Edelbrock rod and jet change-By Joe, I think she's fixed !

[BNC04]

I'm going to be changing out the jets and rods on the 1405 I'm running at the moment. The truck is running a little rich and was tuned for lower elevation ( Oklahoma). I have .095 jets and .065 x.047 rods that I found by searching here a few weeks ago. Also have the offroad needle and seats to install. I'll check the float setting as well. Is there any words of advice before I do this?

Thanks
Brett

[71 Broncman]

Walk in the park, if you do it on the engine put a wrag in the butterlies in case you drop something. 20 minute job.

X2. I did mine right out of the box before I installed it. Pretty easy and it works great.
Mark.

[Shawns Fords]

In the old days when the Carter AFB Carburetor was a hot item you could walk into a super shops and buy a "strip kit" for 20 bucks with an assortment of jets, rods and springs it was a good reason to see how much fuel/rubber you could burn in a weekend. Now I believe an Edelbrock strip kit will run around 65-75 bucks and everything is in individual boxes to pick and choose from.
I got tired of dealing with "flat spots" and went back to a holley.

[BNC04]

Thanks guys. for some reason carbs just do not like me.
Carb is a 1405
primary and secondary 1426 jets
rods 1445
Offroad needle and seats

The swap was really easy. I cleaned it up real well at the same time. Adjusted the floats to 7/16" and the drop to 1 1/4" per a writeup up for off road fixes. Also plugged the rear valley with tubing to prevent sloshing in off camber situation.
http://www.pirate4x4.com/forum/showthre ... rra+nevada


But.. Alas,, I took it for a spin and didn't really notice much difference and was maybe worse, the idle was rougher and it was not as responsive as I'd like so I started to adjust the A/F screws and idle per the instructions and was not getting anywhere before I called it a night last night.

Hard starting, bogs very bad off idle it stabbing it, but will rev up on on slow throttle application.

I'm going to hook the vacuum gauge up this afternoon and baseline the A/F screws at 4 turns out from seated and see what I can do that way.

Brett

[BNC04]

Thanks
I've messed with the adjustments so much now that I need to re-baseline and then I'll give that a try.

Brett

[akaFrankCastle]

Brett, what are you running your timing at right now?

[BNC04]

Brett, what are you running your timing at right now?

Sorry to say, I don't know and don't have a timing light. ( yet )

Brett

[akaFrankCastle]

Gotcha. Big recommendation to pick up a timing light. In the interim, try hooking up that vacuum gauge and adjusting your timing until you pull max vacuum with pinging. Take it out for a test run and continue to advance or retard the timing until you get the throttle response you are looking for. Zoso gave me the same advice and it worked out great.

[BNC04]

Gotcha. Big recommendation to pick up a timing light. In the interim, try hooking up that vacuum gauge and adjusting your timing until you pull max vacuum with pinging. Take it out for a test run and continue to advance or retard the timing until you get the throttle response you are looking for. Zoso gave me the same advice and it worked out great.

Did you leave your dizzy vacuum line attached and pulled vacuum off a free carb port?
Thanks


And yes, I'll be getting a light sometime soon.

[akaFrankCastle]

Yup. Pulled vacuum advance line from the carb and capped it. Then ran the vacuum gauge to a port pulling vacuum at idle.

[BNC04]

I got a chance at lunch to do some work on it.

Took the airhorn off again and re-adjusted the drop of the float to 1" vs what the article said ( 1 1/4") .
Set A/F screws . backed off 1 3/4 turns from seated.
Had a heck of a time getting it to run, finally was able to get it to idle. Still stumbles very badly regardless of which hole the accelerator pump is in. ( was in middle) checked and played with dist using vacuum as a gauge. It was set at max vacuum already so no changes made there.

I have to give it quite a bit of pedal before it will fire and I Don't have a tach yet either but the only way it will idle is is I have it set higher than I would like.
I can smell gas , does this sound like it might be flooding still and I need to reduce the float even less than 1" ?
or should I play with the A/F screws some more to try and adjust it leaner ?

