Im building a giant P-51D from Top Flight and I havent fired the fugi imvac 64A as of yet. I wondering what is going to supply fuel pressure to the carb. It appears that the carb sets above the bottom of the fuel tank, actually it sets near the top of the fuel tank when the plane is setting level. What will supply pressure to the carb? This engine runs mixed fuel. Basically a weed eater engine, but weed eaters are gravity fed, which just doesnt seem right for a plane that goes inverted.

Thanks,

Jeff

The carb has a pump in it.

Weedeaters and chainsaws are not gravity fed. The carbs have a pump that operates from crankcase pulsations. The carb will pull fuel from the tank with a very strong without any outside help.

This is a 2-stroke engine which uses a gasoline/2-stroke oil mix. The carb is probably a Walbro type. It has an internal diaphragm which operates from crankcase pressure through a port in the manifold. This pressure/diaphragm actually pumps fuel into the engine. Gas tank position is NOT critical, and no gasoline tank pressure is required.

Weedeater engines are not gravity fed. They utilize the same pressure/diaphragm system I just described.

Dr.1

Now theres an answer I can go with. After looking into the carb and talking to Fugi I am alot less worried.

For the record, my weedeater (craftsman) 32cc, wont run upside down.

Thanks for the answers...

That's interesting about your Craftsman weedeater. Don't know why it won't run upside down. It should. Not to worry, your Fugi will run in any position.

Dr.1

The only reasons for it not to run upside down is that the fuel pick up tube is not moving freely in the fuel tank, or the fuel level is low, or you have cracks in the fuel pick up tube above the level of fuel when it is inverted. Otherwise, it should run in any position.

I've seen in some weedeaters that the fuel pickup is simply at the bottom of the tank only. There isn't enought tube to move to the top of the tank when it's turn upside down hence it won't run.

what kind of 2 cycle oil should i use,instead of the fuji brand,?where can i buy?

Any good quality air cooled 2 stroke oil in an appropriate mixture for the OIL will suffice.

That could be a conventional chainsaw/weedeater oil at 32:1 (that's what I use), to a synthetic voodoo oil at whatever ratio they recommend. Properly tuned, even 32:1 conventional oils will result in minimal buildups and minimal cleanup.

I get mine at Canadian Tire, or the local gas station. That there is appropriate oil, and enough of it, is key, not exactly what type you use.

Oil questions are religeous in nature. Many opinions, little proof (except not enough sucks).

Do your engine a favor and tune it properly when you're ready to run it. Like a glow engine, a gas engine is not tuned from the factory. You will not need to tune it nearly as often as a glow engine, though. A couple times a season work for me.

J