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MOKI RADIAL Care and Maintenence

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Old 07-21-2018, 06:03 AM
  #4126  
chapi07
 
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here in my country we use to buy fiala propeller that gives a good sound to the 2T engines

Could something say whats the better propeller for the P47 meister scale 102" and this moki180??

Moki recomend the 28x16 for genral purpose and 26x18 for warbirds

I am thinking about a 26x14 ...what do you think??
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Old 07-21-2018, 07:27 AM
  #4127  
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Not sure if this has been mentioned before?

Has anyone run a Moki radial, specifically the 150, without the exhaust collector ring? I am looking at a project where space is limited so I am looking at doing away with the ring and running individual exhaust stubs.

Cheers!
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Old 07-22-2018, 06:37 PM
  #4128  
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Default Moki 150 RPMs and Plug Condition

Did some test runs this weekend to get a feel for the motor's operating range.

I'm seeing around 900 rpm idle and about 5100 max with a 26x16 prop on the test stand. Is this idle about right for this prop? I'm seeing others mention 600rpm, but not sure if thats what I should expect on the 150. Seems to be a pretty smooth transition from idle to full throttle, and only a couple of puffs of white unburned fuel from the #3 exhaust side of the collector ring when the engine hasn't warmed up. After running a few minutes the puffs of unburned fuel seem to disappear and it seems to smoot out.

Plugs seem to be showing black build up after only a couple of tanks worth of running, except for the #3 which comes out wet with fuel and with no discoloration or buildup. I'm not sure #3 is firing, but I assume it is due to the visible puffs of fuel disappearing. The #3 cylinder is noticeably cooler than the others, but I haven't checked their actual temp. I can touch #3 by hand, whereas the others are too hot to touch after killing the engine.

The #3 side of the collector ring is still throwing black oil pretty heavy. The other side(pilot side) of the ring has all but cleared up on any messy exhaust. I'm running redline at 50:1 plus 2 ounces of Seafoam per gallon of fuel. I've just started running the seafoam.

I'm running on a CH Ignitions with a 7.4 battery.

This is all after the adjustment of the valves to factory settings. No turbulator yet, and I'm wondering from these conditions if it's worth going through the paces with trying it. My biggest reservation is that it looks as though the turbulator would require some engineering to get the servo's for throttle and choke to be easily accessible, as the carb will protrude into the firewall of the plane (CY models LA-7). This will also make any carb adjustments more difficult to perform without engineering a hatch to get to the carb.

Thoughts and suggestions would be appreciated.
Mike
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Old 07-30-2018, 06:44 AM
  #4129  
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Did some testing with and without the turbulator this weekend and saw no real repeatable difference in the running of the engine. I did have one moment of better running when I turned the vanes inside the turbulator. Everything seemed to smooth out to a degree, but it appeared that the vanes were loose when I removed the carb for further adjustment. By loose I mean that I could turn the vanes a 1/4 turn clockwise but they wouldn't lock in place. Not sure if there's a way to safely secure the vanes once adjusted.

With and without turbulator my midrange gets a misfire with white puffs of smoke. Full throttle seems to smooth out and Idle seems pretty smooth with rpm's ranging from 850 to 4090 with the SEP 24x18x3 prop. I'm thinking about just bolting it up and not tinkering any further.

One question about this prop and RPMs, is ~4000 rpm suitable on this prop? I'm installing the motor on a CY LA-7 and later will put it into a Ziroli Corsair.

I also switched to Amsoil Dominator as Gotz suggested I immediately quit using Redline. He stated that they have had lots of repairs attributed to using Redline.

I'm still a radial noob, so any feedback and guidance would be greatly appreciated.

Thanks,
Mike

Last edited by bigmikew; 07-30-2018 at 06:46 AM.
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Old 07-30-2018, 10:20 AM
  #4130  
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Hello Mike,
Which dominator? 50:1?
Thanks,
John

I also switched to Amsoil Dominator as Gotz suggested I immediately quit using Redline. He stated that they have had lots of repairs attributed to using Redline.

I'm still a radial noob, so any feedback and guidance would be greatly appreciated.

