1985 nissan 720 carburetor adjustment

It is important to follow all linkage and lever installation instructions. The number one and two reasons for tuning errors are improper linkage installations and over tightened linkage nut, causing a binding in linkage assembly.

Do not depend on the factory delivered settings. Check them before the carb is installed. All settings are done with choke disengaged or warmed up so that the choke is fully opened and disengaged. This is done on automatic choke carburetors by first opening the choke butterfly by hand and inserting a wood block or wedge of some kind to hold open while the linkage is cycled linkage operated through its full movement to clear the choke cam.

You will hear a metallic click as the cam is released. You can check the fast Idle screw under the choke assembly to confirm that it is not in contact with the choke fast idle cam.

Set the Idle stop screw speed screw see fig 1 by backing out the Idle speed screw until it is not in contact with the throttle stop lever. Cycle the linkage again to be sure that the linkage comes to close without any assistance. Set the mixture screw see Fig 1 by first screwing in until the screw stops, bottoms out.

Carburetor adjustments on a nissan 720 pickup?

Back out the screw 2 full turns. Start the engine, the engine will run very slowly more like a tractor. As long as the engine stays running idle speed is not important at this point.

The first thing to do is not set up the idle speed, but to set the idle mixture screw to lean best idle setting. The engine should pick up speed and begin to smooth out. Use your ear, not a scope or tuning instruments at this point. You want to tune the engine by sound.

Adjust to best, fastest and smoothest running point. Now that the mixture screw is at its best running location, you can adjust the idle speed the screw. Check and set idle to your driving preference. Put the car in gear and apply slight load, AC on and set the Idle as you like it. Recheck timing and vacuum hook ups.

Recheck mixture screw to lean best idle again. If all is still best and smoothest idle then confirm and note the final settings. To confirm settings with the engine running. Start by screwing in the mixture screw and count the number of turns it takes to bottom out and note if the engine dies. Also check the speed screw and note how many total turns from initial contact.

You may have opened turned in the speed screw. Your final setting should be under 2 full turns. Reset the screws back in to the best final settings Per your notes and go on a test drive and have fun. If the settings are other than described then you may want to recalibrate the idle circuit low speed circuit to your engines needs. Simple Rules for low speed calibration If the mixture screw is more than 2 turns out then the idle jet is too lean too small.

If the speed screw has to be opened 2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition.

1985 Nissan Pickup Specs

See pictures and notes in the tech 2 article supplied in the kit instructions, view and please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size. EXAMPLE With the speed screw set at no more than two 2 turns in after contact with the stop lever; and the best idle occurring with the mixture screw set at 3 turns from bottom, indicates the need for a larger Idle jet.

Achieving the best idle at under 2 turns indicates the need for a smaller idle jet.By BondobucketNovember 17, in Engine. First of all I would like introduce myself my name is Josh. I am an avid minitrucker and own a few minitrucks. This forum has been very helpful with some minor issues that I have had with my Nissan The problem that I have encountered now, I am having a hard time trying to search for a specific answer. My Nissan has been garaged for a number of years from the previous owner.

It has 53, orig. Nothing has been tampered with or messed with. The truck is entirely stock. Upon start up the engine will rev until I press the gas pedal to kick down the carb.

As soon as I do that the idle drops in rpms and stalls. I have driven it by feathering the gas while working the brake and clutch to raise the rpms. It drives perfect at highway speeds 65mph. As soon as the truck is put in neutral the rpms slow to the point that the truck stalls.

I restart the truck with no problem after the stall. It just does not seem to have a smooth idle. I have not touched the idle mixture screw because this problem has just came about and I figured that if I were to make an "adjustment" that I would be constantly trying to get the fuel mixture correct.

Could the problem be the EGR, or the anti dieseling sensor, or the throttle valve switch, or any other part that could cause this with my stock Hitachi carb. I'm at a loss for solutions for this problem. My Haynes manual does not answer these questions.

Any help would be greatly appreciated. Later Josh. Thats why you got to pump the gas. When you choke is ON you got enough vaccum to pull gas from the main jet or 2nd barrel side. Thanks for the response. Yes the carb is stock. I will check everything that you listed tomorrow morning. I'll respond with my findings. First, have someone turn the ignition switch on, off, on, off, on, off without starting.Please see the announcement in the Forums.

No new members are being accepted at this time. Thanks for all the support over the years, and happy trails. I recently found out that I have too much gas in the sight window on my hitachi carburetor. I also have wet and dirty spark plugs on the exhaust side. The truck bogs down and hesitates when I give it gas sometimes.

Not all the time. Earlier in another thread I had said that the sight level was ok but I was wrong. I finally moved some things out of the way and when I shook the truck I finally could see the level of the gas way up over the top of the sight window. It''s suppose to be level with the dot in the middle of the round sight glass window.

So I have way too much gas in the bowl. Danzimile said that the sea foam can make stuff come free and clog up the carb.

1985 nissan 720 carburetor adjustment

I'm now thinking that the needle value that the float attachs to is old and worn out or clogges with gunk and is not closing right and letting too much gas into the carburetor bowl? Does that sound right?

1985 Nissan Pickup Specs

If that is the real root of my problem then how easy will that be for a good Nissan Mechanic to fix? What would you think it will cost to have the carburetor fixed?

