What do I need to do to swap a fuel pump to a gravity fed one?

I'm thinking of swapping my pump fed opposed twin into a gravity fed mower. Since the same motor came in gravity fed configuration I'm sure it's possible but I'm very new to small engines. So what exactly would I need to do? Pull off the pump obviously.

why would you rather have it gravity fed? cause if you do then you can't hillclimb cause as soon as the carb gets higher the engine cuts out...

Yeah, I'd stick with the fuel pump, although pretty lame, they get the job done. Most of the time.

Well, I read where someone had a pump, but they ran a tank higher than the carb, and it had flooding problems. So it's either move the fuel tank somewhere else, or switch to gravity feed. I'm not opposed to the pump, especially since I rebuilt it last week. I just want it to work properly though.

Id stick with the pump too - those twins are hungry for fuel - i dont think a gravity fed tank would work that well. Most my twin cylender pumps have never been rebuilt and still work great. A good way to see how much fuel is flowing to the carb: use a short piece of clear fuel rated tubing - its probably a good idea to replace those old rubber fuel lines anyway - they do detiriorate over time and can clog or contaminate the fuel going into the motor.


The majority of my twins use the carb mounted fuel pump - however my 18HP opposed horizontal has this huge vacuum fed fuel pump on the plate that mounts behind the motor- that tank is running from the back of the tractor and really needs it.

That sounds like the pump on my twin, vacuum operated and tank under the seat. So if I swap this motor into a mower with the tank under the hood, will it still run right, not flood?

Should work fine- my hydro murray's tank is under the hood and still uses the pump - so's my MTD with an 18.5HP twin - had my modified 94 murray with the 18.5HP opposed on it- same setup- ran awsome- and fast!

Oh good, that makes things a lot easier. Now to find a tank. The stock one is missing. I suppose I could always make one from sheetmetal if I could find something good for a filler and cap.

a good idea i saw was to buy a plastic filler can like this;

then just tap a hole in the bottom and make it water tight, then when you need to fill it you could take it off and fill it! simple

Yeah, Ive always wanted to use a 5 litre gas can for a fuel tank.

That was me who had the flooding problems. It was stuck float, which coincidently happened right after I had the fuel tank mounted up above the pump. Shear conincidense though. You should be fine running it like that.

Cool, good to hear. I only remember about half of what I read, haha. The gas can is a great idea as well. What type of sealant/adhesive would you guys suggest for the barb fitting at the bottom to attach a fuel line? Needs to seal tight and hold up to fuel.

put a pipe in and use silicon, if you don't want it to move later

redneck solution's fae DUNC

RTV sealant m ight work, cant rembmer if that holds up against fuel though.

My immedate thought was becuase it was mounted up high, because that was the only thing that had changed for the test run. Through me off. It had no filter on it, and I guess it just had crap in the line. So theres another lesson for you, even if you're just test running something, use a filter! lol. Could save you a head ache.

Absolutely, filters are there for a reason. I was helping a neighbor get their push mower running the other day. No filter, left outside in the rain. Turned out to have a blockage in the fuel line too, which under compressed air shot through the garage like a BB. Lack of maintenance amazes me. Stuff costs too much to just let go like that.

I know, but without your average "Harry Homeowner", and people having too much money, I wouldnt have most of the machine I do!

Dont use RTV - a bolens i got from my wifes step brother ( redneck engineered the crap out of it) - he mustve cut the tank with a grinder- was a narrow cut near the bottom- he plugged it with RTV ( unbeknowst to me) and after i filled it half full with gas- i wondered why the next day it was empty.


Id say use an epoxy or if youre drilling a slightly tight hole ( need to thread it thru the tank) use a gasoline proof rubber gromit on both sides and put it near the opening to put a retaining nut on it.


Yeah its amazing what people do to save money when working on tractors - ive had alot of them - my 84 dynamark- the guy welded the front deck bracket to the deck and welded the one cracked side at a weird angle as well ( crappy weld also) - my 99 weedeater had seized spindles and no deck blades - my 90 task force had hob jobbed wiring but oddly enough i drove it home around the corner- to name a few.......usually i make sure the motor runs, then look at how much itd take to fix it , then decide to fix or parts it - another thing that makes my mind up is if i like how it looks- then it doesnt matter- it comes apart and i go thru the whole thing.