rbgetz

One cylinder not running. I have a new 300 and running for the first few times on a test stand. It has the new “blue” ignition box that I run a 2s lipo directly to. Before starting, the ignition box shows one green Led and one flashing green LED. When I start, both are green. When idling around 1000-1200, I noticed the temp on cylinder 4 was only 80 F when the other were around 115-125 F. When I increased the throttle a bit, the 4[SUP]th[/SUP] cylinder temp actually went down. I’m assuming that cylinder isn’t firing. I changed the spark plug on it, but no difference. Any advice would be greatly appreciated..

Maxam

My Feedback: (62)

RB, The cylinder temps for the running cylinders are very low!! Are you way too rich on the needle settings?? The temps should be around 180 to 220 but no higher. -Tom

rbgetz

Hi Tom... great point.. I might be rich on the mixture. It's literally only the first 3 times I've started the engine and haven't adjusted needles yet. . but outside of the mixture, shouldn't that 4th cylinder temp be close to the others? I'm assuming it's not firing or am I missing something?? Rob

Maxam

My Feedback: (62)

If 4 cylinders are rich and that one is reaalllyy rich it won't fire. Few Moki's are even on all cylinders perfectly. Those temps you mentioned are really low! There is a device called a turbulator invented by Detlef Kunkel in Germany. It is designed to even up the cylinders. Works well on the 215 and 250. I do not know if he is working on one for the 300. The cylinder showing 80 is not firing!!! That one is warmed some from the crankcase. -Tom

rbgetz

Thank Toms. you were right on... I pulled the plug on that cylinder and it was really wet. I leaned the low end a bit and it ran great with all 5 firing. It definitely seems to run rich while the fuel pump is on. I turned the fuel pump on while choking, Then turned it off and started the engine. once started, I then turn the pump back on. I thought the fuel pump would only push fuels on demand, but seemed like it was flooding in there. Could that of been just because it was so rich?

Maxam

My Feedback: (62)

Could be, The diaphragm in the carb should close the needle to the jets. If you are way too rich you will flood the carb/ engine when choking. If you have the fuel pump you will need to lean both needles! Don't run too lean! -Tom

rbgetz

I was running a straight 2s Lipo for the fuel pump while testing the engine. For those using a fuel pump, I was curious as to the voltage you're running the pump at? Obviously the higher voltage the higher flow. At 6V it states 375 ml/min and at 7.2 volts, 425 ml/min. I'd also assume part of my overly rich flooding problem was running a straight non-regulated 2S was probably way too high a fuel flow possibly blowing past the diaphragm??

GeorgiaFlyer

i run a 2cell lithium Ion battery un-regulated on my pump with no issues.

Maxam

My Feedback: (62)

I run mine on just 4 nmh's . Works great on both my engines. -Tom

joneswarren

This is an awesome thread for new Moki-ites. I am refurbishing a 3W Bearcat/Moki 250 with some crash damage and would appreciate advice on the following:

What is the most practical method of verifying that the 380 HV fuel pump is primed at the beginning of a flying session without removing the cowl? I have been advised to add a 2[SUP]nd[/SUP] Fuel Dot teed into the line between the pump and carb and to temporarily open it to verify flow/prime before starting. The Fuel Dot offered by 3W is best suited for this as it contains pressure. See the attached pump connection graphic from Vogelsang I have modified. However, this all seems like overkill and makes for a challenge in maintaining scale appearance. What are the experts doing to verify prime, which is critical for pump survivability?

One idea is to look for flow backwards out of the 1[SUP]st[/SUP] Fuel dot normally used for filling as it is connected to the return line from the fuel pump to the tank. This of course assumes the Fuel Pump is connected as shown the attached graphic (w/o the 2[SUP]nd[/SUP] Fuel Dot).

Maxam

My Feedback: (62)

Is your pump the same height as the bottom of your fuel tank and right next to it? If it is it will be primed during filling and have the help of gravity! -Tom

joneswarren

Thank you Tom.

Your reply sounds sensible. I have only bench run the engine with the fuel pump configured as you recommend and prime was easily achieved during tank filling. The 2nd Fuel Dot advice was from someone who burned up a Fuel Pump but I don't know how he configured it (need to ask). You know how RC pilots are; once they make an expensive mistake they make sure it never happens again.

