Okay, what's going on? (Edelbrock 1406 troubles)

[shuttermutt]

I finally put the choke cap on the Edelbrock 1406 that I rebuilt. All is well. The choke works great and I don't have to feather the throttle to keep 'er running when she's cold. It takes the RPM's kind of high for my taste (over 2,000 rpm almost instantly), but it'll do for the moment.

What's annoying, however, is that before I've got two other strange problems that don't have anything at all to do with the choke. I'm pretty sure, anyway, since the truck does the exact same thing with or without the choke wired open. The problems are:

• For no damn good reason, every so often the idle will change. One time when I hop in the truck it will purr at 800 in Park and 650 in gear. Then shut 'er off, run into a store for a Coke, come back out and it will suddenly not want to idle and, when it does, the idle is only 450 or so RPM.
• When the engine's warm, I've got to crank it far too much and mash the throttle for it to start.

Now, on the second item, my timing is advanced, but not so much so that it should be causing hard warm starts. I'm wondering if my secondaries aren't shutting all the way (or taking a long time to do so). For example, I drove the truck in to work this morning and it ran like it had fuel injection. Today at lunch, however, it started off fine, but then it had both problems listed above after I came out of the restaurant about 10 minutes after running it up to full operating temperature on the highway -AND- opening the secondaries for the first time all day.

The only other thing I can think of is that, for some reason, the carb is continuing to deliver fuel down the intake after I shut the engine off. I'm not sure what would cause that exactly, but it does act like it's very, very lightly flooded when I jump back in sometimes after it's been driven up to temperature for a while.

I'm just about to hop in and go home. It's been sitting for 5 hours so it's nice and cool now. I'll reply to this thread with details on how it acted when I get to the house. Any tips or suggestions are welcome. Any Edelbrock carb experts coming to the Minnesota board meet?

[cableguy0]

yea mine used to do that too till i permanently fixed it with a 4160 holley. edelbrocks in my experience are buggy the carb design is great on paper but in the real world i havent had much luck with em.i know this probably wasnt much help. but it kinda sounds like the fuel is boiling out of the carb. try a 1 inch spacer to get the carb away from the intake. also on your idle speed problem you might need a tighter spring for the throttle return it may not be closing it all the way when you are trying to tune it and by chance it closes all the way sometimes and ur idle drops

[TugOwar]

I just got a 1406 finally running half way smooth after it had sit for 3 years, I thought I'd never get all the trash out of it! You just rebuilt yours so trash or worn parts shouldn't be an issue.

Mine does the same idle thing, perfect one time and low the next, don't know what causes it. Maybe just an edelbrock thing.

About the choke idle, mine was kickin up about 2500 when I first hooked up the choke, kinda scary on a cold start ya know. On the opposite side from the choke, roll the throttle all the way back and you'll see a screw under there, that is the fast idle screw for the choke. Kinda difficult to get to alone but it can be done. I turned mine way down, seldom need the choke around here anyway.

Good luck.

[rage'nrat638]

i got one that does the same stuff......
but i only payed 50.00 for it....

and i got a edelbrock intake...too.....

so now what.......live with it...i guess....

[walker]

Get that insulated spacer, wood or phenolic, that will keep the fuel from boiling out of the carb when it is hot. That cured alot of my troubles with that carb. Might try adjusting the fast idle cam to get the RPM down. Also might try your vaccum advance on the port opposite of the one you are using now. I fiddled with it for a while trying to perfect its tuning. It took some experimentation, but it is running great now. I also played with the idle mixture screws alot during this process. Also, I used a vaccum guage during most of this process, it was educational.
Good luck, Andy.

[shuttermutt]

Good to know I'm not the only one. I'll set the choke sometime this week and look into a spacer as well. Thanks for the responses!

[rage'nrat638]

i just ordered a phoniloic spacer from summit....39.00 shipped

hope this works....it's got to help....

[shuttermutt]

Originally Posted by rage'nrat638

i just ordered a phoniloic spacer from summit....39.00 shipped

$39 for a spacer!?! Damn, for that money it had better come with a bikini clad model to hand me cold beer while I put it on!

[cduster]

Sounds like the spacer would help. I had the same kind of problem and the spacer seems to have cleared it up. Another thought is that your throttle plate is open a little bit. Did the butterflys move freely during your rebuild?

[oldsub86]

Are the floats set at the right height? I had a similar problem with a brand new carb out of the box (the hard starting when warm bit - not the up and down idle).Tuning didn't seem to help and I lifted the top off to find the floats were way out of whack. Setting them down to the recommended height helped a lot. I also put a spacer in. I still think it runs rich but I have not gone to the point of changing jets etc. I think that is next but it is on a vehicle that I am not currently driving so it is waiting for me.

