See full version: Carburetor Troubleshooting
As carburetors age, the material around the throttle shaft located in the base of the carburetor wears out from constant movement. It causes an increase in the tolerance between the base and the t-shaft. This increase allows air to leak, making the engine run rough at idle speed. It also makes the necessary adjustments very difficult or impossible to perform. more
There is a vacuum-sensing mechanism within the power valve of the carburetor, which opens to increase fuel intake when vacuum drops. If this mechanism fails or the power valve is clogged, you will have to replace it. You can usually get a new power valve with a carburetor rebuild kit. [links]
I have spent over 20 years rebuilding carburetors for many different types of applications. You don’t always need to replace one and that’s why I put together this guide to help you identify the symptoms of a carburetor having problems, and learn some possible ways you can work on damage control.
You can find the spring housed in a black plastic choke by the side or down on your intake manifold. The black plastic cover contains an electric heating mechanism to heat the spring. Alternatively, heat from the engine turns the spring choke on your intake manifold. here
These tables offer a quick look-up if you know your year and engine size/model. Click on " View " and be taken to our picture identification page for the remanufactured marine carburetor you selected. On this ID page you will be able to visually verify that you have selected the correct carburetor for your application and then place your order or call 800-250-8746.
Our staff will verify you have ordered the correct remanufactured marine carburetor from the carburetor number and boat information you fill out in the ordering process. All remanufactured marine carburetors have a complete one year warranty. They are calibrated and idle adjusted for your vessel .
Alpha/Bravo/ Crusader
Including all makes and models for
single and twin engine I/Os and inboards [links]
The float in the carburetor regulates the amount of fuel or gasoline which resides in the reservoir. The reservoir of the carburetor is where the fuel is sucked into the intake manifold. A bad or sticking carburetor float causes engine problems. Watch for certain signs and symptoms if you suspect the carburetor float is sticking.
One of the signs that the carburetor float is sticking is when the engine will not idle. The float is not letting enough fuel into the reservoir, allowing for a constant idle of the engine. The carburetor float is stuck in the closed position, and only a small amount of fuel is seeping into the reservoir.
The engine will begin to stall or hesitate when the carburetor float sticks. This symptom develops under driving conditions when the operator attempts to accelerate. The engine will act as though is it going to die, but catches and begins to accelerate normally. The hesitation of the engine is a similar event. [links]
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. here
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 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.
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 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.