Maxam

My Feedback: (62)

Brake cleaner is great. I do not like to get it on the spark plug wires so I face the engine down with the 10 mm shaft in a big socket from my tool chest. Now (outside) I can clean the engine around the valves etc and not get the cleaner around the back of the engine. Since it is sitting on the socket it is easy to turn around while cleaning but!!!!! don't let it fall over. -Tom

Der Goetz

My Feedback: (9)

Hello everyone

Götz here. As for the new ignition: you can run them up to 9V - that is where the main difference stems from. Yes supposedly the curve got changed a bit - but my one-man jury is still out on that one and I would love to learn from anyone who has indeed noticed a difference. The ignition itself- if you run it on the "old" 5.9 Volt - will/should not make much of a difference, it is not until you go up to 8-9V that it may or may not make a difference on a motor which shows suboptimal mixture distribution between the five cylinders. As I like to call it: it may or may not beat the rich cylinders into submission.
BUT: on a Moki that runs fine you will most likely not feel a difference. I would hate to see a fellow modeler spend all of this money on one of the new blue boxes in hope of finding those hidden extra 400rpm, for example.
If you fry your old ignition or if you feel that you are missing on the bottom cylinders every now and then (and all other and cheaper fixes have failed) - give the blue box a shot at 9Volt. Get yourself a Castle Creation BEC as well and set to 9V for optimal results.

reyn3545

Goetz has spoken... end of story!

Thanks for all of your help along the way, I think all of us have learned greatly from your experience, your time and your generosity.... but we still haven't touched the surface of your knowledge on these engines!

wphilb

My Feedback: (10)

I mentioned before that at the end of the last flying session we had a sticking exhaust valve on the number four cylinder of my Moki 150 so based on the recommendations here and from Gotz we pulled the plug and gave it a "Seafoam" spray treatment and added an oz per gallon of the liquid Seafoam to the fuel and also switched over to "Redline" high temperature 2 stroke motorcycle oil still at 50:1. Interestingly the number four cylinder plug had a cracked insulator. This either happened upon removal or was preexisting. The plug head was pretty fouled. I pulled number three to check mixture and surprisingly it was nearly perfect to my eye so we left it and the needles alone.


We then got six more flights on the Telemaster today in mid eighty degree temps with moderate to light winds. There was a noticeable reduction in cylinder head temps. Even after an eight minute flight and taxi time the highest cylinder head temp was 177, most in the 160s, number three must have cooled faster as the only recorded temp was 110. Prior sessions hand seen 210 degree plus temps. Air temp / humidity differences might explain a bit of this but not all. I got 4800 RPM max and a sweet sounding engine all day with the usual slight miss once or twice a pass. I'm convinced that number three cylinder is running. It sounds like a washing machine with rocks in it when number three dies out. Starts were scary easy, most on 1-3 flips with no choking after the initial prime on the first flight. There was an increase in black gunk from the exhaust but I was told to expect that initially.

So far I'm very pleased with the change in oil and the Sea Foam additive, will see how it fairs in a cowl! Many thanks for the advice and assistance.


Whit

wphilb

My Feedback: (10)

Don't know if this is of value but I'll continue to pass along. After the success we had with my second, slightly higher serial number Moki 150 on the Telemaster "flying test stand" we pulled it off and swapped in the first, very low serial number 150 that we have had overheating issues with on both planes we have tried to fly it on in the past (N28 and Meister F4u). We know all the components off of the engine itself are good and well tested so any issues are likely specific to the core of the engine itself. We ran it with the new 50:1 gas:redline oil mix with the Seafoam additive as well. First test run on the ground got a pretty quick lean/overheating indication so we richened the high end until we got about 4400 rpm on the laminated 28x14. The other engine yielded 4800 rpm but the goal was to test fly, not compare or try for performance.

Test flying today in low 80 degree temps with light winds we got 5, 8 min flights with no overheating or loss of power. We got a slight increase in performance and definitely improvement in sound, transition and ease of starting over the course of the morning. The engine started the day barely holding 4300-4400 rpm after taking awhile to clear its throat and finished with 4400-4500 that it was able to reach much faster. It did so while running at lower temps as each run went along. The last run we figured that it ran at about 180 to 190 degrees in the air, it was about that in shutdown after a 30 second taxi in. I was able to shoot multiple touch and goes and never had an issue with it accelerating after a long idle. It continues to take a bit to reach full rpm as it's still rich but for now I'm happy to leave the needles alone. The last flight I was more aggressive than I've ever been with a 150 and it ran acceptably the entire time. The low end especially is fine as it idles at 6-700 rpm and starts easily. There is still that occasional miss but not much worse than the second engine if not the same.

