Need help id-ing missing part from Magnum Pro 45

Right hand side looking forwards? My guess is the throttle stop screw. I have had only one Magnum 2 stroke (POS) and I recall it had a spring loaded screw in the front right of the carb. This adjusted the limit of the throttle closing.

Matt- It's the throttle stop screw. It limits the travel of the carb rotor at the low end of the speed range, and also keeps the rotor from sliding out of the barrel. It simply isn't necessary as to the idle stop function, as you can set the low throttle stop with the radio/linkage end point adjustment, as is the general practice. Put in a screw with threads filed off the end (must be a sliding fit into the helical groove in the rotor) for a couple of mm to stop the fuel leakage and retain the rotor. I think it is 1.5 or 2mm, but to be sure and to restore its intended function, you can get a replacement part from Thundertiger (represented by Ace in the US), the OEM for that engine. Not be confused with the current Magnum engines made in PRC. Hobby People owns the Magnum name, but the engines currently sold by them are not the made-in-Taiwan by TT engines like yours.

Abel

Oops, forgot to mention the third function - it guides the lateral motion of the rotor, which is 'programmed' by the helical slot, which controls the position of the low speed needle in its seat, which meters the low speed mixture - lot of work being done by that little screw! Afterthought: if the rotor doesn't pop out the right side of the carb, something must be be keeping it there, and subject screw is the only thing that would. Leads to suspicion that stub of it is still in there, and the head of it has been sheared off by overtightening a lock nut.

Abel

Hi,

No, it's on the right-hand side looking back toward the tail of the plane. The carb has what I believe to be the throttle adjust screw on the left-hand side, above the throttle control arm.

Could the missing part be some kind of idle adjust?

---Matt

Matt- Now that you've clarified which right-hand side, some other things are a bit muddier..... You said Magnum Pro, but the carb sounds like what comes on the Chinese made Magnum XL. If that is so, then the missing part is an idle stop screw, which had a compression spring on it to increase friction and keep it from falling out......which apparently didn't work. The other one, on top on your-defined left side, retains the rotor in the barrel. Carbs for most engines have one screw to perform these functions - I have no idea why the designer of this carb felt the need for two.

Abel

I figured it out! I got my hands on a photo of a NIB Magnum Pro 45, and the extra hole my carb has is distinctly missing in the photo. My guess is that someone drilled and tapped the hole, but for what purpose, I have no idea. My plan is to plug it with a machine screw, and carry on.

Well, the block says "Magnum Pro 45", but it's entirely possible that the carb is a replacement from another engine.

Thanks! That makes sense -- a lot more than my original conclusion, in fact. : Any idea where I could find a replacement? The manufacturer has already told me that they can't help.