Harley accelerator pump problems

An accelerator pump is a component on a carburetor. It is commonly found on many older vehicles that are equipped with carburetors. The accelerator pump is responsible for providing the momentary additional fuel needed under heavy acceleration conditions. When the pedal is suddenly pressed, the throttle will suddenly open, immediately adding additional air for additional power.

That additional air requires additional fuel, especially in the precise moments after the throttle is opened, this is the fuel the accelerator pump provides. When the throttle is rapidly opened, the accelerator pump will squirt a small amount of fuel into the throat of the carburetor so that the engine can continue running smoothly under increased load.

Usually when the accelerator pump is having issuesit will display a few symptoms that can alert the driver that there may be a problem that should be inspected.

One of the most common symptoms that the accelerator pump is having a problem is rough or sluggish acceleration. The accelerator pump is supposed to provide additional fuel needed during acceleration. If there is any problem with the pump, then there will be a problem in the fuel mixture during acceleration.

Usually, a faulty accelerator pump will result in a momentary lean condition, which can result in rough or sluggish acceleration, and even misfires. Another symptom of a faulty accelerator pump is engine sputtering or stalling.

Rochester Carburetor Troubleshooting

The sputtering is caused by the lack of fuel that is supposed to be provided by the accelerator pump when throttle is rapidly pressed. In more serious cases of accelerator pump failure, rapidly pressing on the gas may cause the engine to stall, again due to the lean condition that can be created when the accelerator pump is not working.

A faulty accelerator pump will typically produce a noticeable effect on the engine performance when it fails or is having a problem. If you suspect that your accelerator pump may be having an issue, have the vehicle diagnosed by a professional technician, such as one from YourMechanic.

If necessary, they will be able to replace your accelerator pump for you and restore proper performance to your vehicle. The most popular service booked by readers of this article is Fuel System Inspection. Our certified mobile mechanics make house calls in over 2, U. Fast, free online quotes for your car repair. Schedule Fuel System Inspection. Service Area. Average rating fromcustomers who received a Fuel System Inspection. Rough acceleration One of the most common symptoms that the accelerator pump is having a problem is rough or sluggish acceleration.

Engine sputtering or stalling Another symptom of a faulty accelerator pump is engine sputtering or stalling. Home Articles. The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details. Related Articles. Related Questions. Car will start and run smoothly but will die when you try to accelerate. Hi there. There may be a misfire on a cylinder that is causing the engine to hesitate on acceleration.

Check all of the spark plugs and wires and see if they have burn marks. If there is burn marks on Traction control off, Stabilitrak, and reduced engine power Hello. The sensor you had replaced previously may still be the cause of your issues. There is likely something in the circuit that is causing the premature failure of the sensor. Test the sensor the same way you did before, Brake pedal too close to gas pedal - BMW d The most practical way to deal with this is to consciously practice moving your foot further to the left when braking.Eldon, Missouri Accelerator pumps.

Often the accelerator pump gets the blame for other problems. It is very easy to test the function of the accelerator pump. Start the engine, and warm to normal operating temperature. Shut off the engine. Remove the air cleaner. The choke butterfly should be fully open, as the engine is warm. Observe the pump jet in the carburetor, and with your hand, work the carburetor throttle to the wide-open position.

You should observe a healthy squirt of fuel from the pump jet. A single barrel carburetor will normally squirt a single stream; while a two or four barrel carburetor will normally squirt 2 streams. If you see the stream s of fuel, the pump is working. It is important to start the engine prior to doing this test. With modern gasoline, it is quite possible the carburetor will be completely dry prior to starting.

If there is no gasoline in the bowl, the pump will not work; and this would give a false result. Bog, Hesitation, Stumble. This paragraph applies to an instantaneous bog, hesitation, or stumble upon acceleration. This paragraph also applies to relatively stock engines with the original carburetor.

We will discuss two types of bog: the first is bog when the vehicle is accelerated from a stop; the second is bog when the vehicle is accelerated from cruise. Most modern carburetors are designed to function with roughly 0. This clearance allows for maximum velocity of idle air past the idle ports. Exceptions to this are GM carburetors with the idle speed air screw, and end carburetors on tripower.Orders placed during the weekends or the following holidays will ship the next business day.

