Need help truck dies when I give it gas

[Ed-datsun521]

Well it happened yesterday it's like its running out of gas then I checked the window in the carb and it's struggling to keep it full so I think this is why my truck is staling ?

My truck is a 1971 521 l16

Please any help would be great

 

 

Also before this the carb was getting flooded the floater worked but gas kept going in so I cheked and there was a small peice of rubber hose stuck in between the neddle valve

So I fixed that and now this I need help please

[datzenmike]

If there was something holding the needs valve open it may have been hiding the problem you have now. Possibly the float is set too low and not allowing the needle to open and let gas in.

 

Take the glass off the front of the carb... don't loose the small  round brass sleeve on the end of the hinge pin that's against the inside of the glass. Catch any gas on a rag. Clean and save any gasket or O ring that seals the glass. The float will have drooped down without the gas to hold it up. VERY gently, lift the float with a pencil tip until the needle valve is pushed shut by the float tang. The float should be horizontal at this point. If not, carefully lift out and bend tang with pliers. You may have to lift the needle valve with the pencil tip to get the float back in. Test that the float level...is level when gently lifted to the closed position. Assemble the glass cover... don't forget the tiny brass spacer on the hinge pin. Start and run the motor and check that the fuel is at or near the level line and is not leaking.

[Ed-datsun521]

So I actually fixed this problem on Saturday afternoon but when I was leaving to work on Sunday the truck died on me I would give it gas and it would stall I don't get it do I just need to warn it up really well????

 

 

The problem with the gas getting fed was that it had yet another bigger peice of rubber hose so I actually clogged it now I think I am going to replace the rubber hoses

Any more advise ?when I fixed this test drive it and it ram great like a champ !

 

Maybe it's the air to fuel ?

[datzenmike]

The fuel filter will catch anything behind it but I did take one off once and the filter rattled around inside when I shook it. Piece of crap! Make sure your filter is good.

 

There is also (or should be) a brass screen at the carb banjo fitting where the fuel hose connects. This brass screen should have prevented bits of hose jamming the needle.

[Ed-datsun521]

Oh I guess I am in absence of this small screen maybe I need to find one thanks man for your quick help

[Stoffregen Motorsports]

If you don't have that screen at the banjo, chances are good that yiou already have stuff plugging up your carb. That's why it runs like crap. Now you need to get to the jets and orifices and blow them out with compressed air.

[datzenmike]

I agree. Primary jet or orifice is likely got something in it. Once you try to go above the idle circuit it runs lean and baffs. Clean the needle valve and check that the brass screen is in there first or it will just plug up again.

[banzai510(hainz)]

on 521s i run 2 filters till it clears up. then run the stock one

 

the 521 the fuel hose is in the ite whell and gets dirty and water may run down the hose and rust the tank. most times the idle jets will plug up

[Ed-datsun521]

 

 

This is what is doing still

[Ed-datsun521]

Ok I'm going to get a can of compressed air and try that out and where can I get the screen??

 

FYI the picture above is a video

[datzenmike]

Is the motor warmed up? Because the choke is still on. If it only runs with the choke on then the primary jet is plugged.... or at least something in the primary circuit is plugged.

[Ed-datsun521]

Yeah it was kinda cold but it will run really stupid if I take of the choke and then die

It will also eventually die if I leave on with the choke too

 

What jet is the idle jet ? The one that's rigth under the choke flap?

[Ed-datsun521]

I meant the primary jet where is it ?

[datzenmike]

It's under the front glass cover of the float chamber. The primary is to the left (valve cover) and the secondary to the right. Hard to get at with the carb mounted on the manifold. 

 

There is a 12mm ? cover cap and the brass jet is up inside. I had to grind down the shoulders of a screw driver to get the right size up inside. Have a care as the brass is soft and will strip it you are not firm with it. The brass jet is like a plug with a small hole in it. The hole is easily plugged with sediment... had a mosquito in one once. Might be a good idea to take the float out and rinse the float chamber out as well. Watch out that you keep the primary and secondary jets separate... they can be easily mixed up and will fit! Generally the primary is stamped 100 or just under, and the secondary is around 150- 160. I usually use carb cleaner with a plastic straw to blow out all the tiny holes and passages. 

[Ed-datsun521]

Wow very detailed stuff will have to do this now just got to figure a way of getting that brass filter

Thanks for your help

[datzenmike]

Place an ad in the classifieds. It's very small and lots of Datsun owners have spare carbs and parts.

[banzai510(hainz)]

if dies with choke off then idle jet is plugged.

If choke is on then the main jet is OK as its running off that (2ndary is closed)

 

Possible the main jet is plugged also. put what I would do is put choke on revit up then plug the main side of carb with your hand and open the 2ndary flap and see if it stays running.

 

ck to make sure the carb it tight also

[Ed-datsun521]

Ok so I opened up the glass and took of the floater and sprayed the heck out of all the jets from the intake side I sprayed everything down and I also saw some small parts of rubber come out of the small holes on the bottom of the chamber thanks for all your help my truck drives like a champ now ! Omg ! So happy

 

And just need a brass filter for now I have to drive it like this but I am looking for it thanks again !

[datzenmike]

Its a screen shaped like a tin can with the bottom and top cut off. Fits inside the banjo fitting right where the gas enters the carb. It may be missing.

 

Hello... hello??? Must be having fun driving around. I'll try later.

[Ed-datsun521]

Yeah I'm here I know how it looks I googled it lol just gonna fab one up I think thanks for the help mike

And everyone else !

Yeah it's really fun to drive just changed all the fluids and it's so smooth ! Yay!