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Magnum 91 4 cyc (XL91RFS)

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Old 08-14-2017, 03:40 PM
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billinpa
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Default Magnum 91 4 cyc (XL91RFS)

Hello 4 cycle guys! I just acquired an older Magnum XL 91 RFS, little use, very clean. There are two nipples on the muffler, one is the pressure tap the other is a dummy nipple, doesn't have the hole all the way through. Strange. It has the usual nipple for the inlet on the needle housing plus another functioning nipple on the intake pipe above the carburetor going to the cylinder head. It has the customary crankcase vent nipple as well. I'm only speculating, should I run a length of fuel tubing from the intake pipe nipple to the dummy muffler nipple to close the system? Why is the nipple on the intake manifold pipe in the first place? The instructions show the breather, fuel inlet and pressure nipples, not the dummy and the manifold pipe nipples! I'll run it up before mounting on my 81" J-3.
Thank you very much in advance for any information you can share!

Bill in Pennsylvania
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Old 08-15-2017, 01:40 AM
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Could be he used the intake pipe nipple to prime the engine and the other end was on the close nipple to seal the system, you'll want to close off that nipple somehow,, yes

The only reason I can imagine for the closed off nipple was for could be the guy moved the muffler pleasure line to that to prevent fuel other from spilling out the tank when working on and or transporting the plane. When you have a plane that needs to be upside down to mount/remove the wing, a little fuel dribbling can be an issue.

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Old 08-20-2017, 02:45 PM
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The only reason I can imagine for the closed off nipple was for could be the guy moved the muffler pleasure line to that to prevent fuel other from spilling out the tank when working on and or transporting the plane. When you have a plane that needs to be upside down to mount/remove the wing, a little fuel dribbling can be an issue.
Interesting thought Scale Only 4 Me! Now I wish I had one!!!!
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