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harley accelerator pump problems

Motorcycle Harley-Davidson Categories All Categories. Carburetors Carburetor - Parts Fuel Systems He gives his suggestions on where to start when you are having fuel delivery issues. Watch how to rebuild your carburetor with our Carburetor Rebuild Class.

Click here to cancel reply. Q: SportsterI am having problems with my carb. I put an RV cam in it, and Ultima programmable ignition system. I would like to know how low I can go on the main jet without starving the motor, and gain fuel mileage. Thank you Any advice will help Bill B. A: You need try to go down on the intermediate slow jet. That is where most of your riding is done. Try dropping one size and see how it goes.

If your spark plugs begin to look white, you are too lean. If you try dropping down more than 1 size, you should also, then, drop your main jet. If the Jets are too far apart in size you will not have a Smooth transition between jets when you really open up your throttle. Your Harley carburetor troubleshooting is not working…there is statement in the video window that the video is currently experiencing problems, check back soon. Can you tell me te best chemical solution for soaking carburetors to clean out gunk without having to disassemble the carb.

Cheers, Pete. Hi, Pete. Sorry to hear this. Can you let us know more about the issue? Have you tried these videos? You will need to take apart the carb. Hi Marvin.

Sounds like you have a torn accelerator pump diaphragm. When you pull the carb, suggest replacing your intake seals if they have not been replaced in a while.

I just cleaned my carburetor on my sportser ,and now the bike will only run when its choked. Hello, I have a Harley Electra Glide with only miles. Bike sat in garage for 1 season without being started. I fired bike up last week started riding after about 4 miles gas started leaking out of carb overflow tube.

I nursed bike home removed bowl on carb noticed some sediment. I cleaned all jets and bowl and installed new float seal, started bike same leak, any ideas? Also any way to properly adjust float height without removing Carberator? Thank You very much! You should do this without a rider or passenger and with the bike in neutral.

They teach you how to check for belt tension and deflection and how to retorque the axle so you can give your bike a smoother ride. As always, Bob stresses the importance of adequately prepping all bolts, consulting your user manual to be sure everything is done correctly, covering any painted areas on the bike and, if possible, working with two sets of hands. Bob LaRosa gives us a great overview on some of the basic tools we need to service our Harley-Davidson from oil-change to custom part install.

Bob shows us that tools are only part of…. It can be a two-man job, so try to complete the service with a friend. Newer bikes mostly use millimeter forks, but most bikes are preset with varying levels of spring in the sliders, so consult your manual before you begin this service. Like any other service, you should clean all of the parts that you remove with parts cleaner to ensure that your bike operates smoothly between services.Rochester carburetors were quite possibly the most widely used carburetor in the twentieth century, with over one million units produced by the Delco Carburetor Company, a division of General Motors.

Rochester carburetors are known for their durability and simplistic design, yet even Rochester carburetors will eventually develop problems. Thankfully, the most challenging part of repairing the carburetor is first identifying the likely causes of the problem.

If the engine will not start due to a carburetor problem when the engine is cold, the cause is most likely a defective accelerator pump. In fact, this is one of the most common problems with Rochester carburetors. The accelerator pump is particularly vulnerable to vacuum leaks, backfires through the carburetor and dirty gasoline. If the accelerator pump is in good condition, the problem may be with a choke that either will not close because it is caught on something, or because the choke linkage requires lubrication.

It the engine does start when cold, but stalls after a few seconds, check whether the idle screw on the driver's side of the carburetor needs adjustment. If the idle screw is not screwed in far enough, the engine simply is not being supplied with enough gasoline to idle. Another cause which can be traced to the carburetor is a float level which is set too low. If the engine will not start when the engine is hot, the choke may be stuck in the closed position, typically due to a lack of lubrication.


However, chances are good that the problem is caused by something other than the carburetor, such as a large vacuum leak, a lack of compression or a fuel supply problem, such as a kinked or clogged fuel supply hose. If the engine does start when hot, but stalls after a few seconds, again, the choke may be stuck in the closed position. If the choke is in the open position, the carburetor's power valve may have blown, or the idle jet within the carburetor may be clogged with dirt.