Questions I have. What am I seeing? Why is one identical engine with more run time running hotter but is now "improving" with a different oil? Is the Seafoam a factor? There sure is a lot of black still coming out of the exhaust but not excessive. Am I really seeing improvement or was it just too lean on the other plane? Is this a break-in issue? Neither engine has seen much more than two hours of run time and some engines take several gallons to fully seat rings etc. Today was probably 30% of the run time that engine has seen its entire life and definitely the most it's seen any one day (or year!)

Is this a prop issue? Previously this first engine only ran on 28 x 12 or 26 x 16 props and thus revved up to 5400 rpm, now on a 28 x 14 (and set rich) it seems much happier in the 4000 RPM range. It's worth noting that my friend Ken from Aus dislikes running his 150s beyond the 4000 RPM mark though Moki themselves say 5000 or 5200 is OK.

At at any rate, for those still awake, my plan is to continue to fly it in the large Telemaster and see if more run time either as clean out or as break in continues to yield higher RPMs and lower temperatures.

Cheers,

Whit

reyn3545

The key is that your motor is running better and you are happy with it. The stiffer prop may be keeping the motor in a better operating range, and the redline/seafoam will surely keep things running cleanly. Just go fly and enjoy!

Horsepoweraviation

My Feedback: (50)

Has any one run there moki with no exhaust?
Are there any test runs that you can hear what one sounds like?

nine o nine

My Feedback: (1)

I haven't myself but I heard one a few years ago I think it was at Rhinebeck. it didn't have the nice throaty sound that the collector gives and it wasn't loud. I love the cadence of a radial.....could listen to a Moki idling all day. Mitch

Hovis40

I tried my older 150 with no collector ring and as Mitch said, it was no louder and did not sound as good either. I also run this engine on Saber oil at 100:1.
Dave

skymaster68

My Feedback: (4)

Guys we are at the field trying to start a moki 250 for the first time, as this is our first time with this cane of engine we are just fliping as a comon 2 stroke engine with no results, any clues or ideas on how to start this engine will be welcome

IFLYBVM2

My Feedback: (360)

Sounds like it may not be wet yet. The fuel draw on this engine is notoriously weak without adding a pump, so lots of choking is required, especially for the first start of the day.
My procedure is to leave choke and ignition on, hand prop the blade threw 10-15 times, with a FIRM grasp on the blade, until you feel it 'bump'. Once you feel the bump, remove the choke and it will fire. My experience is that if you can't get a bump, it's probably not wet yet.
Other guys can chime in, but maybe this will get you on the right track.
-Mike O

skymaster68

My Feedback: (4)

Thanks we did that, spark plugs were wet..
we also tryed to see if we see a spark on the ignition cups with the spark removed from tje engine but didn't see the spark, could the ignition be damaged? Again, we have been doing what we do with a 2 stroke , remove the spark plug flip the prop and sparks can be seen, but in this case that does no happens...
any suggestion will help.
thanks
rgds from chile

reyn3545

If your plugs are wet, there's no reason to choke the motor. Be sure that the throttle is set around a "high idle" speed, and start flipping. If you know someone with an electric starter with a reduction gear on it, that may help for the first start. Seems like all motors, 2 or 4 stroke can be real bears to start for the first run.

Depending on how "wet" your plugs are, you may want to take them all out, blow them off, and cycle the motor rapidly to push any "extra" gas out of the cylinders.. let it sit for about 10 minutes, then put it back together... that should evaporate off any excess gas that could be preventing the plugs from firing.

wingstrut

Skymaster68, Like reyn3545 said, clean and dry the plugs, make sure the spark plug boots are carefully installed all the way down on the plugs and if you can see your ignition module, make sure the green light is on and cycling on and off as you rotate the prop.
The first time I started mine, I tried to start like I would a standard two cycle engine, after wearing out three fellow members arms I decided to start it the way Moki recommends.
Open throttle wide open, make sure the choke is fully closed, make sure you have at least two people holding the aircraft. turn on ignition and start flipping the prop.
Mine fired in about six flips, I brought the throttle to slightly above idle, opened the choke and it started the second flip and idled perfectly.
I don't really flip my prop I get two fingers on the prop near the hub and just push it through and it fires and runs great.
There is no need to flip it like a two stroke that four stroke will fire just turning it through slowly.
I hope you haven't changed the needle settings from the factory because I found mine to be critical, things will change greatly with just an eighth of a turn.
This is what I found with mine, not all may be the same.

reyn3545

If you're the least bit nervous about flipping a full throttle prop with the ignition on (I would be)... you can start with full throttle, choke on, ignition OFF and flip it about 6 times, then lower the throttle, take the choke off, turn the ignition ON and flip some more. The key is getting fuel into dry cylinders. the "pop": that you hear with the choke turned on doesn't really do anything but confirm that there is fuel in at least some of the cylinders.... so if you can get fuel into the cylinders without the "pop", it will start the same.

