Fuel pump problem.

#1
So I installed a fuel pump on my H50. When I have it hooked up it seems to flood the engine where I cannot keep it idling or running. I removed the air filter and fuel is saturated in the air filter and it is spewing gas while it tries to run . If I remove the fuel pump and gravity feed the engine it runs just fine. What could be causing this is it just too much volume?
 
#6
Thanks for the compliment. I just really did not want to go into the side cover. Something I was trying to avoid. Just didn't want any oil issues I will have a catch can but I still I'm trying to avoid it at all costs. However I was just outside and tried it again gravity feeding and it seemed like it was now doing the same thing with the flooding. I'm starting to think it is a carburetor issue possibly.
 
#7
I did have the original carb but it needs to be rebuilt, it just rebuild it and try it. Just gets a little frustrating when you put so much time into a project and it doesn't go your way.
 
#9
The other thing I was thinking about was, either going to a smaller Id for the barb. Or crimping it so not as much air would flow or simply putting a cut off valve on the vacuum line where I can adjust the flow. Tomorror is another day.
 
#10
I would try the sidecover temporarily just to see if it works.
The sidecover has pressure there, not vacuum. If the stock location is the sidecover, the fuel pump might be looking for a pressure pulse and not a vacuum pulse.
It is easy enough to check and rule out, just get a fitting or bushing to just temporarily run it

Or get a walbro style fuel pump that looks for a vacuum pulse.
 
#11
I really do not want to drill and tap the side cover. I was not aware that there is a difference between vacuum and pressure in fuel pumps. You say a walbro fuel pump works off of vacuum? I really would like to stay with a vacuum setup. Due to the fact it being a minibike should it tip or fall with my son I dont want the issue oil being sucked into the pump and carburetor.
 
#12
Do you have to drill and tap the cover? If so, I understand why you wouldn’t want to do that. Especially since the engine is all assembled and painted.

To be honest I never heard of vacuum VS pressure with fuel pumps either. But someone here posted a pic of the factory hoses and if it goes to the sidecover, there is no vacuum there. The crankcase makes pressure, not vacuum. You might need to research h50 fuel pump and see if that is indeed the factory location.

So running pressure to the pump will let you know whether you have the correct type of fuel pump or not. If using the sidecover makes no difference, then you may be able to rule out the fuel pump as the problem and then focus on the carb instead. Diagnosis is usually testing things to rule certain things out of the equation. It could seem dumb but you have to start somewhere imho.

Where is the oil fill plug?
Can you use a bushing in the oil fill port, to install a barbed fitting in that location temporarily just to see if the fuel will flow correctly? If it flows correctly, then fuel pump is wrong and needs vacuum pulse. But if it it makes no difference, then it is time to look elsewhere.
This is how I would approach your problem if I were having this problem. Might not be the best way, but it will work.
I never used the round fuel pumps, so I don’t have firsthand experience with that particular fuel pump
 
#14
That is a great Idea. I just ordered a other pump that is for sure vacuum opperated. The one I have on it now was not specific. But that is a great idea. And no I dont want to pull the side cover off, drill,Tap, replace gasket. Reassemble unless I absolutly have to. If this pump works the next engine I build will opperate pressure so I will already have the pump. LOL
 
#20
Yeah I told my wife that's where I was going to start tomorrow with the pump I have just to find out if that is the case. And again thank you for the compliment. But I'm backtracking and going with powder coating so I got every peace and part ready to go just to backtrack her powder coating instead of paint.
 
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