MarkShapiro

My Feedback: (52)

Hello Jack. Yes, the pump tube should be plugged. I used a piece of 2-56 push rod wire. This is on strong recommendation from Gotz Vogelsang. I took his advise and my 250 runs very reliably. Good luck.

MarkShapiro

My Feedback: (52)

Does anyone have any feedback on the Bambula 32 x 18 laminated prop, marketed by TBM as specifically for the Moki 250?

FormerCA.

My Feedback: (8)

How about a Menz 32x14 for break in?

Scott Prossen

Jack, are you asking about the pump you can buy and add or the "pulse modulator" pump built on the Moki?
Sorry so slow.....currently traveling!

Scott

Jack Diaz

My Feedback: (1)

Scott, I am talking about the external pump (APS 380HV).
Wondering if the "pump primer line" (the connector on top of the pump) should be plugged if not used as per your suggestion.

MarkShapiro

My Feedback: (52)

Sorry for my last piece of advise, Jack. I assumed you were asking about the tube coming out of the festo fitting on the engine.

Jack Diaz

My Feedback: (1)

Thanks Mark, I see now what you meant.
I will plug the line from the carb as you advised.

I just wonder if the pump third nipple will suck air, or spit fuel, if left unplugged.

Instructions ask for that nipple to be connected back to the tank thru a dedicated tank connection. But also say that that is "optional".
I hate to make another tank connection if not mandatory. And Scott suggested not to use it.

Jack

Scott Prossen

Hey Jack
On mine, I just left the red protective cover on the nipple and have had no worries!

Again, sorry Im so slow right now.

Best to you my friend!

Scott

DENTO

Hope this don,t confuse thing more
REGARDS
JOHN

fredo

Hey guys.
I just received new Moki 150 and when I made attempt to bolt it to my plane, I noticed that two exhaust ring outlet tubes are offset to the actual engine. Now I'm a bit baffled. If I straighten the engine, the exhaust is off centre and vice versa.
How do you deal with this in your scale planes? I'm thinking, the engine is well visible from the cowling and it would look strange crooked, just to have the exhausts looking straight down.

Scott Prossen

Each model will present the engine different. I have done both. You will have to decide. If exhaust extensions are used then the engine can go straight up!
Good luck.
Scott

fredo

Thanks Scott, I was only going to use small teflon tube extentions that won't make much difference, so I guess the option is, installing engine crooked.

Scott Prossen

I have done that on two planes and never got any bad feedback from anyone. It really isn't too bad. Good luck with your project!

BIGDAMMODELS

Thanks Scott for your valuable info and knowledge today on the Moki 150...for someone I've never met or talked too, you made me feel right at home with our discussion on the phone today....Much much appreciation...your knowledge on these engines is top notch and I wanted to personally thank you here for the time spent with me.....I also talked with Vogelsang about the issues and both of you seem to hint in all the same areas pertaining to the Moki cyl # 3 high-speed misfire...what a great guy to converse with as well...very informative and helpful...great sense of humor...businesses need more of these type people in the wonderful hobby we share...this guy was working his butt off and helping me at the same time...lol....his words of wisdom and knowledge speaks volumes to our success with these engines....I've since talked with the owner, and we are planning a strategy as to what route to take here....I'll post my finding here when the engine is on the pipe and swinging the 3 blade wood in the recommended rpm range....here's a link to a video of her idling and showing no apparent problems at all...never a stumble...all cyl temps well within specs...700 steady...and will hold 600 as well...I even got 500 with out a cough...how can it be....http://youtu.be/nGNdpn52Nlo....again...Thanks to both of you for helping me sort through the issues at hand....I owe you both a good lunch....

germrb

My Feedback: (3)

Hey BDM,

See, there are some good guys left in this hobby. Now that you have obviously found the secret of smooth perfomance, how 'bout sharing some data.

Fuel pump?
Turbulator?
High Needle?
Low Needle?
Oil mixture?
Prop?
Altitude?