Thanks,
Mike[/QUOTE]
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Old 07-30-2018, 11:06 AM
  #4131  
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Default Amsoil dominator

50:1 Amsoil Dominator or Sabre is what he recommended. I bought the synthetic racing dominator.
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Old 07-30-2018, 11:41 AM
  #4132  
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Hey Guys, I have a Moki 250 5 cyl I'm trying to figure out the typical used price range for this motor, I normally google this and check past sales, but they have all been erased

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Old 08-01-2018, 10:35 AM
  #4133  
David Jackson
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Where in the USA can I get a Moki 250 serviced?
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Old 08-01-2018, 11:32 AM
  #4134  
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Contact Vogelsang Aeroscale. They service Mokis.
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Old 08-02-2018, 07:06 AM
  #4135  
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Moki service.

JM Engineworks
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Old 08-05-2018, 07:23 AM
  #4136  
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Lately I have been seeing posts concerning RedLine oil usage. One of my 215's has 200 flights and the other is approaching 300. The engines have excellent compression, run in the 180 degree range and no valve sticking. Now I do mix 44;1 and rarely run the engines at full throttle. Can anyone tell me what the damage or failures are that are associated with the use of this oil. I am willing to stop using it if there are valid reasons. -Tom
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Old 08-07-2018, 11:50 AM
  #4137  
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Hopefully we can avoid an oil war here, as this is mostly a emotion-driven subject.
I too have been running Redline 2-stroke racing oil in all my gas engines for 10 years now. This includes a Moki 250 with well over 250 flights on it. I run a 50:1 mix and have NEVER had a oil-related engine failure. My sample includes:
Moki 250, 3W 170, 3W 150, DA-50, DA-85, MVVS 80, G38, G62, and G26. I also break my engines in on Redline for what that's worth. In my oil studies over the years I came across a very in depth study by Ken (Big Bird) and one of the takeaways from his extensive testing was some oils contribute to the combustion process and some oils do not. One of his conclusions was "...the amount of carbon in an engine seems to be related to the quantity of fuel burned for a specific oil brand." I know from first hand observation that Amsoil use results in more carbon deposits than Redline. I do not have the knowledge to say that's good or bad, but personally, I want to minimize carbon buildup in my Moki. With that said, I offer the following picture of one of my Moki cylinders. This is the engine with more than 250 flights on it:


Sorry that image turned out so huge. We are looking at this because I stuck my Moki into the ground on the nose of my CARF Corsair last year.
Anyway, this is my oil story and I'm positive others will have first hand observations to support their contention. But as to Redline being bad for your engine...not in my experience.
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Old 08-08-2018, 04:17 AM
  #4138  
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Greg, thank you for your response. My experiences with Amsoil was similar, with carbon buildup and sticking valves. The valve problem was so bad that I was close to writing Moki's off my list. This was several years ago. Now at that time I was not using seafoam, which adds a variable to the situation. (1 oz/gal) I have no emotional attachment to any oil, I want what is best for the engine. -Tom
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Old 08-08-2018, 06:15 AM
  #4139  
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Unhappy Moki 150 - oil and other questions

Some of the contradictory advice makes it difficult for new-to-radial users, like me, to know which is the best direction to move in. I'm not attached to any oil, but would like to know that I'm running a clean, safe oil in my engine. Sounds like redline runs cleaner, but Gotz is saying to immediately cease using it in favor of Amsoil Dominator or Saber.

A couple of questions for those who have more experience with these engines: My number 3 cylinder still doesn't seem to be firing. No change in plug color, and it appears wet with fuel when removed. Not sloppy wet, but just a sheen of fuel on it. it looks brand new, even after a few 500cc tanks of fuel through it, on a test stand. Cylinder temps are around 120F degrees on the #3 with 195F to 225F on the others. Turbulator on and vanes rotated through multiple positions has varied success in smooth idling(850rpm on 26x16 2 blade) and around 5100rpm when tuned for max with the same prop. When transitioning there is a definite miss and puffs of white smoke in the midrange, which clears up at full throttle. If I richen the high end, this clears up a bit, but then the prop is turning around 4800rpm and the #3 runs even colder. when removed from engine, the #3 spark plug shows good spark, so i think it's firing.
Some relevant facts:
1. Used engine - beilieved to be pre-november 2009
2. Some carbon buildup visible when looking through spark plug hole. Not sure of hours or gallons through it - Should I remove the heads and clean the piston top and valves or just continue with seafoam until it cleans itself?
3. 24x18x3 SEP 850-4000 rpm
4. 26x16x2 fiala 850-5100rpm
5. 93 Octane with 1 oz seafoam/gallon and 50:1 Amsoil Dominator(also ran a few tanks with 50:1 redline) I have a gallon of both oils, so I can use either.
6. CH ignitions electronic ignition installed
7. New rcexcel iridium Plugs all the way around gapped at .015"
8. Valves set at .07mm
9. Not a lot of difference when running with or without the turbulator. Maybe a bit smoother with it, but a negligible difference.