Thanks for all the help guys.


Before I changed the stuff on the carb, It ran decent, Started right up, idled well.
There is an "RV Cam" in it if that makes a difference. Comp cam.

Brett

[BNC04]

Played with it some more.

Got it to fire and idle. moderate stabbing of the pedal seems to do ok. quick stab of the pedal- hesitation.

I was just out looking again 10 mins after I shut it down and I see fuel dribbling/ dripping at at one point, a steady dribble from the venturi down into the carb. Also noticed the vertical venturi tube, bubbling a slight amount of fuel from it.

I do have a elec fuel pump, could this just be residual pressure from that?

I have 2 inline filters I will be replacing after I can get to the store as well to take that out of the equation.

Brett

[akaFrankCastle]

I got a chance at lunch to do some work on it.

Took the airhorn off again and re-adjusted the drop of the float to 1" vs what the article said ( 1 1/4") .
Set A/F screws . backed off 1 3/4 turns from seated.
Had a heck of a time getting it to run, finally was able to get it to idle. Still stumbles very badly regardless of which hole the accelerator pump is in. ( was in middle) checked and played with dist using vacuum as a gauge. It was set at max vacuum already so no changes made there.

I have to give it quite a bit of pedal before it will fire and I Don't have a tach yet either but the only way it will idle is is I have it set higher than I would like.
I can smell gas , does this sound like it might be flooding still and I need to reduce the float even less than 1" ?
or should I play with the A/F screws some more to try and adjust it leaner ?

Thanks for all the help guys.


Before I changed the stuff on the carb, It ran decent, Started right up, idled well.
There is an "RV Cam" in it if that makes a difference. Comp cam.

Brett

Brett, sounds a lot like a timing issue to me.

Reducing your hanging float measurement only changes the level of fuel required left in the bowl before the needles open and begin refueling the bowls. Flipping the carb top and changing the distance on the floats changes when the fuel is cut off to filling the bowls. Think of it as changing your float in your gas tank. Decreasing the 1-1/4" tells you on the fuel gauge that you are nearer to empty than what you truly are. That being said, I'd change your drop back to 1-1/4"

Set your mixture needles back to 2 turns or so and loosen the bolt that holds down the dizzy, just enough so you can turn it by hand. With that vacuum gauge hooked up, slowly turn the dizzy til you peak on vacuum then lock it down.

What type of electric fuel pump are you running? Any idea what PSI it is putting out? Carbs like between 5-7PSI IIRC.

Check your fuel lines and make sure none of them are running too close to any heat sources.

[ZOSO]

Just what Zach said. Sounds a lot like timing. Go pick up a timing light. My carb was the exact same way. once I "tuned" it the thing was hard to start. Put about 12* timing into it and it fires right up.

The gas you see is cause the gas in the carb is boiling from heat soak. a thing that helps with that is a phenolic carb spacer to keep the carb isolated from the manifold heat. You can tune it all up with just a vacuum gauge. Some slow reving and rough running can be greatly affected by ignition timing.

[ZOSO]

Also post up what you took out. I have a spreadsheet that I can plug all the info in to tell you the % of change.

[BNC04]

Thanks all,, Mr AKAFrank Castle wins

I took the carb off the manifold because there was some fine dirt in the bottom of the bowl. While I did that, it all got cleaned and taken apart. Validated the needles and seats and floats were working as designed, checked the pump shat, etc etc etc. Put it all back together, set A/F screws 1 3/4 turs off seating depth.
Same issue.
Set up the vacuum gauge, and started turning the dizzy. turned it left a bit and it woke right up. Very responsive and back to normal. Still a tad rich maybe but I'll check plugs in a day or so to validate.

Went for a spin to get some , and it started sputtering and died. The carb gasket did not want to be re-used it seems so I'll replace that tomorrow. It's leaking fuel around the base, and I'm sure a huge vacuum leak as well.

