need help old motor guys

[vwluv32]

I was pulled the fuel pump off of a 63 75hp starflite and was wondering if it worked off of pressure or does it work off of vacuum? The pump has 3 nipples, one says fuel in, one says fuel out, and the other one says pressure, so I was wondering. Thanks,
Chris

 

[JB]

Re: need help old motor guys

The "pressure" is connected to the crankcase, where alternating pressure/vacuum is used to operate the pump.

 

[vwluv32]

Re: need help old motor guys

Does this mean I can use it for the fuel pump on my 57 18hp? Does it have to run off of the bypass cover or can I use the pressure nipple that fed the twin hose system?
Thanks,
Chris

 

[JB]

Re: need help old motor guys

Never thought about that. What have you got to lose?

 

[tootallofwa]

Re: need help old motor guys

Does this mean I can use it for the fuel pump on my 57 18hp? Does it have to run off of the bypass cover or can I use the pressure nipple that fed the twin hose system?
Thanks,
Chris

I'd go with the bypass cover, That's how my 62'28hp an 63'40hp are fed.

 

[1946Zephyr]

Re: need help old motor guys

NO!! Do not use that to power a fuel pump, because fuel mix sprays out of there. If you're converting your motor to a fuel pump, you need to run an actuator line off of your bypass cover, like all the motors come factory with.

That little nipple on the bottom of your manifold should be removed and replaced with a plug, with the same thread. Some people plug those off, but if that plug pops off, you have a huge fire hazzard and risk blowing the engine shroud off and launching it across the lake.....seen it happen.

Fuel pumps on these old motors are like wood stoves. Only half the people out there get 'em right and they end up with big problems.