Sweet video,

BIGDAMMODELS

germrb
I have found all of my ballpark settings here...what a great and informative area to find the workings for the Moki...I've recorded some info from your post as well...as to your questions...no electric pump...no turbulator...high needle around 1 1/2...low needle...approx 1....give or take a bump...I'll get the exact turns next visit to the shop...my oil mixture is exactly 50:1 penzoil air-cooled 2 stroke...I choose this oil as it is used extensively in Rotax ultra-light engines and the test results offered by them ranked very high in the ultra-light oil market while back...full synthetics are great but offer little or no protection when the engines are setting idle in the hanger...a tad of mineral is mainly to protect internal parts from rust...condensation being a major failure of most 2 stroke fueled engines...more-so for the protection of the needle bearings and valve components...this oil also has a very high flash point so it protects well beyond most temps we experience in this hobby...especially if we bend the screws a little tight...or miss that magic in and out number for cooling air..I'm no oil expert but if it's good enough for Rotax to ensure it's customers of no in flight engine failures in ultralights...why not Moki I'm thinking...I use it in all my engines and have had great results throughout the years of modeling...even after setting sometimes for months....the prop is 24 x 18 from Vogelsang and I reside in SC right on the coast....pretty much sea level...the engine runs like a top at low throttle,mid range, but will drop #3 at random test running times when the throttle is applied towards wot...I've narrowed it down somewhat per the advise given today hopefully....this is one of the pre Nov 09 engines and VS highly recommends the pump and turbulator..my installation won't allow the Turbulator without extensive modifications to the firewall area...what I did find that makes a great difference in the running of the engine is to have the fuel tank as close as possible and slightly higher than the carb center-line...using the stock pump of course.....doing this has virtually eliminated prolonged hard cold start and allowed me to squeeze the needles a little farther in...response is instant at any given time...even cold...my valve lash is 6mm dead on..this is so very important and overlooked sometimes...1mm can change lots when the total is 6...it is vital that accuracy be established here... plug gap...15....we thinking that the pick-up or coil has a glitch thing going on and I'm going to pull the pick-up tomorrow and look for chaffing and what not...when the #3 cyl drops you can bring it back to 1/3 throttle or idle and it it heats right back up with the other 4 and runs great again on all 5...even if you don't pull the plug and clean it...valve train seems flawless...nothing stuck or dirty... I think it would idle for-ever if you needed it too, with no failure or stumble, without cyl failure or overheating...temps hover around 178f....even #3...we gonna use an inductive timing light tomorrow and see if the spark from the #3 coil vanishes with the cyl misfire...we confused a bit as it goes beyond our findings and research,but we are confident that it will please as soon as we find this little wot misfire bug....I'll post more accurate findings here when done and hopefully help another break the grasp of that rambling Moki ghost...

fredo

...my valve lash is 6mm dead on..this is so very important and overlooked sometimes...1mm can change lots when the total is 6...

I'm still new to this. Could you please clarify the above.

mick15

As previously stated elsewhere in this thread, the easy way to adjust valve clearances is as follows:-

Valve clearance is there to ensure the valve is actually closed when it should be, the clearance value is dependant upon cam design, in this case 6mm measured between where the rocker meets the valve stem.

To adjust this clearance the engine first has to be in the correct position, to achieve this rotate the propeller until the valves of #1 cylinder are “rocking� this is where one valve is opening the same amount the other is shutting, this can be felt by laying a finger across the rockers, you can feel when they are in the same position. Now rotate the propeller 360degrees, #1 piston is at TDC on the firing stroke. Loosen one locking nut and gently turn the screw down until it just nips the pushrod, back the screw off ¼ turn and lock the nut, obviously same procedure for the other valve. Now if you rotate the engine backwards 1/5 of a turn you will find the rockers “rocking� on the next cylinder to the left. Repeat clearance procedure for the reaming four.

HTH m

Scott Prossen

Hey Mick that's cool. I thought you were going to explain the "Turn the screw one flat" method but you came up with yet another and even better/quicker way of doing it.
Always love the imput from tthe boys abroad. Hope you are well and enjoying that very fine La7 of yours. She sure is sweet....love the paint job!

ATB my friend. Wish you were coming this weekend for MONSTER PLANES!

Scott

IFLYBVM2

My Feedback: (360)

Hi Guys-
Big Dam Models is my 'crew chief', so to speak, (and long time friend / flying buddy) and is working on my Byron T-28 with Moki 150 upgrade. As he mentioned above, our problem is #3 cylinder seems to rarely hit at all. After several gallons, the top of the #3 piston is still shiny, and all others are black, which tells me it is not hitting much at all. It will fire at idle, but as the throttle is increased, it cuts out. With the cylinder dropped, max rpm is around 4200. When it hits (rarely), we see 5100 or so. As BDM mentioned, a turbolator would require massive firewall reconstruction. Hard to believe that something else is not going on here. We did pull the hall sensor and it appears to have seen some rubbing; but would only #3 cylinder be affected by bad hall sensor ? Seems that way back on the thread there was a guy from Iowa that fought this same problem on one of the early 150's, like mine is. Suggestions please !!
Regards-Mike Oberst

jairaksinen

Probably you have tried this but I'll mention it anyway. On my Moki 250cc I had #1 cylinder firing occasionally. All the sparkplugs were new. However I took them all out and all of the plugs had different clearence for the spark. And the differences were quite big actually. So I took a new one with smaller clearance and it started working instantly.

