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What am I doing wrong.

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
ok,

We all know that our bronco's aren't suppose to smell quite as 'mundane' as a brand new auto, but as I have gotten my 67 back on the road my wife is constantly b*tching about the exhaust smell. Here is what I have tried so far and what I have.

67 - 289/NP435
Holley reman - 2100, Carter 4070 electric fuel pump.
Explorer serpentine

It will start up immediately every time hot or cold, without having to use the choke. (i am not sure if this is good or a symptom of what I have wrong)
Idle's nicely at 900rpm pulling a steady 17 on the vacuum gauge. I have the idle/fuel screws at 1 1/2 turns out, that is where I got the best reading.

It smells like crud - I believe the term is running rich (but I have been wrong i the past on many ocassion). Since it smells like this at both idle and speed, do I need to look at the 'jets' and floats in the carb? Are these adjustable on a 2100 series carb?

Any help you can provide would be great as I have to do something to get the wife to stop complaining. The exhaust is routed properly out the side at the rear corners of the rig.

Thanks,
dan
 

Flash69

Bronco Guru
Joined
Jul 21, 2004
Messages
2,429
Loc.
Southwest Va
Do you have all the holes in the firewall sealed up good. That makes a difference. I cant tell you on the carb adjustments but you have the exhaust routed right. Good Luck getting the wife to quit complaining.
 

Heus33

Bronco Guru
Joined
Jun 1, 2005
Messages
7,407
Firewall holes and floor shifter mounts made my last one stink pretty bad - that was more like gas than exhaust though. Seal those suckers up if you haven't already.
 
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bannind

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
Right now this one isn't so much the fumes getting sucked into the cab, but the fumes themself. I am planning on going back through with the sealing bit later on.

My concerns at the moment are with the smell of the exhaust itself. I forgot to add in that I can also smell some gas when it is sitting in the garage. That is leading me to think that the floats might off.
 

deltarat

Bronco Guru
Joined
Jul 12, 2006
Messages
3,371
Loc.
Drew,Ms
It smells like crud - I believe the term is running rich (but I have been wrong i the past on many ocassion). Since it smells like this at both idle and speed, do I need to look at the 'jets' and floats in the carb? Are these adjustable on a 2100 series carb?

I had the same problem with rebuilt carb from Advance Auto. I tried to adjust it and carried it to a old ford mechanic with no luck. I found a shop that used to build ford race engines. There was a warped plate in the carb and it had the wrong float in it from the rebuilder. It runs better that it did when it was new and no gas smell.
 

broncnaz

Bronco Guru
Joined
May 22, 2003
Messages
24,341
Whats your timing set at? if its to far advanced you will get a gas smell. Try turning it back and readjusting the carb. Also where does your exhaust sytem exit?
 
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bannind

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
To be honest I am not sure on the timing, I will have to check tomorrow as the wife already has this evening planned out. The main reason I am wondering about the jets is because whether it is warmed up or been sitting 2 days it will start up immediately and you don't have to even touch the choke.

I pulled the top off and the float looks like it is fine. The jets are 56's I did take off the float and blow some air through it incase there was anything stuck.
 

Bronco Billy

New Member
Joined
Mar 1, 2007
Messages
41
Loc.
Memphis, TN
Is there a chance the choke is not totally pulling off, making it run rich?
Could account for the quick cold start if it stays on.

Can you borrow another carb, swap it and see if there's a change?
 
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bannind

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
manual choke fully open.

I picked up a Motorcraft 2150 from the yard with the tag of E1TE BGA and I am planning on putting a rebuild kit through it on Thursday. Hopefully that will help.
 

muladesigns1

Full Member
Joined
Jun 4, 2007
Messages
166
Loc.
Goodyear AZ
sound like you have the carb adjusted properly, I would check the jetting size. the old muscle cars of the 60's are notorious for this because of (fat jetting)
 
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bannind

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
new jets are what I am looking at doing now.

