I just can't get my 3W50 primed. Even after 70 or 80 flips there's still no fuel in the carb. To get my engine started (only for the first flight of the day) I have to remove my spinner, prop and cowl. Than I eject some fuel direct into the carb. After that the engine starts good. After it has run for a few moments I stop the engine to install cowl, prop and spinner. (A lot of work eachtime). For the rest of the day the engine can be started. Does anybody has any idea what I'm doing wrong. To prime the engine I close the choke, throttle all the way open and flip the prop. Please let me know how you prime your engine.

That is what priming bulbs in garden appliances are for.

Lacking one of those,and since your engine runs well all day, you can assist the flow to the (dry) carb using pressure on the tank, like blow hard on the tank vent while flipping the prop in choke mode.

Hi,

Are you sure that your choke plate is closing completely? If the choke is not closing completely, the carb does not prime well.

Elson

Yep, it's closed completely.
I always empty my tank at the end of the day. Someone told me that the problem me be found because of that. Now I have refilled my tank so that the clunck stays wet. I'll see if it helps this weekend.

There you have it, leave the fuel in it, if it gets an air pocket in the fuel line, it takes awhile to get fuel to the carb. You just can't keep the airplane in the house!!!!

Tom

It does sound wierd but I have two ideas for you. First put a fuel "T" with a vent line very close to the carb inlet and flush air out of the fuel line right up to the carb when you start the day. Or, if it really, really needs to be primed (hard to believe) mount a small brass inlet tube facing the carb entrance and squirt fuel down it to prime the carb. No removing the cowl either way

All of those ideas are valid. My motor did the same thing. You will need to replace the reed valve. Remove the carb and base plate from the motor. Inspect the reed valve. You will find the reeds damaged. The valve is about $20 from Aircraft International. Make sure and seal the base plate down with some very light sealant during assembly. Your problem will go away. John

I'm sorry, but I don't know what you mean with "reed valve". English isn't our basic language and some words I don't know or understand. Please explane me what you mean with it.

Corsair, take off your carburetter ....look down the hole towards engine...you will see some plates made of yellow/green fibreglass..that is reed valve petals
hope this helps

I have mine on bench so here is a picture....

p.s. to check them take of the intake block and make sore the reeds are sitting flat and spring back if lifted (carefully), or blow and suck through the hole where the carb mounts, you should be able to blow, but not suck

Thanks Crusty, now I know what you mean. This valve is recently changed by the manufacturer so I don't thing this is may cause the problem. This weekend I'll know if not emptying the fueltank will help. Thanks for your replies, I will keep you informed.

Yesterday I tried to fire her up with the tank left full. This didn't solve the problem so I opened the engine to check the reed valve. The valve isn't closed at all so maybe the problem has to be in there. I tried to bent the valves so they are fully closed. I don't know if they will stay closed. Crusty, if you think this will cause my problems I'll buy a new valve.

Are you sure the carb plate is closing and SEATING all the way? Reason I say this is because I had the exact same problem with my DA 50..I called them and they said to loosen the screw on the butterfly and wiggle the plate around until its seated tightly..after I did this my engine primes on 3-5 flips instead of 30..It looked like the plate was closed but it was off by a few degrees.

Can you turn the reed valves over?
They may seal better with the curve going the other way.

I tried to turn it over, Diablo, but the screwholes aren't exact in the middle, so this didn't work. But thanks for the idea.
I'm sorry Jeremaih but I don't fully understand what you mean with butterfly. Is that the yellow thing you can see standing open in my pictures ? I so that are the ones I tried to bent by hand.

No..I mean the actual metal plate that opens and closes when you choke the engine..

Thanks Jeremiah, but it closes fully. That's not the problem.

Those reeds are knackered...technical term

replace reed valves. mine did the same thing i also changed to a three line tank and this seemed to help.imo

take a monokote iron and remove the peddles and iron them down flat and this will fix them right up.i do it all the time and it works great

For those still checking this thread:

I had all the same troubles you describe here. I just replaced a broken Reed Valve Cage and put in new Reeds. When I was putting it back together, I noticed there is no gasket between the motor and the phenolic block that the carb mounts on. There is a passage thru that interface that I believe puts the vacuum pulse on the fuel pump diaphram.

Well, I looked at it closely, and it sure doesn't look like it seals very well. Not only might you be loosing some of the vacuum to the pump, but you may also be pulling a leak into the intake. I sealed mine with a very thin painting of Pematex Silicone Gasket Sealer for good measure.

I'll tell you this... After all the troubles I have had flipping my ***** off trying to start this thing, and having to constantly resort to priming, my troubles are gone! I put it all back together, flipped it 10-12 times (it was all totally dry after disassembly) to get fuel pulled up, turned on the ignition, varroom! Choke off, second flip it started.

After that, I started it 14-15 times adjusting the needles. Started every time within two flips without choking. I am now convinced that I was either leaking air into the intake at the block, or not making enough vacuum to the pump, or probably both. It is sweet now. Cold starts, 2-3 flips with the choke on, blappppp... choke off, starts withing 2 flips every time!.