I realize with the ignition AND choke turned on, it shouldn't start running full speed at you... but the thought of the possibility scares me away!

wingstrut

Yes Reyn, I swore I would never start that monster at full throttle even with it choked, I figured those Austrians were sniffing a little weed.
Before I installed an electric fuel pump I was having a difficult time getting the engine primed, I decided cautiously to try the Moki instruction.
To my amazement the engine just turned about ten revolutions and shut down, then I continued with the normal technique.
Of course the pump is a miracle worker........I love it.
With the ignition off, works also, but you must open the throttle and choke the engine to prime.
For all you guys that this is your first radial, No matter how you start the engine make sure it is secured by at least two people one is not enough if the engine fires up unexpectedly.
On the bench make darn sure its a large bench, this engine creates a lot more thrust than you can imagine, be very cautious, you will only be careless with this engine once.
Let us know if you get it started.

reyn3545

Yep.. I'm a big fan of the pump too... but I've been through 2 bad ones to get the 3rd good one... a little disturbing. One just quit running, the other developed a leak. I decided to void the warranty and open up the leaking one to take a look... there's a 1/16 inch thick x 1/2 inch diameter round o-ring that fits into an oblong slot between the black and the silver parts... easy to see why they are prone to leaks. And if you don't get the pieces screwed back together absolutely perfectly, you'll compress the o-ring and the metal pump gears will bind on the housings.... very delicate motors.

Anyway, the third one seems to be working great, and like you, I wouldn't want to fly without it. I got the turbulator for the 250 also... I honestly don't know whether it helps anything or not, I never ran the motor without it... but it hits on all 5 cylinders at under 900 RPM. Its a keeper!

jairaksinen

Indeed, I measured about 80# of static thrust with Moki 250 and a Falcon 36X14 2-blade

wingstrut

I asked around about the turbulator for my 215 and it was explained to me that, If your engine runs fine don't use it.
Now that was a little vague, but my engine seems to run pretty good, the one cylinder is still running cooler than the other four, but it doesn't drop out and the engine runs great.
That is a lot disturbing about the fuel pump, a 35 dollar fuel pump that we have to pay 240.00 for that may not last.

I think the fuel pump helps a lot because of the constant flow of fuel and the ability to lean the engine a little bit more and not load up #4 cyl.

The 40 to 1 synthetic oil mix and the one ounce of sea foam to the gallon sure has made a difference also, actually without this thread and all the folks who have contributed to it, the Moki would not have lasted.

Greg Wright

My Feedback: (6)

I might be the first to have this issue.
But over the july fourth weekend (2014) i had one of the new Blue case ignitions go bad.
I'm waiting for a new replacement to show up to hopefully get the engine running again.
The engine only has about 25 flights on it since new at the beginning of this season.

So apparently after all the reading of the old ignition modules going bad. This new design really is no improvement except you can run higher unregulated voltage thru it.

My feeling is that they really need to make the cables a bit longer so that you can locate them further away from the vibrations of the motor.

samparfitt

My Feedback: (43)

Ditto on the cable length.

Greg Wright

My Feedback: (6)

One more question for all you Moki owners.

Has any one found a good quality name brand socket wrench that will fit the plug and also get in between the fins of the cylinder heads.

My plugs are so tight that the socket that came with the engine is getting twisted at the top where you put a screw driver thru the holes and i still can't get the plugs loose.

nine o nine

My Feedback: (1)

I've used my supplied socket for the 5 or 6 years I've owned a Moki. If it's possible you might try drilling new cross holes a bit lower than what you have. I've also found that using stout rod rather than a screwdriver works well and I give the rod a tap or two to break the thread open. Inertia seems to do the job rather than the force of just pulling or pushing evenly.
For anybody looking....I've always started a cold Moki using the full throttle/closed choke method. I always have a holder or two. It's of course VERY important that your choke closes fully. Because there's much more vacuum at low throttle/ closed choke there's much less chance of drawing too much fuel and flooding the engine. I'm not really sure that's why the factory instructions say to do it but it works great for me........but I did stay at a Holiday Inn. Mitch

wingstrut

Mitch, I love the Holiday Inn bit.
Make sure the engine is cold before trying to remove the spark plugs or you could bring the aluminum with it.

Maxam

My Feedback: (62)

Here are photos of my Bruce Tharp Super Flyin' King powered with a Moki 150. The engine I found new and a pre 2009 model so I could use a turbulator with it. There was a 100 degree temp spread between cylinders but careful positioning of the turbulator vanes brought the temp variance down to a 20 degree spread so now it is a great running engine. My 108 inch Yak with the 215 Moki is intense to fly but this plane is relaxing. The flaps on the mid position allow the plane to fly at a human running pace at below 1/4 throttle! Engine RPM is 2000 at this speed. What a blast! Notice the exhaust....pre-formed radiator or heater hose. Just slip on and go! I just built struts for the plane. I was a bit leery of the wing outer section joiner strength.