Will anyone else confirm Tom's advice that verification of fuel pump prime is not necessary if the fuel pump is configured properly (at bottom of full tank and right next to it)?

Regards,

Warren

mick15

I recommend you set the pump to deliver no more than 4psi. I haven't used your type of pump so can't tell you how to achieve this.

rbgetz

I was told the same thing.. Also, if you use the optional return line on the fuel pump, number 2 on your diagram, that will prime the pump. In the pump manual it states: "This will allow for a constant loop which will assist in bleeding you system and keeping it air-free. This connection is optional and will render the manual bleed unnecessary. Or install a separate return to your tank". May be people opt not to use it which I'd assume then leaves more of a chance for the pump not to be primed

Warren, I just started a new 3W Bearcat a few weeks a go that I'm putting a 300 in it. May be we can start another thread. A winter project for me and would be interested in seeing what you have.. Rob

Jaketab

My Feedback: (2)

Regarding the fuel pump, I installed a 2nd fuel" T" on the line between the pump outlet and the carb - which makes a continuous loop and recirculates fuel back to the fuel tank. The 2nd "T" directs the line into the fuel filler line - which returns fuel to the tank. Have never had issues with priming.

Regards - J tab

joneswarren

Rob,

I sent you a PM.

I definitely would include the optional return line on the fuel pump for the reasons you cite. I talked again to the pilot who recommended the 2nd fuel dot and he confirmed he burnt his fuel pump up while using the configuration recommend by Vogelsang. He then added the 2nd fuel dot after replacing the pump. What scared him was that the issue was detected when the fuel pump started smoking and he thought the plane was going to catch fire. The one caveat about his pump setup is he located the pump on the fuel tank centerline instead of at the bottom or lower which may have prevented consistent pump priming during the tank fill process.

Regards,

Warren

Jaketab

My Feedback: (2)

Discovered an interesting source for Moki engines and parts from Heilemann Sternmotoren in Germany.
The below link and picture features carbon pushrods with chrome vanadium ball ends for Moki Radial Engines.

Regards - Jaketab

http://www.heilemann-sternmotoren.de...art&Itemid=200

rbgetz

Hi Jaketab, I just ordered a set for my new moki last week and they're on the way. Heilemann were easy to work and very good at communications. I've ordered from them in the past as well. I'd be curious from the experienced Moki users on their thoughts regarding the carbon push rods.

Hinckley Bill

My Feedback: (569)

Great site....thanks for posting

Eulboyington

Hi all Radials lovers °))

I'm specialised on model engines maintenance in France, and I made a alternative solution for OEM MOKI fuel pumps who failed several times in flights when completely saturated with black grease coming from the shµ^t front vacuum actuator.

I decided to shut up the MOKI vacuum actuator in front of the engine and fit a external WALBRO FPC-1 vacuum fuel pump ( less than 25 $). I used the same way as EVOLUTION engines to keep the air pressure/depressure by solder 1 brass tube 4mm diameter on cylinders 1 & 5 intake manifolds. Those 2 tubes are connected to a "Y" brass tube and then connected to the WALBRO fuel pump.
Important : The pop-off pressure of the WALBRO WT carburetor has been set to 1,00 Bar.
Less complicated and less expensive as a electric pump.

This very simple upgrade works now perfectly with success, I made a video on YouTube to show this work : https://www.youtube.com/watch?v=_t29AytY7NM

For more informations, don't hesitate to look on my professional Facebook webpage, search " Modelisme Micromoteurs Service "

Straightleg

Very interessting! What do you mean with pop-off preasure and how do you adjust that !?

/terje

Eulboyington

Hello Straightleg,

I'm very surprized that only few modellers in Europe take care of pop-off pressure on their WALBRO carburetors.......
You can access on all my technical videos about engines & carburetors maintenance and settings with writing my name "olivier ROGEAU" on YouTube ( If you write also my name on Google, you will be also very surprised °)))

Straightleg

Ok,very good, but only understand "oui" and "bonjour" in french !!

/terje

Eulboyington

There is a lot of videos in English who explain the "pop-off pressure setting on WALBRO carburetors", make a search with google !

Hinckley Bill

My Feedback: (569)

Great pages explaining both Walbro and Tilotsan carbs AND pop off pressure adjustment

http://www.aerocorsair.com/id27.htm

http://inventions.aerocorsair.com/id38.htm