I have a situation with a model.I scratch built an aircoupe earcoupe whatever.In order for the engine to be in correct position for the cowl I turned it on its side and put the tank up as high as it will go.Not high enough I guess.So now it is starving and heating up lean.I have two perry pumps one new in box shakerand one red round pump that works off the engine crank case pressure it has an adjustment on it .I like that idea.
I read the instructions for the shaker and there is so many things you cant do.Its gotta be on the engine a certain way.do the shakers even work or should I try the older pump.This airplane
has been a total pain from the first stick of balsa.Oh well.does any one know anything about pumps.please let me know

I have the red Perry pump on a Webra Speed .40 with a tuned pipe. I can tell you that the pump works great! The Webra has a Dynamix carb, which doesn't have the greatest fuel draw (But big bore diameter for lots of power). I set my engine a tad rich on the ground, and it maintains a consistent needle setting during the entire flight. I have never had a sag because of the engine going lean. I don't have any muffler pressure coming off the pipe, so I know it must be the pump doing it's thing.

If your engine is running lean, then richen it up a bit. Or am I missing something here?

As a rule I tend to try to line up the top of the tank with the carb, not the centre line. Then it is a matter of tuning to that point.

The tank is so low compared to the carb its not drawing.I can almost take the needle valve out and it still leans out.I just put the engine on my new psp test stand.the best serious test stand out there .www.pspmfg.com check it out and see.it is worth the money.I'm going to see if maybe there is some other problem.I took the shaker pump out of the box and was totally alarmed when I read the instructions .It will not work on a test stand.That is so suspicious to me right off.It explains why but it makes no sense.do you drill and tap the back of the engine case for pressure.The red pump should work on the test stand it doesn't rely on vibration for pressure. my air coupe needs a test
flight

How does it not make sense?

The "shaker" pump relies on the engine vibrations to shake a little weight back and forth inside the pump. This weight is connected to the pump's mechanism. Really, it's a neat idea that appears to work quite well.

No engine is totally vibration-free. No engine mount is totally flex-free. It doesn't take much to operate the pump.

The shaker pumps work great. They can be mounted on the engine or the firewall inside or outside. The only important issues are the centerline of the pump must be at least 1 1/2" from the centerline of the crank and the pump must be mounted somewhere radial to the crank. That is to say as the engine shakes from side to side (not front to back) its motion will make the shaker inside the pump shake side to side (not front to back). They really are easy to mount and use. I have ran them on engines from 70 size to 180 size both 2 cycle and 4 cycle. I usually mount mine on the firewall under the engine but once when there wasn't room I mounted it on the inside of the firewall and it worked fine.

By the way, which engine are we talking about here? You haven't said.

Also, what exactly do you mean by "leans out"? Is this when running on the ground, and as the fuel level drops, or is it when you point the plane to the sky?

There may be other issues here, such as length of fuel line, bore of fuel line, cink in fuel line, bubbles in fuel line etc. Have you checked these.

The engine was a brand new webra speed 40.I have looked at all the things you mentioned and more.The only thing I can find is the tank is too low.Its either invert the engine or use one of the pumps I have .Im gonna try the red one because it better lends itself to my mounting situation.Thanks guys another point of view always helps.guess what this one is, scratch built in 1970
still flying today.have a great day flyyboy

What carb is on your Webra? Is it the TN (two needle) or the Dynamix (slide valve)? I know for a fact that the Dynamix does not have very good fuel draw. Also, with the Dynamix when tuning the low speed needle, you turn the screw OUT for LEAN and IN for RICH. Lots of guys have overlooked this little fact and pronounced that the Dynamix is garbage. Nothing is further from the truth. It is a high performance carb, and the Perry Pump really helps deliver the fuel. I have had mine set up for over 10 years with never a problem. Just a great idle, and instant acceleration to screaming full throttle.

I really like the dynamix as well.I have it on my 61's this is a tn
.The engine runs super in the test stand .I have it totally dialed
in.Choke two turns one flip,starts and idles super every time.I'm going to use the red pump first.The adjustment on the pump is
clockwise less counter is more is that right .have a great day guess the model very super popular in the
late sixties early seventies