Carb leaking

[Ciciro]

If I leave the truck idling it starts to chug and the carb starts to leak pretty badly. 

 

https://photos.app.goo.gl/NYyskmGOC51AQezk2

 

The engine also runs rich, gets really bad mpg, and blows black smoke out the tail.

[Crashtd420]

I can see why your mpg is bad. That's a pretty bad leak.... time for a rebuild or an upgrade......

[datzenmike]

Float stuck or set to wrong height

Needle valve blocked from closing by dirt or debris.

 

There are three screws holding the front cover on the carb. Remove the front. You can clean and reuse the rubber seal. The float chamber is behind it. Place a rag below it to catch the gas and beware... there are small parts that might fall out.

 

Take the fuel line off, unbolt the banjo fitting and unbolt the needle valve assy under it.

 

Clean and inspect. By now you likely have found something wrong or dirty.

 

Take lots of pictures if not sure how it comes apart.

[banzai510(hainz)]

maybe also the accell pump diaphram has a hole also

[datzenmike]

Fuel level would be lower... half way up on the sight glass.

[Ciciro]

I've rebuilt the transmission in this truck twice, but I've never touched the carburetor before. Would rebuilding this be something i should attempt? Any advice?

[racerx]

Depends on your wallet.  I would buy a 32.36 weber but make sure its okay with smog laws in your area.

[Crashtd420]

If you can rebuild a transmission I think you will be alright with rebuilding a carb.... just alot of small parts...

Evaluate it's condition first.... May not even be worth rebuilding...

What type of carb is It?

Make sure you can get a rebuild kit for it with everything you will need....

[datzenmike]

Take it apart. You can do it on the engine. Take the front off. The problem will be obvious and fixable. Needle valve not closing properly so probably dirt or stuck or float... out of adjustment, bent or sunk.

[Charlie69]

If you put the year of the truck in it would help us help you.  85/86 had electronic feedback carbs.  Also check to see that the return line from carb to tank is hooked up and clear.

[Ciciro]

Turns out the float was getting stuck down by one of the jets and couldn't seat the needle. I bent it a little and now it idles without chugging, flooding or black smoke billowing out the back. 

 

Thanks for helping me out

[Crashtd420]

Always nice when you can fix it and don't have to spend money....

[datzenmike]

:thumbup:

[Ciciro]

this truck has had a lot of owners, and it was laden with juryrigs that were trying to counter this problem. Years of crappy idling, poor milage and many frustrated drivers later it turns out it was an hour fix

 

>.<

 

what a world.

[datzenmike]

Usually by the 3rd owner the price to buy it is such that they don't really want to spend much on it. It also coincides with many things naturally wearing out. They just drive it into the ground. That and by the 3rd owner, common knowledge about fixing a 30 year old vehicle has pretty much vanished. For Nissan there were no carbs after '86.5. A mechanic old enough to work on one of these new would be about 50 years old today! There is a whole generation of mechanics today that have never even seen a carburetor. So... good on you for working to keep this truck on the road. Feels good to know more about something than some collage boy mechanic. These old Nissans were made to be fixable not sent away or scrapped. If you can't fix them... you damned well know what wrong with them at least.  

[720Girl]

Resurrect from the grave!