Holley 3310 running rich --- help?

[MikeWire]

Hi all, I have a Holley 3310 and it is running rich at idle and at throttle. It came to me from a '71 with an FE390 in it, and I coupled it up with an Eddy 390 performer intake.

Now when it's running, it runs too rich and I have rich black smoke at idle and when on the throttle - even leaning the idle mix down didn't help. I learned that the 3310 comes stock with #72 jets, so I picked up #70 and #69 jets (elev. here is 3000 ft or so) and popped the side bowl off to find #66 jets in it!?

So, what do I do now guys? How can I lean out the carb? Do I put the #70 jets in and tune it from there or leave the #66?

 

[surewhynot]

First, check the float levels. If they are too high, it could be dumping gas straight down the venturies. If that doesn't help, you can try going down to a smaller jet than the 66, maybe a 64 and see what happens.

Is your ignition system in good shape? If it has a weak spark, it will seem that the carb is too rich.

 

[MikeWire]

Damn that was fast

Well it's a fresh rebuild, with a new dizzy and plugs, but old coil and wires. Seems to run strong, and ran fine with the 2bbl (not rich at least).

I did check the float levels through the peep hole on the side and it was just to the top of the hole, which should be correct right?

I hate to run too lean and burn up the pistons..eek...but a #66 seems too lean to me?

I am running the dizzy vac line to the side vac line on the 3310 - is that correct or should I run it to the base plate vac line?

I am going to find a vac gauge today as well to help with the A/F tune.

 

[fordrka1975]

Might be a blown power valve.

 

[MikeWire]

Might be a blown power valve.

Awesome - I just picked a 5.5 up and I'll swap it out and put the #70 jets in. Thanks guys!

 

[TexasRho83]

I did check the float levels through the peep hole on the side and it was just to the top of the hole, which should be correct right?

Noob question: isn't the level supposed to be hovering just at the bottom of the peep hole?

 

[MikeWire]

Uh, ya I'm dumb...i mean the fuel level was at the bottom of the peep hole. Thanks for noticing that!

Oh edit: I installed a new power valve and new #70 jets tonight and all new gaskets. I'll have time to fire it up this weekend - thanks for all the suggestions guys.

 

[surewhynot]

Good deal. Let us know how it goes.

 

[miottimouse]

i would dump the holly and get an edelbrock double the carb and 1/2 the gas after a mechanic buddy of mine finaly talked me into trying one i was totaly happy with the driveability,simplicity,and reliability of these units and scraped all my hollys to the shelf but thats the 1st thing i would look at is the power valve and the spring for the secondaries [they have being known the get weak]regurds joe

 

[TexasRho83]

I've had both Holley and Edelbrock and have to say the Holleys are a tad easier to adjust.

 

[TexasNomad]

If your Holley is old your going to start having rich issue with me..
There are so many things on a Holley that can go out of tune.. Number on thing is Power valve, jets Idle mix, gummed up Air bleeds, ect..
If you really want to keep your Holley I highly suggest getting this DVD
http://boxwrench.3dcartstores.com/Holley-Install-Tuning-DVD_p_0-12.html
If it can be tuned on a Holley this will show you the right way of doing it step by step..

 

[MikeWire]

Thanks for the info and posts guys. In response, I don't want to ditch the Holley, mainly because it was given to me, but also because I think I can get it to work fine with a little tuning. I also really like the idea of the tuning video, and I may just end up doing that, or taking it to someone who can tune it for me, if I can't get it right.

Well, here's some more info. I got the truck running again with #70 jets and a new 5.5 power valve and new bowl and metering block gaskets. I set the idle to ~1K and screwed the idle jets 3/4 turn from the seat and then was able to set the timing to 14 ATDC - I also adjusted the float level to almost as low as possible, just to eliminate the possibility that it was dumping extra fuel.

There was a little hesitation and some backfiring around 1500 RPMs, so I then backed the idle jets out about 1/4 turn and dropped the idle to 800 RPMs, and it settled down, with no backfiring or hesitation.

It seems to idle cleanly now, but still is a little rich on acceleration - I see some fuel smoke after a couple of good revs up to 4K. After I give it some revs, it also then then idles a little rich, but not as much as before. I pulled the #1 plug and it was black from running rich.

New plugs, dizzy, and ignition box. I am using the original coil and wires it came with...could this be causing a problem by not burning clean enough?

Any suggestions on how to lean it out a little more?