Share Facebook. Views: Would this also make the truck hard to start in cold weather? It seems that most of my problems happen when it's really cold outside. The truck ran fine yesterday when I drove it about 12 miles to the store and back.

The trouble it that it also drove good when it was really cold outside and I drove it for about 40 or 50 miles last Sunday and Monday. Then last week it bogged down again on me for the second time.

I'm going to let the truck cool down to ambient temperature and the pull and clean all the exhaust spark plugs as they are really carbon fouled up.InNissan released one of the last members of its fifth generation of pickup trucks, the Nissan This particular vehicle came in two trims and was one of the more popular pickup trucks during its release.

The generation was first released inwhen it succeeded the pickup. It was replaced by the Hardbody pickup in Truck beds were available as regular or base types and extended- or long-bed types. The base engine for the Nissan pickup was a 2. It used a computer-controlled carburetor as its main fuel system, but a fuel injection system was also introduced late in with the modified Z24i engine. Standard transmission was a five-speed manual, with an option for a three-speed automatic.

It also came standard with front disc brakes and rear drum brakes. The Nissan models were released with redesigned hoods and smoother sided beds with removable tailgates.

Bed designs of the earlier models had problems with welded seams that were exposed and prone to corrosion. The truck's dash pod featured new round-shaped meters and gauges.

Most models had dash pods with no tachometers and clocks, but some were released with standard voltage and oil pressure gauges. This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.

To submit your questions or ideas, or to simply learn more about It Still Works, contact us. References Nissan Pickup Off-Road. About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.Select your vehicle options to narrow down results. View by Lookup Code. Band-Hose Select vehicle options to narrow down result.

Band-Hose Add To Cart. Bracket-Fuel Hose N Replaced By: NA.

Datsun 720 - Carb Rebuild (Episode 6)

Clamp-Hose Require Quantity: Clamp-Hose Select vehicle options to narrow down result. Fitting Vehicle Options: Z Clamp-Hose To Hose Select vehicle options to narrow down result. Clamp-Hose To Hose Clamp-Hose To Hose W Fitting Vehicle Options: 2WD. Clamp-Hose To Hose E Connector-Fuel Feed Piping W Connector-Fuel Strainer Cover-Upper W Detector-Fuel Select vehicle options to narrow down result.

Detector-Fuel W Detector-Fuel R Element Assy-Paper W Hose Assy-Fuel Select vehicle options to narrow down result. Hose Assy-Fuel Hose Assy-Fuel W Hose Assy-Fuel A Fitting Vehicle Options: 4WD.To the point where I cant drive it untill I figure out whats going on.

1985 nissan 720 carburetor adjustment

I checked all the linkage and wires acclerator wires idle screws, the float. Nothing seems stuck or broken. Could it be something internall? What about a vacum hose that cracked or fell off? Maybe the carb that has miles on it is bad? The only thing I can suggest is what you already checked. Throttle linkage and associated parts and adjustments.

Make sure something didn't get between the linkage and the idle speed screw adjustment. Check the linkage cable itself - it may be binding not allowing the engine to return to idle.

Check the throttle return spring. It may have broken, slipped or faild in some way. It's not likely an internal problem, but check to see if the throttle plate s are completely closed with the engine off, choke open. Look down the carb throat. If the plates aren't fully closed, you still have a linkage problem somewhere. A vacuum hose that is cracked or fell off ususally won't cause high idle speeds - just lousy, rough idle.

Could it Might be wrong but does it have an auto choke? Trending News. Hailey Bieber endorses Biden — while dad backs Trump. Ex-Obama adviser: Covid infections 'going to go up'. Trump turns power of state against his political rivals.An engine idling too high can be annoying.

It makes your car or truck feel like things just aren't right, and it can draw unwanted attention at stop lights and in grocery store parking lots.

Luckily, there aren't too many things that can cause what's commonly referred to as a fast idle problem. Some of the causes are super cheap to repair; others are serious bank breakers.

You can usually figure out what's causing a high idle problem and estimate the cost before you open your wallet. The small engine in this truck is similar to many other engines in Nissans and other makes.

Most of them operate in a similar manner and regulate the engine's idle speed using the same systems, so this information is useful for many car owners. I have a Nissan Hardbody with a 2. It idles at 1, rpm, which doesn't go down after it's warm.

1985 nissan 720 carburetor adjustment

I checked all the plugs and everything seems to be plugged correctly. Any help would be appreciated. The first thing to do is to check for vacuum leaks. Then make sure the throttle linkage is free and moving smoothly. Also check the fast idle cam. Make sure it isn't frozen and is adjusted properly. Here is the adjustment procedure:. When faulty engine idle is the symptom, there can be any number of possible causes.

Always check the inexpensive, common problems first. More often than not, an idling problem is due to a cheap part failing or something that has fallen out of spec or adjustment. Older cars will try to compensate for worn spark plugs or a failing ignition coil by increasing the engine idle.

An engine with a problem that is idling at revolutions per minute is far more likely to stay running than the same engine trying to idle at RPM. If the clearance is out of spec, adjust it using the adjusting screw to 2. Matthew Wright. Matthew Wright has been a freelance writer and editor for over 10 years and an automotive repair professional for three decades specializing in European vintage vehicles.

Updated November 04,


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