I am currently running 56's (that is what came with the carb) what jet number should I be moving too? 51's? or even more?

thanks,
dan
 

wildbill

Old Bronco Guy
Joined
Jun 29, 2001
Messages
6,885
;D ;D ;D I would think you should start with a fuel presser regulator as you mite be pushing to much gas and it is leaking by. This would give you the run rich smell good luck.:cool: :cool: :cool: Bill :D :p %)
 

kirkallen143

Jr. Member
Joined
Apr 6, 2004
Messages
102
Loc.
Navasota, Texas
;D ;D ;D I would think you should start with a fuel presser regulator as you mite be pushing to much gas and it is leaking by. This would give you the run rich smell good luck.:cool: :cool: :cool: Bill :D :p %)

That's what I would say first, too much fuel pressure. Is the Carter electric pump made for a non-bypass system or does it need a return? What is the rating of the pump? Can you throw a mech. pump back on there to see if that is your problem? A fuel pressure gauge is easy to install inline and can tell you a whole lot about your fuel system...cheap, too.
If it is too much pressure, it is keeping/forcing the needle open and not letting it shut.

Also, look at your plugs. Black and sooty (rich), white and no color (lean). You want a light brown/tan color on the plugs. What do the inside of your tail pipes look like, is there black soot at the ends?

Let us know.

Kirk
 
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bannind

bannind

Sr. Member
Joined
Mar 24, 2005
Messages
612
The pump is rated at 6psi max. I can not put a mechanical pump back on with the explorer serpentine setup. I can try the regulator thing and I will check the plugs later today once I have a moment to get out and take a peak.

thanks again.
dan
 

kirkallen143

Jr. Member
Joined
Apr 6, 2004
Messages
102
Loc.
Navasota, Texas
Doing a little research for you this morning:

That pump free flows 72gph (gallons per hour) @ 6psi, and is self regulated. This is a high volume, low pressure pump.

This is the formula what your engine needs/requires from a fuel pump at a certain Hp rating:

Fuel Required = (Target Hp) * (BSFC)

BSFC: this is the brake specific fuel consumption, which is the amount of fuel it takes, in pounds, to support 1 Hp for 1 hour for every engine. For a naturally aspirated engine, it is b/tw .45 - .55 (lbs/hr).

In your case we will say you want 200 hp.

FR = 200 * .50 (an average BSFC)
FR = 100 lbs/hr

Now to convert this to gallons/hr just divde by 6, since gasoline weighs about 6 lbs per gallon.

FR = 16.67 gal/hr
< this is what your fuel pump's output needs to be to run your engine properly at 200 Hp>

As you can see the pump you have, which is rated at 72 gal/hr, is 4 times as much fuel that you need. This proves you are getting too much fuel, and the reason for your smell.

By the way, your engine would have to support 4X's the Hp to use this pump. A cheap alternative would be to plumb the mech. pump back in, w/ a fuel pressure gauge, and see where it takes you from there.

Good luck,
Kirk
 

kirkallen143

Jr. Member
Joined
Apr 6, 2004
Messages
102
Loc.
Navasota, Texas
The pump is rated at 6psi max. I can not put a mechanical pump back on with the explorer serpentine setup. I can try the regulator thing and I will check the plugs later today once I have a moment to get out and take a peak.

thanks again.
dan

Dan since you cannot go w/ the mech., I would suggest getting an electric pump more suited for your engine and/or try the pressure regulator.

Did you say that your float level is good and not too high? This is a holley 2-barrel (2300 series)? You said 2100, which is the autolite carb. If it is a holley, you can adjust your float externally w/ a wide flat blade screwdriver and a 5/8" wrench. There is a site plug on the side of the carb and you want the fuel (with engine running) to just trickle out of the hole. If too much comes out or not any at all, you can adjust (with engine off) by turning the nut clockwise to raise float (if level is too low) and counterclockwise to lower float (if level is too high). Each turn of one hex flat of the nut raises/lowers float approximately 1/32" (so a full turn of the nut is about 3/16").

Have you adjusted your idle air/fuel mixture screws? Rule of thumb is 1 1/2 turns out from being fully seated to start. But the best way is w/ a warm engine at idle turn one of the screws in until you hear the rpms fall and then slowly turn out until smoothest rpm range is found. Then do the same on the other screw. Both screws should be the same # of turns out. Then adjust your idle back to the appropriate setting if it has changed.

No external fuel leaks? Do you still have the charcoal canister under the pass. side seat at the frame? Some models had a plastic vapor tank behind a screwed on metal cover inside the body behind the drivers seat. I would check these for leaks and/or broken lines.

Doing more research here it seems some are running the 4070 with no problems. Then again, every engine is different.

Keep us posted.

Kirk
 
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