 

[TexasNomad]

Thanks for the info and posts guys. In response, I don't want to ditch the Holley, mainly because it was given to me, but also because I think I can get it to work fine with a little tuning. I also really like the idea of the tuning video, and I may just end up doing that, or taking it to someone who can tune it for me, if I can't get it right.

Well, here's some more info. I got the truck running again with #70 jets and a new 5.5 power valve and new bowl and metering block gaskets. I set the idle to ~1K and screwed the idle jets 3/4 turn from the seat and then was able to set the timing to 14 ATDC - I also adjusted the float level to almost as low as possible, just to eliminate the possibility that it was dumping extra fuel.

There was a little hesitation and some backfiring around 1500 RPMs, so I then backed the idle jets out about 1/4 turn and dropped the idle to 800 RPMs, and it settled down, with no backfiring or hesitation.

It seems to idle cleanly now, but still is a little rich on acceleration - I see some fuel smoke after a couple of good revs up to 4K. After I give it some revs, it also then then idles a little rich, but not as much as before. I pulled the #1 plug and it was black from running rich.

New plugs, dizzy, and ignition box. I am using the original coil and wires it came with...could this be causing a problem by not burning clean enough?

Any suggestions on how to lean it out a little more?

Well if you can't learn it out by using the idle mixtures and there is no vac leaks flooding clogged air bleeds ect. I would drop a jet size..
But remember if your going to change jets all ways go 2 sizes down, seems to be a rule of thumb when jetting Holley's.

 

[surewhynot]

I would at least put your #66 jets back in. You stepped up 4 sizes from where you were and it was rich then.

 

[MikeWire]

I would normally agree, but with the #70 jets it seems to be running less rich than it was with #66 jets. I would also think #66 would run too lean, especially in the winter - we are at ~3000 feet above sea level here. In the mountains it can run well up into 4-5k feet.

The only problem seems to be it running a little rich after getting on the RPMs - if I can get that fixed, I think it will be dialed in pretty well.

How's my timing @ 14 ATDC? Is that about right? It's a stock cam. Also, I mentioned the coil and wires in my last post - would that be giving me trouble - as in not a hot enough spark?

 

[TexasNomad]

Yeah a bad coil can give you some issues I say change it it sure can't hurt any thing.
If that doesn't help then the only real way to learn the carb out is to rejet it.

 

[MikeWire]

Yeah a bad coil can give you some issues I say change it it sure can't hurt any thing.
If that doesn't help then the only real way to learn the carb out is to rejet it.

Maybe I should just get a new coil and wires to be sure. They are all old anyway.

What's should the timing be set at?

 

[surewhynot]

Is it running rich after a road test? Just revving it a few times will cause it to be a bit rich. You are adding extra fuel from the accelerator pump every time you hit the gas.

When you set the idle mixture, how did you do it? The best way is to set it to the point where you have the highest manifold vacuum. If you don't have a vac gage, then you can do it by ear, looking and listening for the highest idle.

The best method I've ever used to tune a holley-

After setting the idle mixture and float levels.

Start with a fresh set of plugs. Drive around normally for a few miles, making sure engine gets up to operating temperature. Pull the plugs and have a look at them. They should be light gold. If black, see if it's dry from too much fuel or wet from oil combustion. If it's dry black, the carb is too rich. If the carb is in good working order, then that calls for a decrease in jet sizes.


It's harder to tune the secondary metering due to the vacuum secondaries. A road test, while doing some hard driving, making the secondaries open is necessary. Then you can read the plugs again and decide if you need to change the secondary metering plate, or jets.



If the engine burns oil, or the carb isn't in great condition, it will be hard to get it right.

 

[surewhynot]

Maybe I should just get a new coil and wires to be sure. They are all old anyway.

What's should the timing be set at?

If it doesn't ping, 14* is ok. I think stock called for about 8-10, but bumping up gives more power to a point. Also remember, that if the rubber has shifted any in the ring on the balancer, it may not be a true 14*.

 

[MikeWire]

Great advice. All the work was done with it in my driveway, and not on the road.

The plugs were a dry black, and new, but haven't been cleaned or replaced since I have been messing with the first original 2bbl I had on it. I pretty much slapped a new 4bbl intake and this used carb I got for free on it to see how it worked (or IF).

I just need to get it out on the road. I took it off insurance because it was just sitting too long, and wasn't running very well at all. Now that it is running well, I'll add it back and take it out.

Just remember this is a fresh rebuild...I think I posted the link earlier in the thread if anyone is interested. I documented and have a ton of pictures.