This Tech Tip is provided courtesy of Howard Halasz – noted GL1500 Expert. Howard is a frequent contributor of technical columns and other information to GWRRA’s Wing World Magazine.
To test the GL1500 accelerator pump, remove the carburetor assembly from the motorcycle as shown in the Honda GL1500 Service Manual. Disassemble the carburetor assembly as shown in the Honda GL1500 Service Manual. Remove the accelerator pump from the RH carburetor float bowl. CAUTION: DO NOT LOSE THE ALIGNMENT DOWELS OR THE O-RING! Remove the float bowl. Temporarily reassemble the accelerator pump to the float bowl. Place the check valve pipe into the accelerator pump as shown above.
Make sure that the float bowl is level, and then fill it with fresh fuel or distilled water. Manually operate the pump lever several times. If the pump is working properly, you will see the fuel or water squirt from the check valve pipe. If nothing squirts from the check valve pipe, it might be clogged. Most of the time, it can be cleared with Honda Spray Carburetor Cleaner and compressed air. If the Honda Spray Carburetor Cleaner and compressed air fail, try boiling the check valve pipe in distilled water. Once the check valve pipe is clear and nothing squirts from the check valve pipe, remove the three screws and disassemble the pump, check the pump diaphragm for deterioration, and replace it if necessary.
Once the accelerator pump is functioning, you can check the pump nozzles. Temporarily assemble the carburetor air horn to the check valve pipe as shown above. (I used an impact screwdriver box in the photo above to support the float bowl in a level position.) Once again, fill the float bowl with fresh fuel or distilled water. Manually operate the pump lever several times. If the pump is working properly, you will see the fuel or water squirt from the accelerator pump nozzles in the carburetor air horn. If nothing squirts from the accelerator pump nozzles, they might be clogged. You can use a .013-inch wire bristle from a wooden handled wire brush as a probe to clear the orifices in the accelerator pump nozzles.
hi, I have an ’88 1500, it seems to flood out after a ride, and sets for about twenty minutes. Then it will crank and crank until you twist open the throttle, then has a strong smell of gas. Any ideas? can one bowl vent tube be stopped up, perhaps? I have a properly working vacuum gas stop valve, also unstopped my gas cap vent which was holding pressure on the tank. I am very reasonably sure the float needles are seating ok, as well Thanks for any help, my e-mail is ruwired89@yahoo.com
Most likely, you have float valves that need attention.
Hi i have an 88 gl1500 and mine runs good but after parked for 20-30 minutes it wont start unless you open the throttle all the way. Im having the exact same problem as steve messaged you august 20th 2017 mine also has a flat spot in the throttle. any ideas?