MOKI RADIAL Care and Maintenence
03-23-2015, 04:51 AM
#3226
My Feedback: (62)
RBGETZ- Do not tighten the nuts after each run, You will over compress the seals. Mark them like I said with a sharpie. If they are not unscrewing...leave them alone!
RAGZ- Buy an infrared temp gun. Good ones around $80.00. The Moki 215/250 series need the turbulator the least and yet respond the most. My cylinders are all within 5-10 degrees of each other, before if I can remember around 30 or so degrees of each other. The engine will over all run cooler and smoother and not stutter at 1/2 throttle settings where the carb runs richer. Both my 215's responded identically to the turbulator. Your pump should have a diagram with it. On the front the larger nipple is from the clunk, smaller to the engine and the top swivel is tank return. Mount the pump right next to the tank and even with the bottom of the tank for best results.
RAGZ- Buy an infrared temp gun. Good ones around $80.00. The Moki 215/250 series need the turbulator the least and yet respond the most. My cylinders are all within 5-10 degrees of each other, before if I can remember around 30 or so degrees of each other. The engine will over all run cooler and smoother and not stutter at 1/2 throttle settings where the carb runs richer. Both my 215's responded identically to the turbulator. Your pump should have a diagram with it. On the front the larger nipple is from the clunk, smaller to the engine and the top swivel is tank return. Mount the pump right next to the tank and even with the bottom of the tank for best results.
03-23-2015, 05:20 AM
#3228
Thanks Maxam. However, should I go ahead and get the turbolator? What does that do to the carb? Move is rearward? This means I will have to rework the choke and throttle servo position on my carf p47.
Regarding the prop... are we supposed to dismantle all 4 blades before taking if off the engine? I don't quite follow this part.
Regarding the prop... are we supposed to dismantle all 4 blades before taking if off the engine? I don't quite follow this part.
03-23-2015, 06:54 AM
#3233
Great to hear Greg. I am on page 55 of this giant thread. Still don't see a solution to collect the black stuff coming out once a pump is installed...cant it just be collected in a small bottle via a tube? Rather than splashing around the entire engine and cowl.
03-23-2015, 06:56 AM
#3234
Is there a reason why there are no images in this post? Infact a few more posts before this also have missing images.
I hope the following helps in the understanding of the pulse pump grease issue. The first (1st) photo 091 is a front view of the MOKI 250 with the nose case removed. The view shows the gear assembly consisting of the ring gear (timing gear), the two planetary gears, and the center crankshaft drive gear. This gear is actually machined into the crankshaft itself. (See photo) The planetary gear at the bottom of the photo drives the pulse pump connecting rod by an off center concentric lobe.
The second (2nd) photo 1033 shows the pulse pump connecting rod and piston located in its installed position on this lobe.
Photo three (3) photo 092 is the underside of the nose case as removed. Note the amount of grease that has been slung by centrifugal force to the outer radius of the nose case. You can now see how this grease ends up in a position for the pulse pump to allow it to pass by its piston seal to the top side of the piston and out of the tube, and/or the air intake hole in the pump housing. See photo four (4) photo 012 which shows the pulse pump parts layout.
My explanation of why some Powerplants pump more grease than others is dependant on where the grease is slung during initial runs. The more grease distributed to the pulse pump location, the more likely you will pump more grease than an engine which had more of its grease slung to the opposite side of the nose case.
Concerns you may ask? I have only one (1). In the event the intake air hole, or pulse tube become clogged and the grease builds up inside of the pulse pump cylinder to the point of causing a hydraulic lock, (grease will not compress, so the lock occurs when the piston can not complete its upward travel due to the grease, thus causing a stopping of the piston travel in the pump cylinder), then something has to give. So what is the weakest link? The piston connecting rod, or the planetary gear lobe? Who knows, but I surmise either situation will most likely result in an excessive side load to the planetary gear, possibly damaging the gear pin and allowing this gear to bind into the crankshaft gear leading to a catastrophic engine failure.
Fixes you may ask? I suggest the removal of the pulse pump assembly and using the electric fuel pump for fuel distribution. However, the nose case must be removed to accomplish this step. I plan to remove mine during its rebuild I am currently conducting. If you choose not to remove the pump, keep an eye on the pump for clogging. If you have had grease passing in the past, and it stops be cautious. Also track how much grease you are losing. Like a slow drip of an oil leak, it only takes a short time to loose a lot of oil.
hope this info helps some.
The second (2nd) photo 1033 shows the pulse pump connecting rod and piston located in its installed position on this lobe.
