Hard to start When Cold

[Datsun660z]

Please help I have A 1976 280z that has been changed to 260z carbs the ones with the flat tops. When it is below 50 degrees outside my car wont start unless I prime the carbs with gas, both chokes come on when I pull the lever back. Please help.

 

Thank You.

Jon

[Kevin Shasteen]

Jon,

 

That is a drivability problem & could be just about anything since the car is not original...only you know its set up best.

 

It could be anything from improper ignition timing to spark plugs/plug wires, coil, carb choke, fuel pump, to a relay that acts up under the stress of the cold(?).

 

Give more details; when it is above 50F after it starts does it spit/sputter or does it ever backfire?

 

When it is below 50F as you turn the engine over is it a slow turn or does the engine turn over fast/normal. If its a fast & even turn it means you have good compression usually & a strong starter.

 

The three things that keeps an internal combustion eng.from running is the lack of:

 

1) Air

2) Fuel

3) Electricity (Ignition)

 

or a combination of the two/three.

 

Your best bet is to obtain a Service Manual & follow the flowchart.

 

I would first confirm your ignitions spark is strong. Confirm the choke mechanism is functioning correctly, & confirm your ignition timing is set properly.

 

I'm no carb specialist but I do have a 260 service manual. If you are having carb prob's then the flow chart for checking the carb is:

 

Trouble Diagnosis:

1)Eng.Does not start

a)Overflow

b)No fuel feed to the engine

c)Improper Idling Adjustment

d)Malfunction of suction piston

 

a)Overflow

* Float Leaking...Replace Carb Assembly

* Dirty Needle valve Seat...Clean Valve Seat

* Loose Needle Valve...Retighten

* Scratches/Worn Needle Vlv.Seat...Refit/Rpl

* Fuel Pump Drawing in Air...Repair Pump

 

b)Nor Fuel Fed to the Engine

* Check Pump for proper operation

* Check Fuel Lines

* Check Needle Valve

 

c)Improper Idling Adjustment

* Readjust appropiriately according to spec's

 

d)Malfunction of Suction Piston

* Sticky due to deformation...Rpl Carb Assem.

* Bent Jet Needle...Rpl Carb Assem.

* Bent Plunger Rod...Rplace

 

As I said earlier...it could be just about anything/hope some of this helped!

 

Kevin,

(Yes, Still an Inliner)