docgboy

Having a problem with idle. I have an older Moki 250 which I installed on a newly build Com-arf 250. Did some initial engine runs this weekend and the engine starts up well and the top end sounds great but the idle is inconsistent. If I lean the low end it runs at a good idle and then dies lean. If I richen it I cant get the engine to idle low enough and it won't shut off with the throttle.
I am not sure if this is a carb overhaul solution or I need to use a fuel pump. Any thought?

Maxam

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Is the idle stop screw removed or at least unscrewed enough so the throttle closes all the way. When the idle is too lean the engine will run slow but rough and will die when throttled up. When you richen the engine will jump to a high idle and run smooth. Richen still more and then the engine will be rough due to being too rich. When the engine does the high idle jump it is likely at the right mixture so the throttle position now needs to be lowered. If a person has a correctly tuned engine, upon starting a cold engine it will run rough at idle due to not being warmed up enough. After a minute or two it will "jump" to a smooth high idle when warmed up enough. This observation occurs with the throttle position at med to high idle setting on your radio. I do start my engines at mid to high idle. The fuel pump does make a more stable operating engine and I have one on all my Moki's. -Tom The carbs are easy to overhaul and there are guys that show how to do it on youtube.

Maxam

My Feedback: (62)

D-boy, another item to check for; on the older Moki's some of them have a small notch on the throttle butterfly cut out right by the idle jets. If so the engine cannot be stopped at low throttle. One of my 215's is an older one and has the cut out. I removed the butterfly and added a solder drop and filed to shape. Problem solved. The cut out is very small. I am not referring to the soldered over hole on the butterfly, they are all soldered over. -tom

docgboy

Max
I have removed the idle screw. I will unmount the engine and check the butterfly to see if it has the notch or is possibly loose.

Thanks for the advise
Scott

Maxam

My Feedback: (62)

Hey everyone, there is a new Moki engine available. No it is not a radial but rather a 160 twin. Check it out at Vogelsang. It is a weird looking engine!

LRFitch

Guys, I've just replaced the old cam followers (ball-on-the-bottom) in my old MOKI 215, and reassembled the pushrods, etc. Is there a simple way (or best way) to adjust the valves? Dr Vogelsang recommended I use the "flat bottomed" followers, and stated I'd likely need to adjust the valves several times as the new followers take a set against the cams. Any help with a good way to adjust the valves would be appreciated.

Larry Fitch

mick15

As previously written elsewhere in this thread,

Rotate crank until valves of #1 cylinder are open the same amount (known as rocking) rotate crank 360degrees, the engine is now at TDC firing stroke on #1.

back off locking nuts and down the screws until the push rod is just nipped, back off screw half a turn nip locking nuts.

For ease if you now rotate crank backwards 1/5 turn you should find valves of #2 cyl rocking, rotate crank 360degrees and so on.

m

LRFitch

mick15, Thanks for the response and information. I did see your earlier post (#20, I believe), but this version makes much more sense to me. Thanks for restating your technique--very helpful.
Larry Fitch

Blue_Duck

Hello all. I also have an older 215,now it's time to get it on a plane and start flying it. Maxam you had an earlier post about an old 215 with a brass idler on the cam ring. Sadly it was answered in private. Would you mind posting the info, it would really help me a lot.

Here is where I'm at--- talked with Vogelsang got replacement lifters (flat ones- removed the ball ones). Gonna use an electric fuel pump,will mix fuel at 50:1. Will tune for correct temps on #1 and #3. Want to put a teaspoon or so gear oil into the front case but not sure what to use synthetic or regular. Would really like to pull the front case and disconnect the gear driven pump, but not sure what I'm getting in to. Never could pull up the pics that Mick15 posted.
Gonna get a 37.5% Pilot Yak54 to break it in on.

GeorgiaFlyer

You are good with electric fuel pump and running 50:1 synthetic oil fuel/mix. I would not mess with trying to open the motor up and disconnect the gear driven air pump. All you need to do is remove the air tube from the pesto fitting at the back of the carburetor. As far as putting oil in the crank case, I think it is either gear oil or heavier grease. I believe the weight is listed in a previous post.

Maxam

My Feedback: (62)

Blue, I found out my engine had the good followers and steel gears. The brass one will still be good for a few years but you took care of the critical part. The balled lifters are bad news! Georgia is right. No need to mess with the pulse pump.

