No power at high(er) speed

[Walker]

I have a 72 S3 with a 2.25 petrol engine, rebuilt within the last 8k miles. Petronix in a stock dizzy, Rochester carb. Currently set a 7 deg btdc. Gas usage sucks, doesn't overheat. Push on gas at higher rpms and . . . . . nothing. Ease off gas and it picks up speed, except goingup-hill. Any suggestions would be appreciated.

Art

[kevkon]

Art, did you check the mechanical advance in the distributor? The Lucas design is prone to getting stuck since it's out of sight and reach and can get gummed up or rusty.

[Walker]

Haven't visually checked it underneath, but have done the 'suck on the tube' test and the plate does move. I'll pull it apart and see what's there. Thanks.

Art

[4flattires]

Rochester carb...Gas usage sucks,

To be expected, however how bad is sucks? 10mpg? 15? Did it suddenly dive, or are you comparing to another ride.

Push on gas at higher rpms and . . . . . nothing.

Your probably already fully advanced. Check with a timing light as to when (what RPM) you fully advance. Compare to your road test, not by guesstimating, but real MPH. No tach? String your Dwell/RPM gauge in through the vents. No vents? Heck, your not driving a Rover

Ease off gas and it picks up speed, except goingup-hill.

Sure sounds like a classic fuel starvation. Rochesters are super simple to pull apart, clean, reassemble. Sample rebuild page from a Google search.

http://www.classictrucks.com/tech/0802ct_rochester_carburetor_rebuild/carburetor_taken_apart.html