To all experienced MVVS 58 engine owners assistance required. I have just installed a hardly used 58 in my edge. nothing unusual about the installation that i can see. using 4.8v for the ignition and a 24/10 prop for set up. The long the short of it i cannot get the engine to run for more than a few seconds unless approximately 1/3 choke is continuously applied. This made me think it was running lean so i kept opening the jets. no help there. then i stripped the walbro carb right out, cleaned it and checked all the holes by spraying petrol through them. all seemed to be fine with the carb yet the engine did not perform any better. Also a point worth mentioning i could not get it to prime the fuel tubing without disconnecting, yet once it was through with the choke closed fuel would drip out of the carb. a couple of swings and it would pop nicely and start without too much difficulty after that, just not run. The top of the fuel tank is at the same level as the bottom of the carb but i thought these carbs could suck quite well. certainly no problem when i had the zenoah in there.
Any thoughts on this would be most appreciated, whether it is the carb, timing or anything else for that matter.

happy flying, for some anyway!!

justin

It seems you have not connected the crankcase pulse line to the cast carb cover nipple.
It draws fuel on the choke only now, but without pump action it will not run without choke.
If the ignition is the new ICU type, voltage is too low and you should use 2 LiPo or 6 NiMh.
The Vlach ignition needs 4.3-6 volts only.

Pe , you are the man, i have read your site back to back. i have the Vlach ignition. I did connect the crankcase line but i agree i think we are in that place, fuel not pumping. i did read on another page that if the reeds are not sitting properly then that prevents the proper blow down that very pipe. i guess the next thing to check.

regards
justin

yep it was the pipe. all happy now.[8D]

And we change to gas because nothing can go wrong.... go figure.
Good luck, many successfull flights, and sincere seasons greetings

[&o] sadly not the end of the road. i had assumed it was going to work because i had managed to get it to prime from the tank without problem yet--- it apperars when it tries to run, to be far too much fuel entering the carb even with both jets only 1/4 turn open. fuel drips heavilly out the back of the carb and as it says the L jet should be around 1 3/4 open. i am completely confused.

confusion!!!!! the carb as we know has two plates , one over the membrane held down with 4 screws and the other over the flapper valves and filter with the one large screw. i have identical spigets on both sides which has left me with confusion as to which one the cranckase breather line should be connected to. if i connect it to the filter side as in other warlbro carbs i have the engine will not prime or run without 1/3 choke applied. on the other side which expands the membrane which opens up the needle valve and so letting fuel in allows the engine to prime from the tank incredibly well yet far too much fuel is going through the system, completly wet too rich for the engine to be able to run. it is set up with the single large screw side facing up. any thoughts?

justin

Hi Pe.
firstly i would like to thank you for your help and your website is
very helpful to us all.
i still have some points of confusion which i have laid out on
rcuniverse under ( MVVS HELP ).firstly i need to know which inlet nipple the
crankcase air line should be attached to as there is one on top and
another on the bottom, or should both? is there such a thing as the carb
being upside down. according to a picture on your site the transparent
pipe should be connected to the top, the plate with the filter etc inside
as opposed to the diaphram. as you know like that i don't get any fuel
through without 1/3 choke and it does not prime. i also don't
understand how the diaphram will open the needle jet against the spring if
nothing is pushing it. unless a low pressure is built up inside to do the
same and this maybe is not happening? when i took the back of the engine
off the carbon fibre reeds both sat slightly open. i suppose this is
normal. i know there is a positive air ram in the pipe because i put a
longer pipe onto the nipple and put it into water. a bubble or two !
of air bubbled up every time.i am as confused as hell because i don't
think of myself as stupid when i go through mildly technical things
methodically but this one has got me. any thoughts would be most
appreciated.
regards
Justin

The cover with the single screw must be attached to the crankcase breather nipple. This is the pumping pulse line.
Leave the nipple on the 4-screw cover open at first. This is for connecting a line into the fuselage. In the manual are pictures how to connect the lines. A manual can be downloaded from my website.
Open both needles 1 + 3/4 turn and don't mess with them until you have the engine running
Fuel dripping from the carb means that your carb is not inclined towards the engine. Starting is better when the fuel enters the engine instead of dripping out. The engine backplate can be rotated in any position.
It is normal that the membrane petals are very slightly open. They must be sound, and not frayed.

thanks again for the help. i have read everything on your site to do with warlbro, mvvs and the forums. it obviously answered a few questions i had so sorry for that. i have stripped the carb down again, cleaned it, inspected everything and installed it as reading pages on assembly so i am positive it is all in correct order and all ruber components seemed in good condition. with the choke closed and stick forward the engine did prime which i hope is a good sign. if the choke is open it will not prime. i have not had a chance to run the engine yet as i live in appartments! cross fingers.

Justin........this may sound simplistic but how much fuel line are you useing to get from tank to engine? I have a Sig Morrisey Bravo running a US Engines 42cc with a
Walbro carb. The tank is not easy to get to so I used an extra long length of tygon the extra was wrapped in about three loops right next to the carb. As long as those loops remained full of fuel everything was ok, if not I could not get the engine to start without priming the carb several times. I removed all excess tubing and now it starts easily and runs great. Hope this helps.

Gene