Small engine carb question

Dec 21, 2003 5 Replies

Hope this isn't too off topic.



I'm planning on converting an old snow blower (8 hp Tecumseh 4 stroke) to a start/light cart (auto alternator, battery charging and head light array). I want to replace the stock gravity feed gas tank with one of a gallon or two capacity and to do this I will need to relocate it.



Would there be an issue feeding the carburator using a generic "after market" automotive 12v electric fuel pump? I'm not sure of the output pressures generated and I'm concerned as to whether or not the carb will handle it.



Thoughts or comments?



Thanks in advance



BT


If it is a typical Tecumseh carb (float bowl and needle on the bottom) then it isn't designed for pressure beyond the minute one created by gravity feed. The needle valve operated by the float is incredibly delicate in these anyway and pumped fuel would rush through if pumped. Why can't you simply gravity feed from a larger tank? This is pretty commonly done on standby generators.

How much more gas do you need? Seems like a snow blower engine, don't they have most of a galon?

One other thing to mention is that the gas consumption depends on the load. If you're running a relatively light load, the gas lasts a lot longer. I'd stay with the stock tank for now.... play with modifications later after you get the generator head wired up and everything else.

Water has a "head" of .434 PSI per foot of lift, and gasoline is less than that. I'd guess that any fuel pump would over pressure for your use.

Think I'll stick with the gravity feed. My initial thoughts were in regards to the new tank size and space needed to mount the alternator.

Thanks for your input!

the important thing to mention is that techumseh snow king engines are baffled differently for cooling since they run in winter. something to consider before you cook one. Chip

If your looking for more capacity, mount the larger tank remotely then add a supply and return line to the existing tank. That way your pump will feed gas to the tank and you will keep your existing gravity feed system. You will probably have to throttle the flow from the fuel pump and upsize your return line to keep from pressurizing the smaller tank.

Nate

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