Photo three (3) photo 092 is the underside of the nose case as removed. Note the amount of grease that has been slung by centrifugal force to the outer radius of the nose case. You can now see how this grease ends up in a position for the pulse pump to allow it to pass by its piston seal to the top side of the piston and out of the tube, and/or the air intake hole in the pump housing. See photo four (4) photo 012 which shows the pulse pump parts layout.
My explanation of why some Powerplants pump more grease than others is dependant on where the grease is slung during initial runs. The more grease distributed to the pulse pump location, the more likely you will pump more grease than an engine which had more of its grease slung to the opposite side of the nose case.
Concerns you may ask? I have only one (1). In the event the intake air hole, or pulse tube become clogged and the grease builds up inside of the pulse pump cylinder to the point of causing a hydraulic lock, (grease will not compress, so the lock occurs when the piston can not complete its upward travel due to the grease, thus causing a stopping of the piston travel in the pump cylinder), then something has to give. So what is the weakest link? The piston connecting rod, or the planetary gear lobe? Who knows, but I surmise either situation will most likely result in an excessive side load to the planetary gear, possibly damaging the gear pin and allowing this gear to bind into the crankshaft gear leading to a catastrophic engine failure.
Fixes you may ask? I suggest the removal of the pulse pump assembly and using the electric fuel pump for fuel distribution. However, the nose case must be removed to accomplish this step. I plan to remove mine during its rebuild I am currently conducting. If you choose not to remove the pump, keep an eye on the pump for clogging. If you have had grease passing in the past, and it stops be cautious. Also track how much grease you are losing. Like a slow drip of an oil leak, it only takes a short time to loose a lot of oil.
hope this info helps some.
03-23-2015, 01:13 PM
#3235
I usually bling out any pane with all i can stuff in it, lol .. I got the turbulator , filter, pump and high volt ignition for mine ... I am leaving the turbulator off as no one has needed on the 250. I just want to make sure i have reliable fuel supply, and the high volt ignition should be able to even light weak farts on fire 
... With a clean airframe thats well blown out, I dont have the filter in use either ..
Voy
... With a clean airframe thats well blown out, I dont have the filter in use either .. Voy
03-23-2015, 01:47 PM
#3236
My Feedback: (62)
Ragz, I just wipe the black grease off after each flight. Just takes a sec. The turbulator will move the carb back about two inches which in my case on both planes makes it easier to hook up the fuel line, choke and throttle. You can call it bling but when a $125.00 part makes a $4000.00 engine run much better I will do it. Listen on youtube to a bunch of moki's running at part throttle, some of the cylinders are miss-firing and running rough. I choose to have an engine run on all cylinders at all throttle settings smoothly. A small percentage of Moki's run very well without it. Run yours before buying one and see! I had one Moki run just fine with the supplied pulse pump, the other 4 did not and were inconsistent with fuel delivery. There is no exhaust residue on either of my planes and I run 44 to 1 gas to oil.
03-23-2015, 01:58 PM
#3237
Everyone running a 250 will tell you a turbulator on that engine is more trouble than its worth and there is no need for it ... the 150 and 215 are the ones that benefit from it . I also got this same info from Gotz Voegelsang directly .. This is the reason im not going to use it and consider it just bling .. but hey, as long as it runs right, that's all that matters 
Voy
Voy
03-23-2015, 02:24 PM
#3238
My Feedback: (62)
Not everyone. I communicate with the inventor of the turbulator in Germany. The 215 and 250 are identical engines other than the cylinder bore and matching piston. Anyway, Ragz, here is my feeble attempt at photographing my installation. I think if I recall, the Carf P47 has a "Moki Dome" which may make the turbulator installation quite difficult.
Another benefit is the carb is moved further away from the engine heat which adds to the consistent running. I wish you much success with your P47. It is my understanding that this Carf model flies very well and will glide in with decent altitude if the engine quits! .....eeeek!
Last edited by Maxam; 03-23-2015 at 02:27 PM.
03-23-2015, 03:08 PM
#3239
My Feedback: (62)
Voy, I am with you on the filter. It seemed to introduce some inconsistent running. The mount for it I do like. If you look at my pictures in the previous post you can see a rubber tube that has an upward bend attached to it. If I accidentally over choke there will be no gas dripping in the model. Plus the filter is really heavy! -Tom
03-24-2015, 01:10 AM
#3240
I run several Moki 250 without fuel pump or turbulator. They all work fine. The only thing you really need to pay attention to is that the fuel tank sits a little bit above the carburator, that's all.