TonyBuilder

My Feedback: (11)

Hi Moki manias, I have a brand new Moki 180 in the box, never removed from the packing mounts.

Hit it me up if you want a good deal.




IB

Blue_Duck

Thanks Georgia and Maxam
My theory was to seal off the front case after mixing the oil in with the grease. I was also gonna check to see if the gear was indeed brass.

AC2

My Feedback: (34)

TB, sent you PM

Arthur89777mg

Hello everyone!
How can I make a new topic? I have a very interesting theme

TonyBuilder

My Feedback: (11)

I have four 12" round tip Solo prop blades. Brand new never been opened from the original packaging.
They were for the Moki 180. If you need blades hit me up with an offer.



TB

LRFitch

Guys,
I'm building a 41% Pitts Model 12, that will be powered by my older MOKI 215. Can anyone recommend a 3-bladed prop for this motor/airplane combination? I have a 32X12 wooden 2 blade that was recommended as the "breakin" prop, and will start with that. Nearly all full scale Model 12s have a three bladed propeller, so would like to go there. I don't intend to do competition flying, jsut simple Sunday flier stuff, and don't intend to run the engine much over 4000 rpm. Where does that drive the propeller size decision?

Thanks,
Larry Fitch

husafreak

My Feedback: (3)

I finally got to see and hear Moki's running at a big scale fly in on the old Castle Air Force Base here in CA, USA. Three different 250's. Wow! Nice engines. Got some good advice (fuel pump, ignition, props, etc.). I downloaded the dimensions from the Moki website for the 180 as this is the engine I would use in my FW-190. You Tube videos are one thing but in person these engines are a thrill to see and hear. It looks like there will be plenty of room under the cowl UNLESS the Moki dimensions do not include spark plug caps and wiring? They do not appear on the 3 view drawing.
Looks like I just missed a chance at a N.I.B. 180. I need to visit the forum more often

Maxam

My Feedback: (62)

Larry, The 32x12 is too low of pitch. The most common two blade size is a 32x18. I use a 34x16. Both load the engine to 4400 RPM. A three blade would be a 30x18, 32 x16. -Tom

Husa, the plugs do not exceed the engine diameter.

Jaketab

My Feedback: (2)

FYI - on the subject of props for the Moki 250, I just tried a Biela 32 x 22 on my 50 lb+ Delro Turner W4X. Ground rpm's hardly reached 4000. The plane flew very scale like and required a longer take-off. Air speed was reduced over the previous prop which was a Xoar Laminated 32 x 18. The only downside to the 32 x 22 was In the event of a bad landing approach, the engine/prop combination would not pull the plane out of trouble.
The Xoar 32 x 18 had very good performance, but would slightly over-rev. A 32 x 20 would have been a good compromise.

J Tab

LRFitch

Tom and Jake,
Thanks for the input and advice. Tom, The current prop was recommended by Mike Dooley at TBM a couple of years ago. To be fair, I think he recommended this low pitch to reduce engine load while the engine was first breaking in, not as a prop to use long-term--I think. That brings up a slightly different question. As I said, the engine is old, likely 15 years old, but I've owned it for about the last ten, and have never started it. The engine was "overhauled" by Mike and several new parts were swapped in. These included new pushrods, and a new cylinder and piston. So for those parts, they have never been run, unless the crew at TBM bench ran it a bit before returning to the owner (who I bought it from). How should such a new/old engine be treated at first fire-up? I intend to add an electric fuel pump, and run 50:1 synthetic oil/ gas mix, and of course, oil the external moving parts. Last question, for now, what should I set the valve lash to? I've read the how-to, but haven't seen the setting value.

Thanks guys,
Larry Fitch

husafreak

My Feedback: (3)

That is great news, the 180 should fit fine then.

FWIW at the Castle show a couple of the guys running 250's said they liked props pitched at 20 for flying. They didn't know what to put on a 180 but they wanted me to realize how high of a pitch they were running.

LRFitch

An additional question: Does anyone know of a source for a 30X18 or 32X16 three-bladed propeller? I've looked at several internet sites, and not found anything near those sizes.

Thanks,
Larry Fitch

Maxam

My Feedback: (62)

Go to Justmodelprops.com

GeorgiaFlyer

Solo props has them. They are adjustable pitch as well.