Could compression be an issue? I have noticed that after a few runs, all on a stand, that there is oil/unused fuel seeping past the valves on the #3. No carbon showing on outside, just oily "drips". I'm wondering if the valves have never fully seated? All others are clean and show no signed of seepage. Any guide to checking compression on a radial? 1 revolution or more? and what pressure should I be looking for on my gauge?

One idea I had, was to swap the head of one of the seated and firing cylinders with this #3 and see if the drip stops, and if the cylinder comes up to temp. Thought being that the #3 head valves could properly seat in on another cylinder and lead to all 5 coming up to spec.

Any guidance would be appreciated as I desperately want to fly this engine, but would like to have it running as best it can before putting in the air. It never offers to die on the stand, unless I idle too low, so I don't think its unreliable, it's just not firing on all cylinders.

Thanks,
Mike

Last edited by bigmikew; 08-08-2018 at 06:17 AM.
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Old 08-08-2018, 06:23 AM
  #4140  
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Tom and Greg. I claim to know absolutely nothing of the properties of 2 mix oil at combustible temps. I switched to Amsoil Dominator at the advice of Gotz. My Valach 210 requires this at 30/1 and I did not want to void the warranty when it was new. The Valach opposed twin depends on blow-by to lube the internal workings where the Moki cylinder is fed fuel internally.
I run Amsoil in my 2 Moki's at 45/1 as well as my DA. The benefit for me in using any oil in the Moki is mixing Seafoam at (2 oz / gal).
At either the beginning or end of the flying session, I inject about 1 ounce of seafoam into the fuel tank of 16 oz gas and run for a short time to clear out any carbon or gunk that may hinder the engine. What I notice every time is a better running engine at mid-range. The mid range missing goes completely away and the engine runs like a well tuned sewing machine.

Regards - J Tab
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Old 08-09-2018, 11:54 AM
  #4141  
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Mike,
Based on the RPMs you are registering with those propellers, it appears that all of the cylinders are making full power. I have never used a turbulator in my Moki and my two friends with high time Moki 250s have not either. All our engines (except mine now) run great. By great I mean they all pull their respective scale 32" or 30" three and four blade Solo propellers at 3500-3800 RPM on the ground (this is what we set our pitch for). I have never chased the #3 cylinder running cool issue. If the engine pulls like it should at cruise and full power, I don't care if there is a bit of chugging and popping at midrange and below. In fact, I love the chugging sound because it sounds awesome during a big Corsair or Thunderbolt flyby.

I think your engine is running fine Mike, follow your #2 option and quit driving yourself nuts chasing the #3 cylinder temperature issue. As Goetz has stated numerous times, "...do not unnecessarily disassemble a Moki radial..."
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Old 08-12-2018, 12:45 PM
  #4142  
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Saw some better results today after playing with the turbulator and also going to a higher voltage on the ignition battery. Now seeing #3 firing and the engine making about 300 more rpms.

Thanks Tom(Maxam) for the advice via telephone, and for all who offered input. So for me it looks like the turbulator tuning and a higher voltage ignition battery were the key, together with a tone of needle adjustments, now have me firing on all cylinders and blowing no oil from the #3 exhaust side.

One last question: how far are you guys backing off of max rpm settings on the ground? Should I tune for max and back off 100 rpms or just tune to max before it starts losing power?

Thanks again.

Mike
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Old 08-13-2018, 06:06 AM
  #4143  
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Originally Posted by bigmikew View Post
Saw some better results today after playing with the turbulator and also going to a higher voltage on the ignition battery. Now seeing #3 firing and the engine making about 300 more rpms.

