Fuel plumbing in a 1/3 Spacewalker

[RichardVaughanDavies]

Slowly but surely, my Spacewalker is nearing completion, but I have hit a snag. I can't get the motor to run, and this is because no fuel is reaching it. I have fitted the Du-Bro fuel filler just in front of the windscreen as per full size but feel this may be the problem. There is about 90mm vertical distance between fuel tank and fuel dot before it then descends to the carb.
Rough diagram attached.

plumbing.pdf

(48.54 KiB) Downloaded 71 times

I have stripped the carb to make sure all the holes line up, and they do. I would like to keep the fuel filler on the top if at all possible.

Question is, am I asking too much of the pump on the Zenoah 38 to draw the fuel that distance?

Your thoughts would be appreciated.

[Bob Thompson1894]

The fuel dot may be leaking. They are noted for it.

[Dave Collis 2296]

When was the G38 last run?
It may require a carb kit...metering diaphgram no longer supple, inlet needle stuck closed, pump flapper valves stuck or curled up not seating, etc. or as mentioned air leak in the fuel lines.
The walbro carb will pull fuel vertically quite a distance.

Cheers,
Dave.

[paul hughes]

I agree with Bob, The Dubro unit allows air to be sucked in instead of fuel. get rid of it.

[RichardVaughanDavies]

@ Dave. It has been about 18 months since I ran the engine in a test rig, so maybe a carb kit would be prudent.
@ Bob and Paul. If not the DuBro filler, is there another filler I could use?

As suggested by Steve Holland, I spun the engine over with a starter and the plug out and choke on. Took a few goes, but after exercising the filler (connect, dis-connect) and clipping the cover on tight, managed to get fuel to the carb. Fitting the wing mid-section and wheels back on, tried it in the back garden, and after a few flicks, it fired! choke off, and a few more flicks, it ran :-)

Only revved it for a couple of minutes, it is after all, fairly late for noisy engines, but enough to know that the engine is ok.

Thanks for your help.

[Bob Thompson1894]

https://hobbyking.com/en_us/alloy-fuel- ... tore=en_us with a 'T' connector. There are many similar.

[RichardVaughanDavies]

Looks nice and sparkly, HK order coming I feel :-)

[Bob Thompson1894]

There are others, that was the first cheap one on google. The Dubro ones are a problem waiting to happen. I think I have two still in packets in a drawer somewhere from the late nineties! Caused more dead sticks until we sussed out what it was...

[Robin Woodhead]

Richard,
I had a load of the DuBro units, as Bob mentions they are prone to problems, gave away at least 6. One of the things you should be aware of they come either for Gas or Glow, if you get it wrong the internal seals dissolve.

Get rid of them its not worth the trouble.

Robin

[Peter Siggins]

Hello Richard in the past I have fitted the Dubro fillers ,both petrol and glo,they both weren't perfect so did away with them.
I'm a great believer in the KISS principle and now with all my petrols using Dubro tanks I fit three tubes and leave the filler and breather hanging below the rear of the cowl
I have a 1/3rd Spacewalker with exactly that system and believe me you don't see the tubing below the rear of that big cowl,it makes life easy for plugging the tubes for transport as well.
Hope you sort it

Pete

[RichardVaughanDavies]

Went along the new,simpler, system of a t-piece and fuel dot. Again a few turns to get the fuel up, but started like a dream and ran faultlessly. Adjusted the throttle curve on the tx. and now have a perfectly acceptable set-up.

Thanks guys.