spraying fuel vent hose ?

An "old timey" solution would be to place a small piece of fuel tubing cut at a 45 degree angle facing forward on the offending vent. Air pressure from the prop wash should keep the vent from spraying.

SD

It's def connected with tubes the wrong way round.
I bet your tank is upside down and your 'filler' is really
Your fuel line with the clunk on the other end.

Ken Cook wrote: My first question would be is this engine in a plane or on a test stand?. Not that it would be directly related but your post is quite vague in terms of defining the problem. Is this in a R/C configuration or control line? Are you using a hard metal tank or a plastic R/C tank? I ask this due to seeing plastic tanks filled through the incorrect vent in a control line configuration and they swell up and then fuel spurts out from the other pipes as the pressure is relieved. The only other reasoning for fuel to be spurting out of the vents is in the event your running muffler pressure and your other pipes aren't capped off properly. This shouldn't be related to the engine. Are you using a muffler with muffler pressure? Ken

******** yes in a r/c plane ,plastic tank capped off i don't understand i have never capped off any line that i remember.. i will look at some other planes i have and see i think there still intact sorry for the short was a long day hauling fire wood yesterday

There are a number of different fuel system schemes. Some use pressure, some do not. Some require caps on certain tubes.

Do you know how your fuel tank is set up? Can you remove your fuel tank from the airplane to inspect (without heroic efforts) it or is it sealed into the airframe?

Assuming a clunk type fuel system

If you have a 3 line system you can use some fuel and a fuel ball or syringe to work out the scheme. With the aircraft upright partially fuel the tank. Close off one line, apply pressure to another and see if fuel exits the 3rd, or not, note your results. Switch the lines and record results.

Then invert the aircraft and repeat.

If the tank is a clunk tank the clunk will keep fuel coming out of the same line each time.

If it is a uniflow clunk tank then there will be 2 lines that fuel comes out of in both positions. One is the pressure line, the other the feed line (it shouldn't matter which). The 3rd line gets capped as it should be a solid vent to the top of the tank while upright. You can choose different operation schemes in this configuration.

If it is a 3 line tank with a fill, vent, and clunk, then the clunk line is the fuel feed, and should pickup upright or inverted. The other two lines can be to different locations, but the one that seems to only draw from the very top of the tank is the vent, which is where pressure should be hooked up to, the other line is to fill and if running pressure should be closed off.

If it is a 2 line tank then the vent is the top of the tank, you fill through the fuel feed by disconnecting the engine. There is no 3rd line. The vent line can be left open or hooked to pressure.

Using pressure will change your needle settings.

If running pressure on a tank with the 3rd line open pressure won't work properly, and it will likely spray fuel.

Phil