Thanks Tom(Maxam) for the advice via telephone, and for all who offered input. So for me it looks like the turbulator tuning and a higher voltage ignition battery were the key, together with a tone of needle adjustments, now have me firing on all cylinders and blowing no oil from the #3 exhaust side.

One last question: how far are you guys backing off of max rpm settings on the ground? Should I tune for max and back off 100 rpms or just tune to max before it starts losing power?

Thanks again.

Mike
Mike are you using the black "top hat" looking ignition?
I tune for max rpm around 3800 on the ground, the rpms will go up from there in the air as the prop unloads. I will use throttle management when in the air especially on down runs to make sure it doesn't over rev.
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Old 08-13-2018, 06:32 AM
  #4144  
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Originally Posted by GeorgiaFlyer View Post
Mike are you using the black "top hat" looking ignition?
I tune for max rpm around 3800 on the ground, the rpms will go up from there in the air as the prop unloads. I will use throttle management when in the air especially on down runs to make sure it doesn't over rev.
I'm using the ch ignitions conversion for my engine. Its marked for 2 cell, but speaking with Adrian at CH led me to try the higher voltage battery. It seems to have helped.

What prop and engine are you tuning to 3800rpms? I've got 2 props, a Fiala 2 blade 26x16 and a 3 blade SEP 24x18. Both being used on the Moki 150.

Thanks,
Mike
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Old 08-14-2018, 06:20 AM
  #4145  
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Originally Posted by bigmikew View Post
I'm using the ch ignitions conversion for my engine. Its marked for 2 cell, but speaking with Adrian at CH led me to try the higher voltage battery. It seems to have helped.

What prop and engine are you tuning to 3800rpms? I've got 2 props, a Fiala 2 blade 26x16 and a 3 blade SEP 24x18. Both being used on the Moki 150.

Thanks,
Mike
Mine is a Moki 250 with 32" three blade solo prop variable pitch. I adjust pitch to get the ground 3800 rpm. I use to have a Moki 180 with fiala 2 blade 26/16 I believe a recall it being about 4000 or a little more on the ground with that prop. I would always use throttle management to not over rev when flying.
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Old 08-14-2018, 08:22 AM
  #4146  
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Guys, Slowly making progress on my 41% Pitts Model 12. I've had the short kit since 2006, and finally getting to the point of mounting all the hardware in the fuse before sheeting. The power for the Pitts is an older MOKI 215cc radial. I have a fuel pump from Dr. Vogelsang, but not sure how to properly hook it up, both from a plumbing standpoint and the electrical side. Can anyone share what all the hookups are for? Fuel-wise, there are three connections, one on top that is marked "R", which I take is the return line back to the tank. On the front face are two nipples, one is larger in diameter than the other. The smaller one has an engraved arrow pointing to it. I'm guessing the fuel from the tank goes to the larger nipple, and the smaller one (with arrow) goes to the engine carb nipple. How are my guesses so far? The other end of the pump has three Futaba-style servo connections (with the "key") and are marked RX, BAT, and IGN/PRG. I'm guessing the Bat is rather straight forward as switched power to pump. I'm guessing the "RX" plug is to control pump speed with a signal from the throttle channel? The "IGN/PRG" connection has me baffled completely. Any info on how to "hook-up" this pump will be appreciated. By the way, the name printed along the top of the motor says "PowerFuel RX"
The old MOKI 215 has the top hat style ignition box and was completely rebuild by Mike D. just before I bought it 10 years ago, and never run since.
One last question just popped into my head--Can anyone share a source for a set of needed feeler gauges that are small enough (width-wise) to fit the rocker arms of the MOKI. I have a couple sets, but they are all about 1/2" wide for automotive engine use, and would like to buy a set that will fit.

Thanks for the help,
Larry Fitch
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Old 08-14-2018, 10:01 AM
  #4147  
Maxam
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To all who are interested in the proper oil to use in the Moki's. I spoke with Julian and he has observed that a high percentage of repairs where RedLine was used showed galling and scuffing in the crankshaft / master rod area. He was willing to talk and carefully explain the issue. I looked back in my "oil history" and I was using Amsoil Interceptor. I have ordered the Dominator version. Even though my engines seem to be perfect I decided to make the switch.


