Help!!!

I need to install a 4-stroke Magnum engine (.30) in the upright position because sideways or upsidedown, the engine will foul the steerable front wheel. However, this will put the fuel nipple and the high speed needle valve about 1" above the center line of the fuel tank. Will I be able to get enough fuel pressure to run the engine in this position.

I am going to use the pressure nipple from the muffler to pressurize the tank as well as the pressure nipple on the back plate of the engine. Is this too much? Can I use both of these fittings at once. The instructions which came with the engine did not even acknowledge the pressure fitting on the back plate. That is designed to ptovide pressure to the fuel tank...right????

Hope to hear from someone...Thanks...Mike

Is there any way you can raise the fuel tank location ? Perhaps "hog out" some of the formers to get the tank higher ?

If that is not possible, you may want to investigate either a "Uniflow" tank installation or the use of a pump.

DO NOT run the breather nipple on the backplate to the tank, it should be open to the atmosphere. It is a breather.

the crankcase vent nipple needs to be open to the atmosphere, as bhole said. Your engine will probably run ok, but the problem will be when you are trying to fly inverted. When inverted, your tank will be one inch HIGHER than your carb--therefore, fuel will siphon rapidly into the carb, and flood the enigne out. you will have all sorts of headaches until you get it right. I don't understand what you mean by "foul out the nose gear." How does the placement of the cylinder head affect the nose gear?

Thanks for all of the suggestions...particularly the information that the vent on the back plate needs to be open to the atmosphere. It makes sense, but there is no mention of this fitting or its purpose in the instructions which came with the engine. The consensus seems to be that the engine will run all right once it is started, but it will not be happy when the plane is flying upside down. At this point in my career, flying upside down represents a mistake...

Thanks again...Mike

When the tank/spraybar height relationship is excessive (spraybar higher) problems can manifest in a number of different ways. The first is it becomes difficult to get a run for the entire tank. As the fuel is used head pressure is reduced and this added to the fact that head pressure is already lower can result lean outs after a portion of the fuel is used. Another effect is when flying an airplane with low head pressure is when doing steep turns the added G load contributes to difficulty in getting fuel to the engine and tends to add to the the leanout condition so every time a steep turn is made with a good pull on the elevator the engine may stutter for a few seconds and come back up.

Finally nose high climbs may also result in early leanouts. These are some of the sysmtoms beyond what has already been mentioned that are the result of a poor Tank/spraybar relationship.


John

Yes, John brings up another great point. When I said you'd probably be ok, I should have said for a half of a tank or more. I forgot about that issue. I recently went through the same issue you have, so it's still fresh on my mind. I ended up having to mount my motor sideways to get a good tank/carb relationship.

Thanks again for the info...John and 2slow2matter have convinced me to re-engineer the front of my plane to solve this problem. I just spent 2+ hours removing my old motor mount...re-mounting my front landing gear...re-mounting the motor mount....all that is left is a new throttle cable mount and a new cowl...I guess I just figured out this time was a lot cheaper than re-building this particular crate one more time. I've already stuck it in the ground twice due to pilot error...and once because I ran out of fuel which caused a stall at a really inconvenient place...

Thanks again...Mike

Thats real good to hear Mike and I don,t think you will regrete the effort. When you get her going good how about posting about it. I am most interested in those little Magnum 30FS' because I,ve got a couple on the way for a twin Seniorita I just finished and have not used them before. By the way the nacelles are already set up for sideways mount


John