Hi
I have set up a Gret Planes Extra300S Paty Wagstaff with a Moki 2.10 in line with the earlier published PRODUCT REVIEW
by Jim Feldmann on Great PLanes website.
I can't get the engine to idle properly in air. On ground it's OK but after flying for 5 minutes a can't almost land the plane it stays about 2500-300rpm wich is too much. Tank is 18" from carb, using Perry VP30 pump, Bisson Pitts large volume muffler.
All ideas are welcome!

Can the throttle barrel close all the way? Try move the low speed disk a tiny bit towards the + sign, move it very small amounts its very sensetive.

Try bumping the throttle stick up a few times before starting your turn for final approach. It will usually knock the idle down. I've seen this on my Perry pump with Moki 1.80. You can usually bump the idle trim down a few clicks as well. I believe this is caused by the engine idle going lean since it's at the end of the tank. If you bump your throttle trim down a few clicks it will usually be too low when you refuel and start the engine again (because it's rich). I don't have this problem with my Moki 2.10 and Cline regulator. Do a few approaches trying what I recommended to see if it works (but don't actually land). There is also a idle down mix on the Futaba 9C that can be used for this but I never tried it. It uses a switch to go to lower idle. After a while you will get the routine down. I see this on my YS 63 as well (idle changes from full to empty tank).

Had the same problem with my Moki 210 and hanger 9 cap. Leaned the lower end one eighth of a turn. Do not move it very much as it is very sensitive.

Put the tank behind the firewall and get rid of the pump.

Marc 540

I'm now bypassing the Perry pump and trying to run the engine with the tank approx 12" behind te carb, using muffler pressure. The Moki dealer tell me it should work! Let's find out, I'll be back for reporting as soon as I have tried it!

If I put the tank behind the firewall, how does Patty react with full versus empty tank, moving CG back and forth!?? Any experience??

That's pretty far back, it will probably flame out on up lines or hovering. You will need to run it very rich. Also you should set the high needle on the ground with about 1/4 full tank. This insures that you don't lean out at the end of your tank while you are flying. I'd personally keep the pump and move the tank up.

You will be very nose heavy when your tank is full. Also your CG will move forward from moving the tank forward even when it's empty.

I haver tried to run with muffler pressure (tank 12" behind the carb). Needle 4 1/2 turn out. OK with half and full throttle but too low pressure at idle, the Moki stops. I now feel tha I have two options;

1-block one of the pipes on the muffler,
2-move the tank forward behind the firewall and go woth the manual.

Both cases means taking out the Perry pump.

Ideas please................!

not bashing the perry pump. but a cline regulator will solve you problems. just send it to jim and itll run when you get it back lol

I totally agree. I just went through the same thing as you with my Moki 2.10. The perry pump simply did not work with a tank 20 inches back on mt DPM Edge 27%. I used the Cline and it works flawlessly. I would keep the tank on CG and try the Cline or Ironbay fuel regulator. Make sure to use a good filter (Dubro) before the regulator and it will be very reliable. The plane will fly much better with the tank on the CG since the CG is the same for entire flight. With the tank in the nose it will be very nose heavy for the beginning of the flight and be perfect only when you are ready to land. Also the engine will run with the same exact mixture the entire flight instead of leaning out as the tank gets empty. You will use less fuel as well. That is a fact.