Larry Fitch; The OS feeler gauges for their 4 strokes work quite well on the Moki valves. Also look back in the not too old history on this thread for the information you need on the fuel pump. -Tom
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Old 08-14-2018, 10:56 AM
  #4148  
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Originally Posted by Maxam View Post
To all who are interested in the proper oil to use in the Moki's. I spoke with Julian and he has observed that a high percentage of repairs where RedLine was used showed galling and scuffing in the crankshaft / master rod area. He was willing to talk and carefully explain the issue. I looked back in my "oil history" and I was using Amsoil Interceptor. I have ordered the Dominator version. Even though my engines seem to be perfect I decided to make the switch.

Larry Fitch; The OS feeler gauges for their 4 strokes work quite well on the Moki valves. Also look back in the not too old history on this thread for the information you need on the fuel pump. -Tom
I'm with Tom (and others) on the oil conundrum... I have used Red Line 40:1 in all my gassers, two and four stroke (with the Saito exception of 20:1), and have never had an obvious problem. Having just purchased a new Moki 180, I was advised (warned) by Goetz Vogelsang that EVERY Moki they have received back for internal damage was running Red Line. Apparently, Red Line is fantastic for two strokes, but not so much for four strokes where you must have a certain amount of un-burned oil making its way up to the valve train. Goetz recommended Amsoil Dominator and I immediately purchased 6 quarts to run in ALL my gassers. When talking about the life of a $4000+ engine, it simply isn't worth taking chances, especially when the guy who will warranty the engine makes his oil recommendation crystal clear. There are other factors, like prop, tuning, cooling/baffling, that can have an equally profound effect on engine life. Red Line has been a great oil, but I'm not taking any chances.
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Old 08-14-2018, 11:30 AM
  #4149  
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Tom, Thanks for the info. It looks like I did understand the plumbing set up for the pump.
Thanks,
Larry
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Old 08-21-2018, 11:27 AM
  #4150  
Captainbob
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Default Moki revelationa

I just finished a CompArf Corsair with a Moki 250 for power, and like many others on this forum have been stymied by the problems with this engine. I have now 11 flights on the aircraft and the engine is running great. Here's what i've learned about my engine.
I built a test rig in the begining and made the initial runs there. And like many others in this forum I found that it would quit, seemingly at "the drop-of-a-hat", would not idle reliably, overheated, and otherwise made me very nervous about using this engine in such an expensive bird.
During the first two test flights I found the engine would quit when I ran it up to WOT on the ground "here we go again". I flew anyway (against my better judgement) keeping the throttle well below full open. I wasn't any more at-ease, though, at the end of this flying session and decided not to fly the bird again until the engine problems were sorted out. At my wits-end and totally frustrated I recalled from the forum comments like: "never run the Moki 250 with the throttle butterfly wide open", "the carb is too big for the engine", "you have to make sure there is plenty of cool air for the carburetor", "the carb needle arm needs to be reset to a new height", "the needle spring needs to be shortened". And here's a good one, you have to have a "turbulator". etc, ad infinitum.
I have the choke on a two-position switch, and while thinking about the problem while tossing-and-turning, unable to get to sleep over this, it occurred to me: why not simply move the choke function from the switch to a rotary knob, that way i could use the choke as an ersatz mixture control. The next day I ran the engine up with this change and, "SHAZAM", I found that i could get a nice burbbley rich mixture anywhere I wanted, wide-open, mid-range, or idle with the choke knob at about 3/4 open.. I could adjust this knob and get the engine to quit rich or lean, "wonderful". Using this method, the engine does not quit any more. EVER. And i can turn off the pump while the engine is running and there's no change in RPM. No turbulator, no pump, no problem.
Conclusion: it seems that indeed, the carburetor is too big for the motor. The total pressure in the venturi is just not low enough to properly activate the metering side of the Walbro. By partially closing the choke you are lowering the total pressure inside the carb throat thus pulling in more fuel. That's why so many found the high needle so ineffective. It seems contrary to common sense to operate an engine with the choke not fully open, but as I said at the opening of my reply, I now have 11 flights on the corsair with plenty of power, a reliable idle, no overheating, and my confidence in the Moki 250 has greatly increased. I'm a happy camper.
Thhis winter I plan to experiment with a different carburetor, as in O.S. 8B. I'm sticking my neck out here, but with a properly sized carburetor the engine may not need a pump at all. Another set of problems eliminated.
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