BIGDAMMODELS

Here's a pic of the sensor...my inquiring mind would like a better or more accurate explanation of the spark timing if anyone knows...how many magnets are in the engine for triggering coils for instance?...the hall effect sensor or pick-up as we call it...is it 5 switches combined into 1?....the spark is for sure timed with the cams to fire in the proper order...is this where the magnets are located?...I seen a tear-down here and was curious as to the magnets locations and how many are in there...the system resembles most newer type ignition systems found today on modern distributorless engines in most all markets but lacks the complicated computer circuits and micro processors to meet EPA exhaust requirements and the multitude of sensors involved with them...my best guess would be that all of the battery voltage items in the entire Moki system are contained with-in the ignition module and on-off switches, therefore eliminating spikes and low voltages to effect the pick-ups and their function...makes for a very dependable system...the coils appear to be with-in the normal make of standard...my best guess would be that the pickup would be the weakest link in the system solely because it is subjected to high temps and rests in a bed of nasty grease...once it hits anything mechanical inside and the sealed coating is marred, I would assume that the grease would seep into it as it does the pulse pump, and render it useless or cause erratic misfire problems...anyone studied this system?...I bring my knowledge and questions here from years of diagnosing auto ignition problems and a Moki that's misfiring at wot...the Moki ignition systems do resemble somewhat but on a much smaller scale...anyone?.....

germrb

My Feedback: (3)

Hi BDM,

Thanks for all the great data. I do have one question. The gap on the CM6 plugs is nominaly about .018 from the factory. Where did the .015 gap come from? Three thousands can make a lot of difference on small plugs. Based on your performance I'm tempted to regap all my radials.

At the risk of insulting your expertise, my experience with poor top end performance has almost always been associated with ignition battery capacity. I don't have data on the max. current requirements as wot for Moki engines, but big twins can pull as much as 2 amps. If the ignition system requirement exceeds the batteries capacity, the engine starts missing badly. Just a thought.

Later,

mick15

There are four cams two inlet and two exhaust the cam ring runs at ¼ crank speed. There are for pick up magnets one for the idle timing and one for the high rpm timing. My guess is the idle timing would be in the order of 5degrees before tdc and the high end timing would be to the order of 30degrees before.

m



I cannot subscribe to the ignition battery theory, it only requires a minimal current to supply the coils, I’m sure you understand it’s the decay of this small current that produces the 20K spark.

Also bare in mind the cam ring being epicyclical the cam runs in the reverse direction to the crank.

m

BIGDAMMODELS

Troy built has .014 on their site if you search the 150 and look at the pdf manual they list for it...I felt that .014 was getting pretty slim and cool for my issues and settled at .015 at the moment...my experience with plug gap is inline with most peoples if they understand the difference's between min and max gap settings... we're trying to establish and achieve a suitable heat range to address a rich fuel problem during our diagnosis with #3...we should all know an increase in gap will produce hotter, so with this particular engine and set-up, we are trying to find a suitable "heat range" that will suit the #3 flood because of design and the other variables without changing what come standard oem with the engine....plug gap is an easy one to do first when a flood is apparent... things can be easily damaged as we know when playing around with things that are associated with the spark timing and leaner mixtures on engines...more-so air-cooled ones...we've played around with several "gaps" and found that the difference is there as far as engine run performance is concerned if changed....it varies so much between individual results though, that it becomes a personal touch for most...play around with it but do so in very small increments and sometimes it with make a huge difference in performance on an individual basis and correct small minute problems encountered on a personal basis or it can lead you in the direction to fix the actual problem many have here with 150's...factory settings are always a starting point on average but can and do change depending on that individuals set-up...fuel...oil...tank...altitude...etc...hence... .014 to .018 gap specs on the cm6 ngk...just be sure of your understanding in these changes and never do so for the sake of change only...Thanks for your input and never do I get offended weeding through issues with engine performance...it's how we fix things.......I also found that the system consists of a total of 10 cam ring magnets to make it function as designed...my guess would be 5 for idle and 5 for wot...engine rpm being the deciding factor for the ignition modules choice and the timing number used by it...Thanks mick15....very good info on them timing numbers...it makes good sense to see those numbers used...I'm gonna do a few more test tomorrow and try a few old school things to try and improve the 150's gurgling performance with #3, and try to help with the well documented problems between individuals running performances with the 150...I'll try to find some common ground that will help and apply to all that have them...I'm thinking that maybe some careful playing around with valve openings on the intake side of #3 may help tons if the ignition shows no apparent issues tomorrow....less fuel mixture in may help with better burn...and maybe it will not effect the others that are doing their job with complete fuel burn...I'll post as I play....we've played with 4.8 and 6.0 packs exceeding 3000mah and found no apparent fix to the problem, although the spark at the plugs seems bluer...if that's a word...lol...of course this is eye sight only...we'll look there again as we go...6.0 seems to be a better choice from a logical stand point...we'll see how she folds....Thanks all for the input...Bill