If the engine either hesitates or stalls upon acceleration due to the carburetor, the carburetor's accelerator pump nozzle may need to be cleaned or the secondary throttle plates may not be closing all of the way. Occasionally, the carburetor's idle jet will become clogged with dirt, which will cause the hesitation or stall. Finally, check to ensure that the vacuum lines which connect to the carburetor are hooked up correctly.

If the engine hesitates or stumbles only upon heavy acceleration, inspect the accelerator pump for the presence of dirt and replace the pump if necessary. The problem might also be caused by sticking metering rods or a defective power valve. The float level may also be too low, which prevents the carburetor from storing an adequate supply of fuel for heavy acceleration.

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.

Hesitation or Stalling During Acceleration If the engine either hesitates or stalls upon acceleration due to the carburetor, the carburetor's accelerator pump nozzle may need to be cleaned or the secondary throttle plates may not be closing all of the way. Hesitation or Stumbling Under Heavy Acceleration If the engine hesitates or stumbles only upon heavy acceleration, inspect the accelerator pump for the presence of dirt and replace the pump if necessary. 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.Discussion in ' Motorcycle Tech Talk ' started by schoonerAug 28, Log in or Sign up.

Bike Talk motorcycle forum. Welcome to Bike Talk, a forum for all bikers and motorcycle enthusiasts. If you are new to Bike Talk, be sure to register for free and join the conversation. There's always someone around willing to help out with questions or give a friendly wave back. All Harley and metric riders are welcome.

Check out the carb and plugs condition. The gap on them is. The book says. CARB 1. Joined: Aug 31, Messages: 4 Likes Received: 0. I don't know what the heck is wrong with it Maybe if you found out what was wrong with yours it could help me with mine.

harley accelerator pump problems

How sure are you on the firing to the plugs? HarleysLRNov 9, Rebuit the carb. New Ignition Coil. New Gas. New Spark Plugs gaped:. New Spark Plugs Wires. New Amp. And the stucker still won't start I don't know what to do anymore. Should I test for spark against the engine block? Hey Cowboy I did the test on the spark plugs and I got spark on both of them. I flooded the carb and fouled-up the plugs. I pulled 'em and cleaned 'em up.

She started but for about 10 seconds then DIED. I remember dancing around with that screw on my carb. This bike has been laid-up for about I'd say 5yrs. But that's for me. I counted-up what I spend to get it running today and hope that's it.

Two new Wide White Wall Tires. One new Ignition Coil.View Full Version : Ironhead bendix carb rebuild, accelerator pump question. That's what a new one looks like. It's made of leather and it'll conform and take on the shape of the chamber just like the old one you just took out. You can lube it with some WD and carefully coax it into the hole. It's not as hard as it looks. Quote: Why did they use leather?

Why did they use cast iron cylinder heads? Why did they only have four gears? Why did they still use a generator? Why was the whole damn bike chiselled out of stone?

Well, neither Harley nor Bendix were invited to help the first Apollo missions to the moon. They were not waht you would call cutting edge of technology outfits. My guess would be that leather had been used in Bendix and other automotive accelerator pumps for about 70 years prior to your bike's manufacture.

It was the only thing way back when that would remain flexible yet free sliding when soaking in gas. Seems amazing today but they just did not have the plastics to stand up to gas and not swell or become stiff. Mind you, if Morton Thiokol had used a leather o-ring in the Space Shuttle that crashed in the late 80s or early 90s or whenever it was, those guys might still be with us today. I had rebuilt a bendix last year, not sure if I had ues the v-twin kit or not, but I had a problem where the float needle in the kit was a tiny bit too big and caused gas to come out the over flow.

harley accelerator pump problems

I ended up using the old part. Something to keep an eye on. Maybe they're for other model carbs? Accelerator pumps are leather because it works.

If you think that's primitive, you should see the universal seals on my Dodge.

harley accelerator pump problems

They're leather, packed with grease and they tie up around the driveshaft like you lace a shoe.

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