Need fuel pump advice

[David wulf]

Installed fuel pump on my super bronc with a hm100 . I used the block pulse fitting that the stock one ran off of . The pump works just fine but it seeps oil out of the back of the pump . Is this normal ? could I use the breather tube that comes out the little valve cover ? The block pulse fitting is really low is that why i get oil seepage? Here some pics of the fittings .

 

[125ccCrazy]

unfortunately yes... you will either have to mount the pump higher than the engine or tap the intake and use that pulse for the pump.... even mounting the pump higher than the engine you may get a little seepage from the oil mist in the pulse but you will get a lot more with it mounted below the pulse fitting...

 

[David wulf]

125 CC thank you very much for the info. I may try taping the intake .

 

[buckeye]

I read that you can put a fuel filter in the line to help. Not sure it is applicable to your issue.

 

[David wulf]

I read that you can put a fuel filter in the line to help. Not sure it is applicable to your issue.

Buckeye thats funny i was wondering if that would work myself . Might try it . Thank you very much .

 

[texasfabguy]

Just run a longer hose up then back down,the should be no reason for the oil to run up the hose unless you don't have enough venting for blow by. If it leaking it because of excess crankcase pressure.

 

[David wulf]

Just run a longer hose up then back down,the should be no reason for the oil to run up the hose unless you don't have enough venting for blow by. If it leaking it because of excess crankcase pressure.

Thank you for the advice . :thumbsup:

 

[125ccCrazy]

I had the same issue on a gokart a few years back with a brand new 13hp engine.... I always had oil dripping out of the vent on the pump and it was mounted higher than the pulse port so I tapped the intake and used that pulse, no more oil leak... any mist in the pulse will eventually build up in the pump and seep out..

 

[texasfabguy]

I had the same issue on a gokart a few years back with a brand new 13hp engine.... I always had oil dripping out of the vent on the pump and it was mounted higher than the pulse port so I tapped the intake and used that pulse, no more oil leak... any mist in the pulse will eventually build up in the pump and seep out..

I think you are blaming the location of the pump or the fitting,I do not believe this to be true. I used to though,But this is what I discovered.
The fuel pump diaphragm only moves about 1/8" .so on each stroke the pressure from the piston moving only sends a very short pulse in the hose then it stops at the end of the diaphragms stroke,the it returns on the up stroke of the piston. Now if you have excess crank case pressure it could lead to over working the diaphragm and blowing it out or make it leak. If that is the case you mite need a 2 nd vent.
The thing I do not like about a pulse taped into the intake is when you are full throttle it decreases pulse were as the crankcase is the opposite.