Starts, but then dies.

[eLtOro]

Bought my first 1978 Datsun 620 King Cab about a month ago. It was a two owner truck 97,000 miles. It had been parked for about three years prior to me buying it. It is nine stock!! After I bought it I went through it changed all the fluids, drained the fuel tank and rebuilt the Hitachi carb. It ran perfect! Until five days ago. Was driving it and it was a little hot out side and it lost power. It would idle fine but when I wwould put it into gear and try to go it would stall out. My first thought was it just got to hot. Got it home and messed around with it some. Two days later when I got off shift I got home and it stared up and ran perfect! Till this morning. She started up just fine and drove about half a block from my house and she started acting up again. No power, she will start up and run for a little bit then die out. I have searched the internet and went through my shop manual. The accelerator pump is working and haven’t noticed any vacuum leaks. I’m leaning towards a clogged idle jet? It really bums me out.

[datzenmike]

The idle jet only controls the idle so if it ran ok or idled ok the idle circuit is probably ok.

 

Next time if craps out look at the glass sight glass in the front of the carb. The gas level should be in the center on the dot. Is it?

 

Pull a plug wire off and put an old plug in the end and lay on a grounded surface. Turn the engine over with the starter. Is there spark???

[Dolomite]

If it was sitting for years, it could be buildup in the fuel tank or filter. Make sure nothing came loose and caused a vacuum leak.

[eLtOro]

A little more, new fuel filter, new plugs. The sight glass on the front of the carb is a little bit over half.

[eLtOro]

I go on shift tomorrow morning and get off Monday. I’ll check that stuff out then! Thank you for your help!

[racerx]

Fuel tank can be dirty.

[KoHeartsGPA]

Grab a bottle of gas, run line from it to the pump, see if it improves, likely a dirty tank, you can also get a clear filter so you can see what's coming in.

[datzenmike]

  Was this checked when the engine quit? or when it was running fine??? Needs to be checked when not running right. This is a randomly occurring problem and needs to be checked when happening.

[banzai510(hainz)]

I run 2 flters on my 521 as the tank is exposed and the fuel line in wheelwell.

 

I would run the shit out of it and try reving up the motor and put a rag over the carb to suck the dirt out. also get soem carb cleaner shoot it down.

To me the main jet is getting plugged. if you push the gas. but let off its the idle jet that uses gas

or the dist is off when it aceellerates

[eLtOro]

Got home this morning and pulled the air cleaner housing off, messed with the choke a little. She started up fine and seems to be running like a dream again. On Friday when I parked it the glass sight glass on the carb was a little over half of the glass. This morning it wasn’t even showing in the glass. I’m going to grab another stock fuel filter and then a inline fuel filter to. Really baffling me...

[banzai510(hainz)]

the needle valve letting gas in the carb might be sticky also.

[Stoffregen Motorsports]

I wonder if your fuel pump is bad, letting the fuel return to the tank. This can happen as pumps get old. It won't affect how your car runs, but it will take more cranking in the morning to get fuel to the carb.

[eLtOro]

Up Date ..... she is running Great.. Fingers crossed she keeps it up. Can’t thank you guys enough for you help!

[racerx]

What was the issues?

[datzenmike]

The lines might siphon back to the tank but it can't empty the carb. There will always be enough gas in a carb to start and drive half a block.

 

 

 

Again you have to check the fuel level when it's not working. This will prove or disprove that it's running out of gas and it's a delivery problem.

[eLtOro]

Not really sure of the fix. I pulled the air cleaner housing off yesterday morning ( 5/14 ), pulled the choke apart and made sure all the vacuum lines that are on the air cleaner housing were free and clear. She started up and ran Great. Put it all back together and adjusted the idle and air mixture replaced the fuel filter.