[da-burb]

Your gas is boiling in the carb. I had it on my first 1406. Went to the insulated spacer and it all went away. I have 2 carbs in operation and have had no other problems. They have been the least trouble of all the carbs.

[shuttermutt]

Well, I'm gonna order a spacer and see if that clears it up. Aside from that, the carb has been 100% trouble free since I rebuilt it. It's kinda hard to keep my foot out of it, though!

PS: You coming on Saturday, 'Burb?

[Longhorn Man]

It is boiling...a mild form of vapor lock.
The spacer should help, but there are other things to do too.

If your fuel line is touching the engine at any point, move it.

Route the fuel line so you have 1 inch minimum space between the line and engine.

Keep fuel lines away from exhaust...as far as you can. If you can't get it far, protect the fuel line with a heat shield/wrap of sorts.

If the exhaust is real close to the frame, see if it is heating the frame, and maybe transfering it to the fuel line.

If there is a fuel filter between the tank and pump, remove it and install a line/hose in its place. The filter should only be on the pressure side of the line, which would be between the pump and carb. Reducing the pressure lowers the boiling point, and even a clean filter will drop the pressure a bit, let alone a clogged one. Place the filter on the other side of the pump, and the oposite happens, the restriction causes a fuel pressure increase, and therefor raises the boiling point.

I have also found that a 160 degree T-stat helps quite a bit too...esp in the hot months

The reason your RPMs drop, is that the vapors are all that is being fed into your engine at that particular moment. Then when a pubble of fuel makes it to the jets, teh RPMs jump to the proper speed.

[valk_ryder]

Yep, you need the insulating gasket. Both my SBC 350's with the 1406 are hard to start hot. My friend with the same setup and an insulating gasket has no starting trouble ever. Also, the pink metering rod springs really helped both of my carbs and also my friends. Great carbs.

[shuttermutt]

Yeah, the floats are set to Edelbrock's latest specs and the butterflies are moving as they should. The fuel line is routed carefully so I don't see that as an issue. I've got the pink springs in, too. I'm keeping my fingers crossed that a spacer will clear it up. I'll keep everyone posted.

[flip66]

just want to keep up with the thread.

[SweetandLong68]

I don't know if this is the problem on yours but Eldelbrock carbs dont like alot of fuel pressure. You need to run a pressure regulator right before the carb to keep the pressure down. Around 4-5 psi usually works. Holleys like alot more pressure so if you changed from a Holley then that could be the problem.

lata
CHRIS

[da-burb]

Ditto on the fuel pressure.

I am going to try to make it. I am currently working in Nevada (ne-VAY-da) Iowa and hope to be done by Friday afternoon. If not, I will be driving back on Saturday. If I can make it, what should I bring? The burb or the motorhome?

[shuttermutt]

Just a follow-up... During the Minnesota board meet on Saturday, Todd, Mike and I hung a new set of plugs (thanks for the helping hand, guys!), tweaked the IMS screws and gave 'er a bit more advance. Now it's pulling about 18 lbs (up by a few pounds) at an 800 rpm idle and definately picked up some power.

On Sunday I played with carb spacers. Much to my surprise, I got the biggest "seat of the pants" gain with a 2-inch tall, 4-hole, phenolic spacer from Edelbrock. It's more responsive through the entire rpm range that I drive in most of the time (idle through 3500). On the other hand, the 1-inch spacer (also Edelbrock) didn't seem to make any real difference at all.

Best of all, my hot start and idle problems are completely solved. I can run it hard and hot, kill the engine for 2 minutes or 2 hours, hop back in and she fires up with barely more than a bump on the starter and without putting my foot anywhere near the gas pedal. No more of that nasty cranking you heard Sunday, Todd!

The idle now sticks right at 800 rpm in Park and 650 rpm in Drive. I don't have any idle fluctuation, the response is as crisp as it's gonna get no matter how hard I hit the gas or at what rpm and, well... everything works. I did end up with a spacer since I use a drop-base air cleaner and a 4-inch K&N filter. Basically, it's like this from top-to-bottom:

• air cleaner lid
• 4-inch K&N filter
• drop-base air cleaner bottom
• 2-1/2 inch spacer
• carb
• 2-inch, 4-hole, phenolic spacer
• Edelbrock Performer RPM intake

It all fits under there, but there's not much room for anything else. Now that I've found a combo that works for this particular engine, I'm sticking with it. Thanks to everyone that offered up their suggestions!