67S Hesitation under load

[behyar]

My car was having an intermittent starting problem which was fixed by replacing all spark producing parts. It now has a new battery, coil, wires, plug, dist cap and rotor. All these item were very old anyway. It mow starts fine, and I can rev it up normally while in the garage, but when I take it out driving, it hesitates as the revs go up. It feels like its not getting fuel. I can see fuel going in while testing with the air filter out.

The timing seems normal at around 30 BTDC @ 6000 RPM. Its not very steady, but I attribute that to the fact that my mechanic had told before that the distributor has "worn to a 2-stage advance". The points are set at .4 and the spark plugs gaps are at .35

Any hits as to what I should check is appreciated. I am also posting a few pictures of the car.

Thanks,

Behyar

[neilk]

Do you have a fuel pressure guage back there? Perhaps you aren't getting enough fuel to power the car at high RPM or you have junk clogging one of the jets.

I am sure some of the carb experts can chime in. How old is the fuel filter? I know you have carbs, but you should check out Jol's post titled Fuel Filter Woes. You might have a clogged line somewhere.

[Soterik]

Plugged idle jets.......3 screws on top outboard side of carbs.....carefull pulling them out, as they have a little rubber O ring that is very easy to lose. Blow them out, and you should be good to go....unless you have a pile of junk in the fuel tank. Maybe install an inline fuel filter.

Eric
4 67S's

[behyar]

I'll check out the jets. I have an in-line fuel filter. The gas tank may also be suspect since the car sat for 7 years before it was handed down to me. The mechanic who got it running again has supposedly cleared the tank, but he said it was a mess.

[nick-moss]

Just clearing the tank on a car that has sat for 7 years may not be enough. Corrosion causes the paint to flake off the inside and blocks the gauze on the outlet. POR15 do a tank cleaner and sealer kit.

Try cleaning out al the jets and float bowl as well

[gruen911]

Definitely have the tank cleaned and resealed whether that ends up being the problem or not. Nothing worse than getting your carb's sorted out and dialed in and then have a small piece schmutz mess things up. Also, try replacing the fuel lines if you haven't already.
Car looks nice and the engine compartment looks clean. Where are your wipers?

[roblav]

Either plugged idle jets, main jets, or the small transition orifices near the throttle plate. Very typical...

[911pcars]

...." it hesitates as the revs go up...."

Can you elaborate?

Does it run okay at steady high speed?
Does it stumble upon acceleration? If so, any speed?
Any other symptoms?

Sherwood

[behyar]

Sherwood,

The car starts OK and it seems to rev up fine (5k-6K) while standing still and out of gear. But then when I start to drive and go up the gears, it starts to sputter, loss power and momentum. If I feather the throttle, I can get through the sputtering and once I get up to speed, I can maintain it. It is only when I try to accelerate that it shows up, and shows up badly.

The consciences here seem to center around the Webers and fuel which is certainly possible given the long time the car was non operational. The Webers were rebuilt 6 months and 500 miles ago when the car came out of hibernation.

Initially I thought it may be spark related since that was the last thing which was worked on. I also saw some old posts in Pelican where a bad exhaust was causing similar symptoms.

[gruen911]

Having to feather the gas pedal in order to get power above 6k revs leads me to believe that either the carbs are dirty and need rebuilding - again, or that the jetting is wrong. As I stated in my last posting, there seems to be a good chance that the junk that was in your tank is now in your carbs. Could even be water.