husafreak

My Feedback: (3)

Maybe the pump is not supplying enough fuel? Can you increase its output? Maybe just increase the voltage at the pump and see if the rpms Increase.

BobH

My Feedback: (2)

You might open the low speed needle a complete turn and try it.
Sounds like the engine is running lean on the low side when it transitions to high speed.

Ragz

The pump is running at 100%. I will pull out the plugs. Never removed them yet. Perhaps they need some cleaning or changing. Since the engine is quite new, I didnt think of changing the plugs yet.

CHECCO 67

Hello guys
Can anyone tell me how many kg of static thrust the moki 250cc 5-cylinder ??

Straightleg

Depends on the prop !

CHECCO 67

2-blade 32x18

Straightleg

Not measured, but from flying experience,I would say close to 20kg

mitchilito

My Feedback: (7)

Rags, it is unlikely spark plugs are causing your engine to run lean. You need to pull the fuel line off your carburetor run the pump and physically verify you have plenty of fuel. If you do I would suspect the Walbro carb. Get a carb kit and rebuild it. Even if it's new.

Jaketab

My Feedback: (2)

There are 2 - 5 mm bolts that hold the carb to the intake tube. Possible an air leak on the back side of the carb. Check the bolts for snugness. Maybe even remove the carb and use an anaerobic gasket sealer.

J Tab

Jaketab

My Feedback: (2)

Just recieved the APS Powerfuel 380RX - programmable. When all else fails - read the instructions. However no instuctrions included and can't find online.
Does anyone have instructions in English.

Thanks - J Tab

Jaketab

My Feedback: (2)

Just did a little research - hopefully this link will translate.

http://www.microsofttranslator.com/b..._RX%23Mounting

CH Ignitions

My Feedback: (11)

Here is the English manual for APS Powerfuel 380RX fuel pump

Thanks
Adrian

Jaketab

My Feedback: (2)

Thanks Adrian.
If I recall correctly - are you making electronic ignitions for the Moki 250 ????

J Tab

CH Ignitions

My Feedback: (11)

I make for the 150 and 180, I have a 215 and Julian is fixing it for me.
Once I get it back I will make for the 215, 250,400.

Is over a year since I try to do it ...and get sidetracked with other projects.


Adrian

mitchilito

My Feedback: (7)

I'm thinking of going a different route for fuel pressure to my Moki 300. We know that the walbro carb pump section works great without any help at all IF the pressure pulse pump is working properly. It has plenty of power to draw fuel from even far away from the carb.

Since I don't care for the stock pressure pump I'm thinking seriously about adding an electric air pulse pump to facilitate fuel draw. I see no reason to spend huge $$ on a pressure pump and run pressurize fuel lines when the walbro does a GREAT job of pumping fuel.

I have the benefit of a machine shop so I won't have a problem whipping something up. I could even run it on a speed controller and mix it to the throttle channel to vary pressure

I'd love to hear your comments.

Jaketab

My Feedback: (2)

As you already know, the biggest pitfall is the pulse tube becoming blocked with grease. The APS pump on my Moki has worked very well and allowed leaner needle settings. However, it's not the electric pump I object to, its the high price of that little pump after spending $4000+ on our engines. Go for it.

J Tab

mick15

You're describing a system I've been using for sixteen years, ever since the difficulties I had with an early 215.

I run a Flightworks 100 ( or a turbine pump, of which there are plenty about now) matched to a throttle mix which can give you a degree of inflight mixture control. The basic pressure is set by a 3mm loop into the 4mm fuel delivery line, the length of the 3mm line determines the base pressure. this pressure should be between 3 and 4psi. This system is relatively cheap and works reliably on all my Mokis.

m

mitchilito

My Feedback: (7)

Mick, I think you are pumping fuel with your flight works pump. Re-read my post: mine will be a AIR (pressure pulse) pump.

The advantages: no external fuel pressure outside the walbro carb, cheaper, simpler because it lets the carb work as stock.

Greg Wright

My Feedback: (6)

Mitch,

I have been using the APS electric fuel pumps on my moki's with great success. The difference that i have noticed between the Pulse pump on the motor and the APS fuel pump is that you are just getting a more consistent flow of fuel to the carb and your able to get better needle adjustment and throttle response. It's not pressurizing the fuel system in anyway as it has a fuel return line that delivers all of the unused fuel that the Walbro carb is unable to deliver to the engine. The carburetor is only able to use what ever amount of fuel it can pump to the motor and the rest is delivered back into the fuel tank.

mitchilito

My Feedback: (7)

I hear what you are saying, Greg. I have no doubt what so ever that the external fuel pumps work great. I just hate the idea of paying close to $300 for an external pump when there is a fine fuel pump, capable of supplying PLENTY of fuel, built right into the walbro carb. It just needs a reliable air pulse.

I will probably use a small brushless motor to drive a little diaphram pump using a brushless ESC mixed to the throttle channel so it pulses slow at idle and speeds up with throttle. It will have one simple air hose right to the walbro carb.

I'll keep you posted as I get it going.

IFLYBVM2

My Feedback: (360)

The electric fuel pump obviously works well, as indicated by the number of guys using them successfully. However, I have determined there are an almost equal number of guys who own multiple Moki's, do not own any external pumps, and run their engines box stock. The pump has it's advantages as Greg stated above, but also adds at least two more failure points in the chain, that being the pump itself, and the battery that drives it. And they DO fail-a friend of mine had his randomly quit just a few weeks back-luckliy, on the ground.
At the end of the day, everybody has to do what they feel comfortable with. For now, I am going to keep it simple, and run mine stock. Time will tell if I made the right decision. Just my two cents-
-Mike O.

mick15

Bear in mind Mitch the Moki has a pulse generator which delivers positive and negative pressures, necessary to gain the full travel of the carb diaphragm.

m

Maxam

My Feedback: (62)

And now the APS powerfuel is fancier! I got a new one that is controlled by the receiver so it can be either be mixed with the throttle so it runs slower at low throttle and faster at high. I will try to program it and the radio so the engine runs not so rich at mid/ low throttle settings. It can be run plain at a constant speed like the older ones too. It seems better made and quieter too. -Tom

mitchilito

My Feedback: (7)

After more thought about running an auxiliary pulse air pump I realized a problem with the logic. The stock diaphragm pump in the carb only receives pulses when the engine is rotating. An external pulse pump running all the time could very well generate excessive fuel pressure against the regulator. It's possible the regulator might be able to handle it but it is an unknown.

So let's change gears: grease clogging the stock pulse line is the real problem. I hate the idea of that grease being in there in the first place. How about I clean all the grease out of my front case and switch to gear oil (like I think it was Mick did). I don't think residual gear oil in the pulse line would be a show stopper like that crappy grease is. Maybe install an oil catch bulb (stiff wall) at the pump outlet? Hmmmmmmm

Greg Wright

My Feedback: (6)

Mitch,

When i was running the moki's straight out of the box. I noticed a very small amount of grease that would come out of the pulse pump. I also noticed that it never did get into the tube but rather it was coming out from the side where there is a very small hole that is acting as a breather port for the pulse pump. I would just wipe that grease away at the end of the day and it was good to go for the next time out. I would also check to see if any had gotten into the tube itself. I never had any issues with that happening.

So all i'm saying is, i have run them both ways with great success.