Gmont

My '66 327/300 does not respond when I stomp on accelerator. It has new fuel pump, gas filter, new carb, new wires, plugs, points, rotor, condenser, dist cap, dist vac advance, coil and even replaced power control valve in Holley after it backfired a few weeks ago. The plug gap has been checked a couple of times (.035) and the points are at .030 dwell, timing set to 6 BTDC, carb adjusted and gas tank emptied. The battery is old but has been checked and is supposedly good. It doesn't just hesitate, it almost stalls when it is loaded up. I'm at a loss as to the problem.

JohnZ

Which carb? What fuel filter? 67's didn't have an external fuel filter.

RK-TECT

It could be several things, but I would check the accelerator pump first. It is inexpensive to replace and would be the first place I would look for the problem you describe. You might also need a larger accelerator nozzle to squirt more fuel into the carb when you punch the gas peddle.

Roger

Gmont

Holley carb P/N 0-80457SA (electric choke). In-line fuel filter F3311DL was installed new when carb and fuel pump were installed. I know the originals 66's only had the screen filter inside the carb, but everyone I have ever talked to said to install an in-line filter.

Gmont

Since the carb is new, I would think the accel pump would be good. When I rev it up in neutral, it seems to respond pretty well, although it did backfire once. It is a lot worse when in gear and under a load.

Nowhere Man

Is this the reason you put on all those new parts? Did you check the springs and weights in the dizzy.

Gmont

The carb and fuel pump were bad and I was told the carb warranty wouldn't be any good if I didn't install the filter, which I believe is needed with the Holleys. The ignition items were an attempt to resolve the performance problems mentioned. If the dizzy is the distributor, I did not do anything with them. I wouldn't know what or how to check them.

Nowhere Man

They are under the cap and rotor. Make sure the springs are not broken and twist the weight it should come right back to where they were what was wrong with the old 3810 Holley? And inline fuel filters are over kill and a waist. Unless your pick up in tank the sock is not there. Have you checked your fuel pressure? Just becouse it's new doesn't mean it's any good

JohnZ

Assuming that the new carb is adjusted properly "out of the box" isn't always a good idea; I'd check and adjust the float levels, and definitely check the accelerator pump adjustment, which many folks do wrong. That .015" clearance check is done with the throttle held at full wide-open position, the lever on the pump depressed, and the adjusting bolt set to achieve .015" clearance between the end of the bolt and the actuating arm on the linkage. This adjustment MUST be done correctly so you get an instantaneous pump shot with the slightest motion of the linkage.

Gmont

The springs are not broken and the weights spring back. I thot you were talking about a way to measure the spring tension. The 327 had a 4160 carb. It was leaking and I could never get the o- rings in the tube connecting the front and rear bowls to properly seat, plus getting someone to work on a carb anymore isn't easy. Regardless I thot it would be better & as low cost if I just replaced it. I haven't checked fuel pressure but it's a good idea. I don't have a gauge but will try to get it checked. Some fuel does remain in the inline filter when I rev engine.

Gmont

I have set the float levels and adjusted air jets on side of carb, but haven't checked accel pump clearance. Will give it a shot. Thanks.

SupremeDeluxe

I got a new 3660 out of the box this year that had the accel pump adjusted all wrong, causing this problem. The spring was at near full extenstion. On snaping the throttle, there was a lean stumble as the linkage movement was compressing the spring for part of its travel; after which it would move the pump and yield a partial shot.

Nowhere Man

The 3810 is a model 4160. The 3810 is the "list" number and used original. If that was indeed original to the car it would have been well worth it to have it restored and rebuilt by someone who knows what they are doing.

Gmont

Yeah, I still have the old orig carb.
As I understand the adjustment,
1. Hold linkage wide open.
2. Gap .015 clearance between bolt head and lever to pump.

Gary's '66

Are the secondaries operating ok?

DansYellow66

I read where you emptied the gas tank. What did that look like - any rust, sludge, or other crap come out? Could be a clogged up sock. If rusted you would probably see that in the fuel filter however. Running the fuel pump pressure test as suggested might reveal something.

You might try temporarily bumping up the timing to 8 or 10 deg to see if that makes any difference. Could be something mechanical like a worn/jumped timing chain or slipped balancer ring although I'm not sure the symptoms match up since it sounds like it starts, idles and revs in nuetral OK.

Gmont

They were, but will check again. Thanks

Gmont

We tried tried that and it didn't help. Seemed best around 6 deg. It does still backfire thru carb when revved hi.

RK-TECT

Gmont, I had a similar problem and solved it with a larger nozzle (squirter) for the accelerator pump shot -AND- by advancing the timing. My carb is an Edelbrock, so I'm not sure if the pump nozzle is easily replaced with a larger one, but I assume it is similar. The size is usually marked on the nozzle, so you can get one that is one or two sizes larger. There is also a linkage adjustment on the Edelbrock carb that provides 3 settings for the pump shot. Again, I am not familiar with the Holley carb, but I'm sure JohnZ can assist you with that!

steampunk c1

Check TDC to confrim your timiing is ok if your marks are off you may be late in timing. Or just try advancing to 10 or 12 degres. Also check vacum and post resault.