Fuel pump strength on 6hp and 9.8hp 4 strokes

[simplystressed]

Does the fuel pump on these models have enough strength to tie into an under floor gas tank? I'm thinking of scrapping the portable tank and tying into my main tank, but wasn't sure if the longer run and gravity would play a part with these smaller motors' fuel pumps.

thanks

 

[pvanv]

Re: Fuel pump strength on 6hp and 9.8hp 4 strokes

You can lift about 3 feet no problem. Also, the newer pumps are improved over the originals. In some cases, I have seen the primer bulb sucked flat when the tank went was inadvertently left closed. Plenty of suction for most installations. More vertical lift causes more vacuum in the system, so make doubly sure you don't have any potential leaks that would allow air into the hose (such as an incorrectly/inadequately tightened water separator). What is your model/serial?

 

[simplystressed]

Re: Fuel pump strength on 6hp and 9.8hp 4 strokes

You can lift about 3 feet no problem. Also, the newer pumps are improved over the originals. In some cases, I have seen the primer bulb sucked flat when the tank went was inadvertently left closed. Plenty of suction for most installations. More vertical lift causes more vacuum in the system, so make doubly sure you don't have any potential leaks that would allow air into the hose (such as an incorrectly/inadequately tightened water separator). What is your model/serial?

ok thanks pvanv. Mine is an A3 2007 model - the under floor tank is open vent, so sounds like I should be OK or will at least keep an eye on things if I switch over. I can actually use the existing hookup for the main as a test, I'll give that a whirl to see if it causes any issues before getting the 3 way valve extra lines etc

 

[pvanv]

Re: Fuel pump strength on 6hp and 9.8hp 4 strokes

The MFS 4/5/6 fuel pumps (also fit the MFS 8/9.8) were upgraded in 2003 or 2004, so you should have the more robust pump. Be sure that you have primer bulbs (with check valves) for each motor, downstream of any T fitting in the line (or put a 3-way valve in the line), so that one motor doesn't suck the fuel out of the other, resulting in drawing air. Remember, if using a larger tank, that you don't want to get into using fuel more than a month old. You may want a water-separator on that rig as well.