Thanks for all the help, and I appreciate you shortening my learning curve. Carbs always seem to get the best of me when I try to mess with them..

Zoso,, it was a stock .100 jet and .070X.047 needle. I might be one step too lean but we'll see what happens over the next little while and I'll check plugs soon.


Brett

[ZOSO]

a little trick for the new gasket is wipe a thin layer of grease on both sides before you put it on. It will act like a sealer but allow you to remove the gasket later if need be.

Once I get my tuning laptop back this week i'll get that % for you. I bet you need to put the 070x047 needle back in to lean it out a touch. You kept the same size cruise step and went down on power step only. Try that if you feel it's running too rich.

[BNC04]

Thanks for that tip.
i'll check the plugs after I get to drive it some.

Brett

[BNC04]

update-

yesterday I was able to get the idle and response doing really well. Took it for a short run and after about a mile , it started bogging missing, loading up.. Not sure how to describe it,, Basically like a bad vacuum leak. I thought since I just reused the old manifold to carb seal, it did not seal well and that was where the leak was since I could also see gas dripping onto the manifold in that area.

Went to the parts store today, picked up a gasket and put that on today. Started it up at lunch, Set timing again. idles really well, very responsive.
After work, I took it for another spin, Again after about a mile, it does the same thing as yesterday and fuel is dripping from under the carb, right at about the throttle rod goes into the carb. Also fuel is just pouring into the primary's. There is a blag plug looking thing just to the rear of the throttle rod that goes into the carb, it "seems" maybe to be leaking from there. I think it may also be leaking from that same general area on the other side of the carb also but not as bad.

I'll try and get a couple pics up in a little bit to show what I am trying to describe.




the area that it seams to be leaking from is at or just below that black plug.. I tried to get it to unscrew but it wouldn't


all of this started after replacing the needles, seats and jets.

Thanks
Brett

[BNC04]

Played with it a bit more, Now I think the FP is too high for the new needles and seats and float adjustment, Off to get a pressure gauge and regulator to plumb into the line tomorrow.. I am DONE for today.

Brett

[akaFrankCastle]

Brett,
Looking at your pics I think the empty hole you see on my 1405 is where the black plug is on yours. If that is the case, the only thing that runs through that hole is the pivot bar for the secondary butterflies. Chances are, if there is fuel seeping out of that hole, it is coming from inside the carb, onto that bar, and running out the hole. But there are no fuel channels that run through that area.



I'd have a look at the brass seatings around the carb, such as the one shown below. Maybe one of these has worked its way loose?



Did you put a new gasket in the top plate when you put your new needles and seats in?

Sorry for the crappy iPhone pics.

[BNC04]

I'll check that brass plug tomorrow. Your right, that hole is empty, mine is plugged.
I replaced the airhorn gasket today.

I'm thinking FP because I shut off the pump and it ran much better until it ran out of fuel,, of course it had cooled down by then as well so we'll see. what happens tomorrow.

Thanks again
Brett

[akaFrankCastle]

What pump are you running on it?

[BNC04]

Well well well,, Looks like excessive FP was the culprit. After installing a regulator and setting it o 5 lbs. I put about 5 miles on it, good acceleration, no flooding, and when I got home, no fuel pouring out of the carb and into the venturi's.

Akafrankcastle, The FP is a Mr gasket brand but I cant tell what pressure it is and it's in a not too easy place to reach to pull and look at it.

So thanks again, for all the help and bearing with some basic questions.

Brett

[ZOSO]

Now that you have the adjustable regulator on there a trick to use when you go wheelin and bouncing around in the rough stuff, turn your FP down to 2psi or so.

[BNC04]

ya, killed two birds with one stone there.

I'm getting some backfiring through the exhaust when I let up after a high RPM run so I might back the timing off a tad.

Timing light this weekend for sure.

Brett