03-24-2015, 05:06 AM
#3241
My Feedback: (62)
For all you Moki users with wooden props. I was taking the cowl off my Yak 55 SP which of course meant I needed to remove the prop. The plane sat all winter. I could not believe how loose the six bolts were. No they were not loose where you could turn them with your fingers but far too loose to run the engine. So I checked my other plane and yep, same way. We in Indiana did have a very cold winter and it was dry inside. I checked my other non Moki radials and some of them were loose too. Just a friendly reminder.....
03-24-2015, 07:22 AM
#3242
I have run the engine on the bench and it runs like a dream. I ran it with Motul at 50:1 and an SEP 32x18 2 blade prop. My bench runs were without a pump. It would start easily in 4-5 flicks and keep running like a clock. When I bought it from Hans at Airworld I requested him to get the bench running at their end and he was kind enough to sell the engine after a few runs. So, I am assuming the needles are all set for flight.
Now, once its installed, its going to be a different story. I will not fly without a pump. Not so sure about the Turbolator. Regarding the black stuff, I was just wondering if its a good idea to guide that stuff outside the cowl with a long tube.. perhaps it will add to the weathering of the aircraft Regarding the baffle, I plan to chop off the part that go between the cylinder and just keep the perimeter baffled...I hope thats a good idea. This will keep the ring cool as well.
Excited to run up the engine again on the airplane for the first time later this week.
A
Now, once its installed, its going to be a different story. I will not fly without a pump. Not so sure about the Turbolator. Regarding the black stuff, I was just wondering if its a good idea to guide that stuff outside the cowl with a long tube.. perhaps it will add to the weathering of the aircraft
Regarding the baffle, I plan to chop off the part that go between the cylinder and just keep the perimeter baffled...I hope thats a good idea. This will keep the ring cool as well. Excited to run up the engine again on the airplane for the first time later this week.
A
03-24-2015, 10:07 AM
#3243
My Feedback: (2)
Ragz,
Attached pic shows an inner cowl ring I made to keep the airflow from spreading over the cylinders in the large diameter cowl. If I find that temps climb too high, then I'll consider adding louvers and baffles to the cowl. Should have enough air exit at rear of cowl. I have the pump, but not the turbolator. Engine runs good. Just takes #3 cylinder a longer to come up to temp with the rest.
Good luck with your Moki.
Regards - J Tab
Attached pic shows an inner cowl ring I made to keep the airflow from spreading over the cylinders in the large diameter cowl. If I find that temps climb too high, then I'll consider adding louvers and baffles to the cowl. Should have enough air exit at rear of cowl. I have the pump, but not the turbolator. Engine runs good. Just takes #3 cylinder a longer to come up to temp with the rest.
Good luck with your Moki.
Regards - J Tab
03-24-2015, 11:17 AM
#3244
I have been reading this amazing thread since the last few days. I find a lot of pictures missing from the previous pages. One such bunch of pictures that I would love to see (now missing) should be on page 82, post #2042, posted by Warbirdracer. These should be images of the pulse generator and basically the front end of this amazing engine. Is there any place these images can be obtained from? Are people still recommending to remove the grease from the front and replacing with thick oil. I am still on page 82, so I don't know how the story unfolds
thanks
thanks
03-24-2015, 01:16 PM
#3245
My Feedback: (62)
Rags, I do fly my Moki's a lot and the grease issue is at the back of my mind. I did buy a can of grease as recommended by Gotz and I inject about 10 cc through a cam follower housing after about 50 flights. The oil instead of grease certainly makes sense. I would forget about it for awhile and just enjoy the engine. Your prop selection is spot on. That is weird the pictures are gone. The cylinders should be kept below 220 F temp wise.
03-24-2015, 05:44 PM
#3248
My Feedback: (62)
Whit, J. Tab and others, Here is a picture of the grease for the engine and how to inject. When injecting first turn the prop so the top forward cam follower and pushrod have the valve closed and depress the rocker so you can remove the pushrod. Now turn the prop so the follower raises up so you with tweezers can pull the follower out. They are quite long! Now as shown in the second picture inject the grease into the timing chest.
03-24-2015, 08:09 PM
#3249
Join Date: Jul 2011
Location: West Richland, WA
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I have an older 215 MOKI. I've owned it for about 4 years, and never had it out of the box. I bought the engine used from a friend here in the PNW that was getting out of RC and into building full size airplanes. I have read all 130 pages of this thread, and learned quite a bit. One thing I haven't seen discussed is how to get power into the ignition module. The "top hat" module is marked "+ & -", and it appears some type of connector should fit into the small opening with the two power leads. Can anyone share what type of connector is supposed to be used, and where I might buy a few?
Thanks,
Larry Fitch
Thanks,
Larry Fitch
