Carburetor Help

[RatSeven20]

Ok guys, looking for some advice.

 

I've tried to use the search bar, either to no avail or every useful thread I found no longer has any of the images which makes it useless to me.

 

The truck is running, and I can drive down the road... well.. sort of. Here's my issue:

 

When I start the truck I'm getting a ticking/buzzing noise, I can't seem to narrow it down. It's a faster ticking and it seems to sound the loudest from inside the throttle body. I did manage to notice that if I felt with my hand the only part I could 'feel' the noise was what I believe is the dashpot? Its the thing with the screw adjustment in the middle of it in the first picture. I have notice my choke plate doesn't seem to move... ever. 

 

So the truck starts up fine when cold with a quick prime of the pump ( I turn the key just enough that the fuel pump kicks on but not the starter) and a quick 3-4 pumps of the accelerator pedal and voila!  She runs good , albeit a little high on the idle, until she starts to warm up. 

 

If I take my hand and open the throttle it seems to rev up fine with minimal sputtering etc. no issues, no dying.. fairly smooth. If I take off down the road I usually get to 3rd gear and then she starts falling on her face. After that it never seems to straighten out. It will spit and sputter, cut in and out, and then usually die altogether. When this happens it becomes much more difficult to start.

 

So basically the truck runs like crap under load.

 

I did notice a previous owner has already capped off a few vacuum lines.

 

Here is what I have done /replaced:

 

New Fuel Tank

New Carson fuel pump

New K&N fuel filter

New fuel lines

New distributor cap, rotor

New plug wires

New plugs leading and trailing (intake / exhaust)

 

I have verified that the fuel pump is still running when the truck is having its issues. I have also taped off part of the carburetor to see if it helped, which it does run a bit smoother, but still cuts in and out and has issues.

 

I'm not sure whether to rebuild this carb (if it is the carb) or buy a weber and never look back. I don't really want to spend any more money on the truck than I have to, as the point is for it to be a cheap , reliable work vehicle with some retro coolness.

 

Any help is appreciated.

 

[Doctor510]

Probably really dirty inside the carb.  

[datzenmike]

Try Google for your search and add Ratsun at the end of the question.

 

 

 

This needs to be plugged. and the one with the screw in it is the vacuum advance and goes to the distributor. Geezus, previous owner was a tool.

 

 

 

Crushed line can't be right. May just be the bowl vent.

 

 

 

This is an ECC carb with an electric solenoid that constantly adjusts the primary jet to set the air fuel ratio. That buzzing is probably it. You have an O₂ sensor and a 6 wore electrical plug at the back of the carb???

 

When cold, and you step on the gas, the choke should snap closed. If not, lubricate the linkages around and under the round choke heater at the rear with carb spray or WD-40. Hold the throttle half open and work the choke closed and open to clear them. The wire to the choke heater should have 12 on it but ONLY when running.

[RatSeven20]

Thanks for the replies. I'm looking at the advance line that was capped off, but can't seem to figure out where exactly it is supposed to be plugged in at the distributor? I was going to run to the parts store and get some more line to re-attach it. And yes, I have the o2 sensor and what appears to be the ECC carb.  Considered getting a weber, but my original idea down the road was outfitting a set of Keihin FCR36 and a custom runner. I'm a motorcycle technician by trade just haven't dealt with car carburetors very much, they operate on the same basic principle but everything is sideways to me! lol. As for now though I just want to get her running smoothly.

[datzenmike]

Under the front of the intake are 3 steel lines going over to the other side of the engine (unless removed) One of them can be used to sent the vacuum signal to the distributor.
 
You still need to cap that open metal line center right in picture near the hose clamp....

 

..and I'm pretty sure that's the vacuum advance with the screw in the ends.
 

[RatSeven20]

ok so traced some lines and found where i believe it was unhooked, which was basically right beside of it, the other screwed off hose in this picture. got some hose and reconnected that line. I don't have a helper so if i move the throttle linkage while cold , by hand, the choke plate should still operate no?  I can easily move the plate with my finger. as for the open tube, I still have the line to that running to the air filter box, it's just unplugged while working on this. Ive got a little rubber cap I place on it while tinkering. I feel lost not having a manual at my fingertips, everything is either google, Mike, or tracing it by hand and trying to figure out exactly what it is and where it goes/comes from. It's fun! but also frustrating.

 

[RatSeven20]

Went for a short drive. 4-5 Miles. Truck ran much better with the advance hooked back up. Ran pretty good except for full throttle. 1st and 2nd fairly smooth, full gas in 3rd gear and she fell on her face and wouldn't do anything until I let her die and restarted. Then drove normal (minus minimal sputters) back to the house not going more than ¾-ish throttle.

 

I went ahead and pulled the plug off cylinder 1 to look at fueling, and she does seem to be running lean although a small bit. Looking at the ground strap I'd say the ignition is advanced a little far and it could possibly use a shorter plug gap. Going to give the distributor a slight twist to retard the ignition, drop the idle down and check again after a trip to work. 

 

[datzenmike]

Whoa... that's extremely lean.

[Charlie69]

Is that an intake or exhast plug?  On the bottom of the sideof the hood should be a vacuum diagram. 

[racerx]

Too light and white, looks lean. How many turns of idle mixture? Should be tannish or a little black in color. If not sure of color go on line tons of pictures of what plugs should be.

