510 vs. 620 Hitachi carb.

[Rockatansky620]

I found a rebuilt carb on eBay, and it says its a Hitachi for a 510 but strikes an uncanny resemblance to the factory Hitachi carb on my 620. A re these interchangeable?

 

http://www.ebay.com/itm/130590111478?item=130590111478&viewitem=&vxp=mtr#ht_3618wt_1185

 

Looks like a rocking price and the seller has great feedback. This would save me the time of learning the innerworkings of a cab and let me rebuild my current one in my own time.

[datzenmike]

They are all roughly similar looking, yes. The first electric chokes were on the '72 model but made June '71 so the description is sort of right. The one shown is consistent with the '72 L16 carb. This one would not fit the 620 exactly because of the different throttle linkage. It would also be jetted for a smaller L16.

[DanielC]

A 510 has a linkage that rotates, that goes to the firewall, I believe. If the 620 os like a 521, the 620 is cable operated.

[datsunaholic]

His 620 is a '73, which also used a L16 so the jetting wouldn't be that far off if at all. They're the same model carb, with a minor smog setup change and different linkage (that is easily swapped over).

[datzenmike]

Somewhere in my head was 'L20B' but yeah that's a good deal.

[Rockatansky620]

Win! I'll drop a bid and see how it goes!

[racerx]

That's a good price....

[Rockatansky620]

Ok, got the carb in the mail, and from what I can tell, a simple linkage swap will make this carb useable. EXCEPT, for this missing sensor on the new carb. Here are some oics of the two:

 

 

 

Hers the sensor with a single wire coming off of it:

 

 

Another shot:

 

 

And where it would be on the new beautiful carb:

 

 

Any idea what this sensor is? And how important it is? I'm not thinking very much considering this is a 1973 pickup.

[datsunaholic]

It's not a sensor. It's the idle cutoff solenoid (AKA the anti-dieseling solenoid). The AD solenoid wasn't used until '73.

[anthonydeb]

It's not a sensor. It's the idle cutoff solenoid (AKA the anti-dieseling solenoid). The AD solenoid wasn't used until '73.

 

 

what exactly dose the idle cutoff solenoid do?

[Dguy210]

what exactly dose the idle cutoff solenoid do?

Prevents the car from continuing to run when you turn off the key (e.g. dieseling).

[datzenmike]

All fuel going to the idle circuit has to get past the idle cut solenoid. It's an electrically operated valve that is held open when the ignition is in the ON position allowing fuel to the idle mixture screw. Many motors have a tendency to 'diesel' or 'run on' when the key is turned off. This is caused by many things such as crappy lead free gas (that does not prevent pre ignition as well) and higher engine running temperatures. When the ignition is shut off there is enough heat and compression (and idle mixture) for the cylinder if self ignite. An idle cut solenoid stops the flow of fuel to the idle circuit when the key is turned off and quickly stalls the motor.

[anthonydeb]

ok yes iv noticed that on my carb that wire just gose nowere... im also having trouble with it idleing without using the choke well geting it to run all all the time without the choke