A couple carb questions...

[Buzzbomb]

I'm having a few issues with my 1980 L20B Hitachi carb that I'm going to try to fix with a rubber mallet and/or some carb cleaner before taking it apart. It seems to be flooding the float bowl to the top of the window, and I was getting gas dripping into the secondary. I'm thinking this is either to junk in the needle/seat or a sunk float. I don't really see why this would be the fuel pump, as it was all running fine before my head gasket replacment.

 

Long story short...If I need to get a kit or at least a needle/seat + float, where do I find the carb number? I know this probably seems like a dumb question, but I looked everywhere on that carb and couldn't seem to find the number. There were numbers on the choke, but I'm not sure if those were teh numbers? Any kits better than others?

 

If the quick and dirty fixes don't work, I'll need the number to get the right kit. If by some far flung chance the quick fix DOES work, at least I'll know where to find the number for future reference.

 

A Weber isn't an option at this point. I have to pass an emissions test AND a visual test, plus it's too expensive right now.

 

Thanks!

[datsunaholic]

Sometimes the fuel return line plugs up. When you did the head replacement, you DID hook the return line back up, right? Otherwise the fuel pump overpowers the needle valve.

 

Assuming you did hook it up, sometimes blowing it out with compressed air does the trick.

 

If that's not it, the float might be stuck. Or sunk, as you mentioned.

[Buzzbomb]

Sometimes the fuel return line plugs up. When you did the head replacement, you DID hook the return line back up, right? Otherwise the fuel pump overpowers the needle valve.

 

Assuming you did hook it up, sometimes blowing it out with compressed air does the trick.

 

If that's not it, the float might be stuck. Or sunk, as you mentioned.

 

I'm thinking what might have happened was when I was turning the crank to check the valvetrain alignment marks, fuel was being pumped into the bowl to the point where it finally just blew the needle of the seat. Either that or some crud lodged itself in the seat when I was doing that and was blown out and finally dissolved.. I hope it stays running like it is, knock on wood :w00t: . It is now running really good :)

 

I have to say it again...THANKS so much for those that helped in my posts. I am super grateful, and like I said in one of my earlier posts, I'm going to have to order me a Ratsun sticker for my rear window :cool:

 

I'm still wondering where to find the carb number for future reference?

Edited March 20, 2009 by Buzzbomb

[datsunaholic]

Well, the carb SHOULD be a DCH-340 (which is less than helpful being that the DCH-340 was used since the early 70s and had dozens of variants (including being used on the Isuzu Chevy LUV).

 

National lists their carb kit as the DAT-704 for that particular variant (as long as it's the right carb for a 1980 720). The '79 kit is different.

[Buzzbomb]

Well, the carb SHOULD be a DCH-340 (which is less than helpful being that the DCH-340 was used since the early 70s and had dozens of variants (including being used on the Isuzu Chevy LUV).

 

National lists their carb kit as the DAT-704 for that particular variant (as long as it's the right carb for a 1980 720). The '79 kit is different.

 

Yes, it's a DCH-340. The problem I have is...WHICH ONE (other than the original Datsun carb for 1980 720) ?! :lol: . It's funny the Haynes manual tells you to look up the carb number, but not where to look it up. The only numbers I saw were on the choke cover, but maybe I wasn't looking hard enough. I'm glad to at least have a carb kit number, though, so thanks for that.

 

Like you said, there are DOZENS of variants for many different apps. My truck is running really nice now, but I'd still like to have the info for it just in case.

[sean1978]

On a L16 with no return line what happens to the fuel when the needle plugs the fuel hole in the carb? does the fuel circulate back and fourth in the pump?

 

I'm having an issue with my carb flooding over and over after a head gasket replacement also. I actually switched carbs last night to a second freshly rebuilt unit and it seems to have the same problem. It's like the fuel is powering past the needle. I have cleaned my lines and replaced my fuel filter.

[Braden]

sounds to me like either your float is inproperly adjusted, sunk, or the float needle is stuck open, you do not have to disassemble the carb to replace/adjust the float, simply remove the float window, as far as a carb kit i have used the walker kits with much success walker part number is 156168, available for 20 bucks at any oreilly auto parts (probably not in stock but can get it in 3 days or less) the hitachi carbs are fairly simple to work on and the carb kit comes with a worksheet

 

i would recommend getting a gallon of carb dip made by berryman chemtool. its good shit and can be used over and over for carbs or any parts you have, it actually eats away the varnish in the passages instead of the carb spray the simply thins out dirt grease and sludge here is my carb after i used the kit and the dip

on another note the carb kit comes with a new needle valve and instructions to adjust the float correctly, the kit is uviversal with extra gaskets for other models of hitachi carbs so you wont use all of the parts

Edited December 3, 2009 by ghettobraden

[sean1978]

Already put 2 freshly rebuilt carbs on the car. Car ran before head gasket failure with the first one.

[ggzilla]

The Carb Number is printed on the alumuminum surface of the carb, near the sight glass. Usually it is worn off and cannot be read. Never fear, the number is not important to the rebuild kit.

[Braden]

Already put 2 freshly rebuilt carbs on the car. Car ran before head gasket failure with the first one.

 

it may be good to double check the float settings to be sure they are correct, then you can move on to other options that might be causing your problem, hey your in charlotte? do you know where Whatever It Takes Tranny Shop Is?