[RatSeven20]

yeah the white strap is usually an indication of too much timing / too much plug gap which is overheating the spark plug. definitely needs to be richer which makes me think its falling on its face due to running out of fuel up top. main jetting is read off the base of the plug and the ceramic. Only thing left to do is clean the carb I suppose.

 

I have no clue where the air mixture screw is on this thing. lol

[datzenmike]

Plug over heating is caused by lack of cooling fuel in the air coming into the combustion chamber. Much of the combustion chamber heat is absorbed by fuel evaporation cooling.

 

What NGK plug did you use? Should be BPR6ES intake and colder BPR5ES exhaust

[RatSeven20]

Plug over heating is caused by lack of cooling fuel in the air coming into the combustion chamber. Much of the combustion chamber heat is absorbed by fuel evaporation cooling.

 

What NGK plug did you use? Should be BPR6ES intake and colder BPR5ES exhaust

Yes. Absolutely. but you can also read a plug for where the fueling issue is - i.e. timing, fueling, ignition, etc.

BPR6ES intake and BPR5ES exhaust.

 

I ended up figuring it out. The guy who messed with this before me was an idiot. He not only had the sight glass upside down, he set the float height to that...  I disassembled the carb, cleaned it, polished the jets, and reassembled. Re ran vacuum lines, replaced some, adjusted the distributor and adjusted the idle and fuel mixture. Truck starts runs and drives great now.

 

Now just to take care of that nasty exhaust... had a shop quote me $250 today to run a straight pipe to a turn down before the axle ... I laughed on my way out the door. 

Looking for some other shops tomorrow. Then we will be in business!!

[RatSeven20]

Once I got my head around everything being sideways in the carb everything gelled lol. 

[datzenmike]

Muffler pipe is cheap. They're crooks and you were right to laugh in his face. Always run some form of muffler

[Tinman]

Once I got my head around everything being sideways in the carb everything gelled lol. 

 

It's good you are fixing the original feedback carb.  The Webers are fine, but the feedback carb when working right is actually very good to drive and gets much better mileage.

The system turns off the fuel when coasting.

 

I get about 31mpg out of my 2wd standard cab with the original carb in California.  17mpg with the diagnostic plug open to bypass the "control".

 

I'm stuck here, as far as smog goes, but I have rebuilt the carb twice in 32 years and the truck just hums along on the freeway. 

 

You guys NOT in Cali are pretty lucky, but here they will fail you for the wrong color paint!

[banzai510(hainz)]

Get a quiet muffler.

If I had to do it again I would go "quiet" on trucks

 

 

I got a Dynomax SUPERTURBO . Its great when your 16-29yrs old   Now I like sneeking back in my neihboorhood to catch whats going on!!!!!!!!!!

[datzenmike]

C'mon Hainz your wife's boy friend could hear you 5 blocks away and had time to get dressed and jump out the bedroom window

[banzai510(hainz)]

I knew that one was comming MIKE!!!!!!!!!! As the Harley Bikers guys say ,Loud Pipes Saves Lives!!! Especially your own

[weldingrod]

Nissan wants about 1500 for a rebuilt carb, Baker's (with my discount) around 700. Anybody getting them anywhere else at non-stratospheric prices?

 

Hate to pay more for a carburettor than the truck cost me.

[datzenmike]

New Weber is $300 US. Comes with adapter bolts gaskets air filter... Pierce manifolds sell the genuine ones (made in Spain or Italy not the Chinese POS knock offs)

[i need help & guidance]

where is the vacuum line that goes in to the fast idle kick down hammer thing dash pot ? i dont see it in pix

 i dont see vacuum line  going in to the side of dashpot. (thing with flat screw driver adjustment in middle of it) .  and dont throw any of the old hose pieces.

 the hose pieces with white or silver or gold color on them are 1 way vale or air restricting metering hose. ...like the one you have the Philips screw stuck in it, 

my hose there has gold  color  and has a air restricting metering device inside of it. . so you wont be able to just hold it up and look through it , but it is not clogged 

... so i had to go to oreilley and buy that little clear plastic box of countless little white barbed vacuum line hose couplings , then carefully barley just trim  back the old gold colored hose's jagged ends with a razor and put the barbed coupling in and add a little piece of new hose to it .

...on my carb that dashpot thing has a hammer like pusher thing that comes out of bottom  , that when vacuum is applied , pushes outward and kicks the fast idle cam out of way , when dashpot adjusted correctly between hammer and set screw it contacts , there is very little light or gap between them.

on mine  dashpot gets it's  vacuum line , off a nipple on driver side of  a device with electrical wires and additional vacuum lines going into  it, up on fire wall , mounted on driver side above brake booster

 the other vacuum lines going to this electrical device had a black T on mine  up along fire wall , that was broke ,

so i had to replace with new T also and reconnect those vacuum hoses

before  new vacuum line down to dashpot would work

Edited February 1, 2019 by i need help & guidance

[datzenmike]

People don't realize that with a few small tools and a couple of hours they can 'rebuild' a carb. 95% of it's just cleaning it and 5% replacing the accelerator pump and making some adjustments. A good kit is about $30. A few small wenches and screwdrivers, cleared table space, a camera, some carburetor spray in a can with a straw and time.