Problems and Questions RE: 1971 Datsun 240Z from Francesco

Posted May 28, 201113 yr

I am the original owner of my 71 240Z. bought new in l971

and I have 2 manuals (Factory Service Engine (FSM) and Haynes. No dealer within 100 miles has a mechanic who knows anything about my car. I am grateful to find a source of fellow owners who may be able to help me.

Ever since I rebuilt the engine, the car runs well over 20mph

but the engine does not start the way it should; is not smooth taking off in 1st gear; and is a little hesitant going into 2nd gear.

PROBLEMS: Before, choke would pull

all the way back; now it only goes about 3/4. Seems can't

adjust cable to allow choke to be pulled all the way back.

Before at 50 degrees temp, I only needed to pull choke about half-way to start. Now I have to pull as far out as possible. Then RPM jumps to 1000-1500 and I have to quickly push choke lever back down some. If pushed too far

down and after a couple of attempts, it will continue running

at 1,000 rpm. If push lever all the way down, it may stall again. When idle seems stable, I have to carefully ease out

in lst gear. It's alittle rough and will stumble if not careful.

If after pushing lever all the way down, I pull it out slightly

it seems to run more smoothly in 1st gear. Increasing idle

to 850 helps some, but not like pulling lever out slightly.

QUESTIONS: 1. When choke lever is pulled out slightly,

(even though change in dimensions "H" is imperceptible) is

more air flowing into the car? 2. Also in regard to fuel, does

pulling lever back (even though change in dimension A is

imperceptible) allow more fuel to enter? 3. Do you think that

increasing or decreasing the interlock valve opening would help? 4. Do you think increasing or decreasing the depth of

the nozzle when choke is all the way forward would help?

5. Coil has some oil in primary terminal--could that be the

problem? Is there a definitive test (on or off car) that would

determine if coil is bad? (Other than OHM resistance test.)?

6. If there is water in the tank. could that be part of the problem? 7. I set carb needle flush with "groove" at base

of piston. Is that correct?

Background: I replaced carb nozzle and needle; clutch

assembly and slave cyclinder; rotor and cap; fuel filter.

Adjusted and reset timing, valve clearances, float (did not

have replacement float filters.) Checked plug wires, points,

condensor and fuel pump. Compression in all cyclinders about

160; plugs grey-brown; aiar intake balanced with flow meter.

On carb,set space between bridge and nozzle at about 2mm;

interlock valve opening at about .060mm (FSM dimensions,A & H pp.EF 24, 25) With choke lever pulled out completely,

nozzle depth is about 9mm. If apply pressure to top of nozzle, it will depress aabout another 3mm. Mileage before

rebuild about 80,000; driven 1500 since. Car sits outside in

winter for about 5 months.

THANKS FOR TAKING THE TIME TO READ ALL OF THIS! I

have been struggling with this situation for 2 summers and

any advice will be greatly appreciated! All the best- Francesco