunnibronco]

Dave ended up dropping one jet from a 48 to a 44 jet, but we couldn't easily remove one of the jets, because it was stuck/stripped. I think we figured he could drop to around a 40 (based on derating 3% for every 1000' in elevation). We are a little higher in elevation than Denver.

I'd start where Kinder suggests, make SURE everything is working right (Dave's probably had a bad power valve- which makes it run rich, too), and what jets are in it. Then derate appropriately.

Then go EFI.

"bronco dlight" is Dave's screen name here, you can PM him, I'm sure he's happy to share anything he learned. I know he decided to can the carb & go EFI, which is the best choice.

[bronco dlight]

Dave ended up dropping one jet from a 48 to a 44 jet, but we couldn't easily remove one of the jets, because it was stuck/stripped. I think we figured he could drop to around a 40 (based on derating 3% for every 1000' in elevation). We are a little higher in elevation than Denver.

I'd start where Kinder suggests, make SURE everything is working right (Dave's probably had a bad power valve- which makes it run rich, too), and what jets are in it. Then derate appropriately.

Then go EFI.

"bronco dlight" is Dave's screen name here, you can PM him, I'm sure he's happy to share anything he learned. I know he decided to can the carb & go EFI, which is the best choice.

What Gunnibronco said. You absolutely MUST change out the jets to get it right if there is a significant elevation change. I was going from 60 to 9500 feet, so my case was an extreme. I had it at three different mechanics, none of whom wanted to rejet. They would mess with the timing and mixture and replace the plugs and it would run swell until I put a low speed load on it going up the mountain back to the house, but had totally fouled the plugs within 5 miles. I wanted to make sure I didn't run so lean I ran hot, so I watched a youtube on rejetting, ordered several sizes of jets, and I think I dropped the one jet 4 counts, as Gunni said. The other was too stripped to remove so I had four good and four bad cylinders. I could have simply bought a new carb, but in the end bought a '98 explorer donor instead.

I watched a carb tuning video this am. Sounds like I should have found this last summer!

https://www.youtube.com/watch?v=eF05KpuAOCs

[Unaweep]

Is the guy staying in CB (staying at high altitude) or traveling back and forth between high elevation and low elevation?

There is a model Q-Jet that automatically adjusts for altitude extremes like 10K to sea level.

Erik

[Gunnibronco]

His truck lives in CB. Right now its in Denver, getting Explorer EFI, so its not an issue anymore.

[sykanr0ng]

You guys all need to stick with carbs, no EFI for you.

I'm having enough trouble finding a cheap Explorer donor without your competition

[mickphatmac]

You guys all need to stick with carbs, no EFI for you.

I'm having enough trouble finding a cheap Explorer donor without your competition

For sykanrOng's Eyes ONLY!!!
http://denver.craigslist.org/pts/4910211712.html

[akaFrankCastle]

Summer time picture of a truck. No picture of the motor in question. No means to hear said motor run...

[sykanr0ng]

.....no idea what is missing/what else would need to be found/bought?
wiring harness? $$$
ECU? $$$
fuel pump? $
fuel lines? $

What I want is a whole (drivable preferred) Explorer 1996 first choice, 1997 second choice, 1998 distant third choice.

That way not only an engine but all related parts + rear brakes, overhead console, maybe seats, etc., etc.

And then sell the rest for parts or scrap and get some of the money back.
Possibly after driving it for a year or so before pulling it apart.