LA7flier

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For those of you running a 3W 50 in your bird, I'm curious whether you are able to get a sufficient draw of fuel when the engine is choked by simply flipping the prop over or do you need to spin the engine up with a starter to get the adequate fuel draw? With the carb buried into the fuselage of the plane, squirting some fuel into the opening is not a possibility.

exeter_acres

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when choked, do you have the carb full open?

LA7flier

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yes...still doesn't draw enough fuel to get the engine going

rc bugman

My Feedback: (30)

Hi,

My guess is that the choke is not closing completely. If the choke is open a small crack, the carb will not draw fuel.

All 14 of my 3W-50s start with a choked flip (usually 3), then open the choke and flip about 3 times and the engine will start on fast idle.

Perhaps there is an issue with your reed valve not sealing completely. That would affect the fuel draw and easy starting.

Hope this helps

Elson

LA7flier

My Feedback: (1)

I thought of that but my engine came brand new with a quarter round cut out of the choke plate. Not sure why it comes this way since most choke plates I know of require full sealing to create a draw and a quarter round cutout doesn't allow for full sealing. Does your choke plate come as I've described? My engine is about 1.5 to 2 years old and I'm just getting around breaking it in

lowpass 202

I`ve had the same problem :
http://www.rcuniverse.com/forum/m_3570668/tm.htm
http://www.rcuniverse.com/forum/m_3716383/tm.htm

The first thing to check is the reeds.
I suspect that the pump diphragme on these engines sometimes loose flexibility and will not work on low speed. At least I found that the engine would choke a lot better when I rock the prop fast back and forth between compressions.
My engine was not run very often and you say yours has been sitting for two years? Sounds to me like the same thing, I`m no expert though..

LP

LA7flier

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Well crap. This is my third 3W engine and the first I have experienced this problem with. I guess I will have to check the reeds...thanks for the advice

DaddySam

My Feedback: (9)

LA7,
So we meet again, eh? I haven't fired my 3w-50 up yet, so I may find I have the same problem awaiting. It seems to me that by rocking the prop back and forth between compressions the carburetor should pump gas into the engine. It's not like a glow motor that needs to have the gas "sucked" from the tank by venturi action. Please keep us informed as to your progress. If I can peek into my carb I'll see if it has the "quarter round" cut out of the choke plate.
Sam

corsair01

Have the same problem with my 3W50. I need to flip it about 50 to 60 times to prime it. Then it takes another 10 to 15 flips (with the ignition on) before I get my first plop. Engine was send back to 3W. They changed the reedvalves but that didn't help much. Well, it did help a bit, before it was send back it didn't prime at all. I'm not very happy with the starting procedure, but once it runs, it runs like hell.

TManiaci

My Feedback: (6)

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!.