fuel pump

[steve allen]

does anyone know the pressure of fuel pump? What is the vaccum on the fuel inlet side?

[MSGT-R]

Mechanical pumps usually produce 2-4 psi. There should be no operational vacuum per se on the "draw" side since it's below tank height.

[WingAdmin]

There are different measurements depending on the engine speed. From the service manual, page 4-4:

2.4 psi at cranking speed
2.3 psi at 1100 rpm
2.0 psi at 5000 rpm

Volume: 450ml (15 oz) per minute at 3000 rpm, no pump load (i.e. outlet of pump running into a container)

As mentioned, there shouldn't be any vacuum at the inlet.

[MSGT-R]

Thanks for having the book (I'm at work). I was recalling theory from automotive experience. GM's operated @ 4 psi, imports slightly less.

[steve allen]

There are different measurements depending on the engine speed. From the service manual, page 4-4:

2.4 psi at cranking speed
2.3 psi at 1100 rpm
2.0 psi at 5000 rpm

Volume: 450ml (15 oz) per minute at 3000 rpm, no pump load (i.e. outlet of pump running into a container)

As mentioned, there shouldn't be any vacuum at the inlet.

is there an electric fuel pump I could use if I wanted to change for the old one?

[MSGT-R]

Yup, and all the details have been worked out:

http://www.randakks.com/Electrical%20Parts.htm

[piero]

I may have problems to perform a fuel pressure test on my 83 GL1100 but I can obviously perform a Volume test as clearly documented above in this topic. So..if the volume test turns out O.K., may I assume that the fuel pump is working fine?

Thank you - Piero

[WingAdmin]

I may have problems to perform a fuel pressure test on my 83 GL1100 but I can obviously perform a Volume test as clearly documented above in this topic. So..if the volume test turns out O.K., may I assume that the fuel pump is working fine?

Thank you - Piero

Correct. That's according to Honda. If it has enough pressure to push fuel through the hose at the volume specified, then it has enough pressure to fill the carbs at whatever rate may be required.

[piero]

Thank you so much! That's what I thought too but I wanted to check out with an expert!!

[OldguyGlen]

Here's an approximate test that might be easier to do in your driveway with limited equipment. And you don't have to rev the engine to 3000 rpm for a full minute. Get a 8ft clear fuel line and temporarily fit it to the pump outlet. While just cranking the engine, raise the end of the hose. See how high the fuel will rise in the hose. Some where in the 5ft - 7ft range is good. Temperature and altitude have some effect, but it is a quick and easy approximation test. Be careful about spilling gas around with open ended hoses. I'd do it outside.