Moki 2.1 Tuning Help
03-16-2008 | 09:25 PM
#1
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From: ramsey,
NJ
Moki 2.1 Tuning Help
I have 5 Moki 2.1's and 1 Moki 1.8. Love the engines, but I developed a problem with one of the engines.
It had 5 gallons run thru it for break in before mounting in the plane. Nice Idle and great top end. However,
the transition and midrange is terrible. I just cant figure this one out. It seems that no matter how I adjust
the motor, I am not "hitting" the right settings to get a smooth, reliable transition. It seems that the midrange
has very little variation between throttle settings. The low speed wheel is in the stock position and I adjust the
HSN for max, minus about 300 rpm, which gives me a nice smoke trail and reliable power. My son began
doing 3D with it and noticed the problems.. Any ideas?
It had 5 gallons run thru it for break in before mounting in the plane. Nice Idle and great top end. However,
the transition and midrange is terrible. I just cant figure this one out. It seems that no matter how I adjust
the motor, I am not "hitting" the right settings to get a smooth, reliable transition. It seems that the midrange
has very little variation between throttle settings. The low speed wheel is in the stock position and I adjust the
HSN for max, minus about 300 rpm, which gives me a nice smoke trail and reliable power. My son began
doing 3D with it and noticed the problems.. Any ideas?
03-17-2008 | 07:19 AM
#3
Senior Member
RE: Moki 2.1 Tuning Help
The low speed wheel is in the stock position...
I agree with Skiman about your 'break-in' being excessively long...
What determines the transition is the position of the fuel metering valve, which in the Moki's case means the rotary low-speed fuel control. If the engine cannot transition properly, with that control in the stock position, you must change it to a different position that will give you a good transition.
It is a simple as that!
How far is the fuel tank back from the carburettor?
You might need a pump/regulator, if it is not smack against the firewall...
03-17-2008 | 12:03 PM
#4
Senior Member
My Feedback: (3)
RE: Moki 2.1 Tuning Help
ORIGINAL: overpower
I have 5 Moki 2.1's and 1 Moki 1.8. Love the engines, but I developed a problem with one of the engines.
It had 5 gallons run thru it for break in before mounting in the plane. Nice Idle and great top end. However,
the transition and midrange is terrible. I just cant figure this one out. It seems that no matter how I adjust
the motor, I am not "hitting" the right settings to get a smooth, reliable transition. It seems that the midrange
has very little variation between throttle settings. The low speed wheel is in the stock position and I adjust the
HSN for max, minus about 300 rpm, which gives me a nice smoke trail and reliable power. My son began
doing 3D with it and noticed the problems.. Any ideas?
I have 5 Moki 2.1's and 1 Moki 1.8. Love the engines, but I developed a problem with one of the engines.
It had 5 gallons run thru it for break in before mounting in the plane. Nice Idle and great top end. However,
the transition and midrange is terrible. I just cant figure this one out. It seems that no matter how I adjust
the motor, I am not "hitting" the right settings to get a smooth, reliable transition. It seems that the midrange
has very little variation between throttle settings. The low speed wheel is in the stock position and I adjust the
HSN for max, minus about 300 rpm, which gives me a nice smoke trail and reliable power. My son began
doing 3D with it and noticed the problems.. Any ideas?
Have you tried installing a carb from one of the others on a process of elimination?
03-17-2008 | 01:31 PM
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From: ramsey,
NJ
RE: Moki 2.1 Tuning Help
Thanks everyone... I have never had to touch the low speed wheel on ANY of the Moki's.. I just never considered it. I will try later today. BTW, Although the 5 gallons may seem a bit excessive, there wasn't much flying going on over the winter, so I ran it as often as I could for the breakin.. I was just trying to be thorough in my description. We usually run about 2 gallons thru the new motors before a maden flight, but this one was an exception. Thanks again.. Will let you know the results.
03-17-2008 | 02:03 PM
#6
Senior Member
RE: Moki 2.1 Tuning Help
ORIGINAL: overpower
...I have never had to touch the low-speed wheel on ANY of the Moki's...
...I have never had to touch the low-speed wheel on ANY of the Moki's...
Unlike late '80s carburettors that had tamper-proof low-speed mixture control screws, the idle adjustment in model engines is an essential control that must be adjusted.
It controls the fuel curve over the bottom 70-80% of the throttle range.
Changing the prop, the plug, the fuel, the altitude and even the weather (well, that changes on its own...), will require a change in the setting of both fuel controls (or all three in applicable engines).
The necessity to make changes to the low-speed fuel control; despite what many people seem to think, does not mean anything is wrong with your engine!
If you never had to make any change until now, the factory setting was simply close enough to ideal, for the specific conditions you (and your son...) fly in. Call it luck!
If it was an OS, you would most likely had to close the low-speed control a greatd deal, for your engine to tun right.
06-21-2008 | 03:45 PM
#7
RE: Moki 2.1 Tuning Help
Found this thread after a search...
I ordered a Mark 2.10 for my H9 Sundowner...
What do ya think would make a fast prop for this combination? I'm going to run a Bisson Pitts style muffler...and all out max is not what I'm looking for, but I want the most pitch I can reasonably run...
I'm thinking maybe I will try the 16 X 14 APC, because I already have one...sound reasonable?
These things are supposed to run on no or low Nitro too, correct?
I ordered a Mark 2.10 for my H9 Sundowner...
What do ya think would make a fast prop for this combination? I'm going to run a Bisson Pitts style muffler...and all out max is not what I'm looking for, but I want the most pitch I can reasonably run...
I'm thinking maybe I will try the 16 X 14 APC, because I already have one...sound reasonable?
These things are supposed to run on no or low Nitro too, correct?
06-21-2008 | 10:04 PM
#9
RE: Moki 2.1 Tuning Help
Thanks...
I know that it's not a revver...I plan on loading it with pitch to keep the r.p.m. in it's "happy range"...if it will swing the 16 x 14 in the 8,000-9,000 range I figure that should be OK.
I don't really have ground clearance for larger than an 18" dia. prop anyway.
Guess I'll haveta find out fer myself ?
I know that it's not a revver...I plan on loading it with pitch to keep the r.p.m. in it's "happy range"...if it will swing the 16 x 14 in the 8,000-9,000 range I figure that should be OK.
I don't really have ground clearance for larger than an 18" dia. prop anyway.
Guess I'll haveta find out fer myself ?
