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Post by mbart13 on Apr 11, 2019 17:22:22 GMT -5
My 1987 Honda Elite Iowa sat for quite some time. When trying to start it using starter fluid it runs at very high rpms for about 5 seconds then dies—even if I rev it to full throttle. It doesn’t seem to be getting any gas. The list of what I have done:
Put in new gas Cleaned carburetor Installed new vacuum fuel pump Sucked on vacuum line to prime fuel pump New spark plug Air filter is fine
What am I missing?
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Post by FrankenMech on Apr 11, 2019 21:44:53 GMT -5
Are you using a vacuum fuel PUMP or a vacuum operated PETCOCK? Is your fuel tank above or below the carb?
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Post by micscience on Apr 11, 2019 22:54:48 GMT -5
I would inspect all systems through the fuel train such as fuel lines for blockage, fuel filter you can usually tell if you are getting fuel to the carb you can smell it. Remove fuel line from carb and crank the engine see if fuel squirts out into a container adequately. Also check for vacuum loss throughout your vacuums hoses look for cracks or holes. I'm not familiar with the Honda elite but they are all the same it's just the delivery system that is different.
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Post by mbart13 on Apr 12, 2019 7:36:02 GMT -5
Are you using a vacuum fuel PUMP or a vacuum operated PETCOCK? Is your fuel tank above or below the carb?
The gas tank is above the carburetor and it is a vacuum fuel pump.
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Post by mbart13 on Apr 12, 2019 7:41:08 GMT -5
I would inspect all systems through the fuel train such as fuel lines for blockage, fuel filter you can usually tell if you are getting fuel to the carb you can smell it. Remove fuel line from carb and crank the engine see if fuel squirts out into a container adequately. Also check for vacuum loss throughout your vacuums hoses look for cracks or holes. I'm not familiar with the Honda elite but they are all the same it's just the delivery system that is different. I checked all lines for blockage. How do I check for vacuum loss? The only time I was able to get gas to the carburetor was when I had my hand over the air filter connection hole with the air filter off.
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Post by GrumpyUnk on Apr 12, 2019 10:12:18 GMT -5
Most systems that plumb the tank above the carburetor inlet use gravity feed to supply fuel to the float bowl.
Many scooters are supplied with a vacuum-operated fuel petcock that interrupts fuel supply to the float bowl until vacuum pulls a diaphragm to open the internal valve and allow fuel flow. Most petcocks like that will have a vacuum line that leads to the intake port. You may apply vacuum to that line manually or using a 'mighty vac' or other vacuum pump. When you do, fuel should flow from the tank, through the valve, and out to the fuel line connected to the carburetor inlet. If the float bowl is below its full level, the valve will allow fuel in until the float closes the valve and flow is stopped. The vacuum petcocks come in two styles, one attached directly to the bottom of the tank, and one plumbed from the tank outlet to the valve inlet, and from the petcock outlet to the carburetor inlet. Either style will have a line plumbed to the intake manifold. When I start an engine after replacing the carburetor, to save on starter wear and keep power draw from the battery to minimum, I disconnect the vacuum line to the intake, and either suck on the line, or use a MightyVac hand pump to apply vacuum for 10-15 seconds. That allows enough time for fuel to flow and fill the float bowl prior to attempting to start the engine. If you question fuel availability in the float bowl, check to see if your carburetor has an accelerator pump. Many have a 'leaf' of metal that is moved when the throttle is opened. The metal 'leaf' will push down on a vertical rod on the rear corner of the carburetor, causing a tiny jet of liquid fuel to be squirted into the carb air inlet opening just 'outside' the throttle plate. With the air cleaner ducting removed, you can see the squirt of fuel each time the throttle is opened if you have an accelerator pump feature. If it squirts, you know you have fuel in the float bowl(or did). Some work the throttle 3-4 times to squirt liquid fuel into the inlet prior to starting a cold engine. It (the squirt) provides a richer mixture to ease in starting the engine. If your accelerator pump fails, you will likely experience 'bogging' when you open the throttle. tom tom
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Post by FrankenMech on Apr 13, 2019 0:41:19 GMT -5
Are you using a vacuum fuel PUMP or a vacuum operated PETCOCK? Is your fuel tank above or below the carb?
The gas tank is above the carburetor and it is a vacuum fuel pump. Seems like you have identified your problem.
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Post by micscience on May 10, 2019 18:00:45 GMT -5
mbart13 try starting the engine and spray either carb cleaner or water in the general area of your air intake and your vacuum hoses. If you notice a change in the way the engine runs you may have a vacuum leak.
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Post by GrumpyUnk on May 11, 2019 10:57:42 GMT -5
You can use a propane torch fitted with a length of rubber tubing to direct more HCx around the intake, engine running. If it improves in specific areas, you likely have a leak, and the propane adds enough fuel to make it burn better. I would like to see a picture of the petcock and the fuel pump, or at least the fuel and vacuum hose routing if one is available. tom
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