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Honda BF20D Fuel Pump

L

LKFitzgerald

New member
Without going to far into it, I believe my fuel pump is going out. I haven't taken off the engine yet, but when I do was going to disassemble and inspect. I was also thinking about hooking my Dual Vacuum/Pressure Hand Pump to it. I have a shop manual, but couldn't find any specs on the PSI I should be seeing. Has anyone done this test before and could throw some knowledge my way? Thanks for any input and your time guys!
 
Some things to check and do FIRST when you think you have poor fuel delivery;

Make sure the primer bulb arrow points UP. If it points down, the check valve can leak fuel back to the tank.

Check the quick disconnect for the hose. Vibration can wear the pin and check valve ends so that the valve doesn't open all the way. Also, if the latch isn't properly locked, the same thing happens ie: the valve won't open properly and fuel flow will be restricted.

Empty the fuel chamber periodically. That's the black, rubber, round thing attached to the engine oil dipstick tube. The fuel chamber tends to act as a water trap. That's not what it is there for but it does. If water accumulates in the chamber it can starve the carburetor for gas.

Finally, to answer your question, the fuel pressure specification is:

19.3 kPa (2.8 psi) @ idle (900 rpm)

Or, as I like to tell folks that don't have a low pressure gauge laying around....
...a good,solid GURBURBBLE of gas when you spin the engine over.

Good luck.
 
Thank you for your recommendations and answer. My thought process is the same, and have literally replaced the whole fuel system and fuel pump being the last part. Problem was before getting this engine it sat for 3.5 years and we all know how that goes...

My issue has been upon priming and initial run she would pur like a kitten, then would start to sputter and bog. I would go from 6k to 4k RPMS and would get stuck there. I would also gradually begin to hear what I THINK was the ticking of the fuel pump getting louder and louder like it was starving for fuel.

I took fuel pump off last night and put negative pressure on the inlet and positive pressure on the outlet; sealing off opposing barb each time. Neither the inlet or outlet could hold a vacuum or pressure. This leads me to believe my one way valves are shot.

Ordered a new pump and just for the heck of it opened it up to inspect. Diaphragm and one way valve both have rough, "dried out" edges and this design definitely doesn't look serviceable. Or is it?

Pump should be here next week and can report back with results.
 
I have never opened one of these pumps nor have I ever had the need to replace one. They are very reliable in my opinion.

I do know that no service parts for them are available through Honda so I am sure that replacing the whole assembly is the correct repair for a faulty one.

Looking forward to your success and report.

Good luck.
 
So replaced fuel pump and still have same issues. Can run wide open for about 3-4min then start hearing a knock. I pulled her back and whenever throttle is applied again it gets to 4k rpm and never passed that. At idle I can here a slight ticking, so maybe I have an exhaust valve slightly stuck open?
 
Yes, not a bad idea to check valve adjustment. But I would also look at timing and how loose the belt might be. I would do the timing/belt slop check first because I think that's easier.

Good luck.
 
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