Postby Phil Clark » September 29th, 2014, 9:51 pm
Yesterdays outing with the 335 at Longhorsley was 'almost' completely successful....apart from a troublesome rear Zenoah 45 which was refusing to do anything apart from idle. I suspect a blockage in the carb as needle setting are having little if any effect. Apart from that, everything went to plan. Front engine now running very well; we're on a 30:1 oil mix still running a little rich and we're already seeing 6,200rpm on an Engel 26" x 12" carbon prop, with a steady idle just below 2,000. Ground handling is good, as would be expected with such a wide track gear, but she does have a tendency to bounce a little on the nose strut when going over the odd bump at low speed. This disappears as speed builds.......the high thrust line pushing the wheel onto the deck. No other problems were encountered, so once the rear engine is sorted, we'll be back out for another session before final over 20kg sign off. Even with just the front engine running, acceleration is brisk.......no concerns she'd fly happily on the front engine alone.
......and the good news from today is that the troublesome 45 is now running like a swiss watch. The carb was initially removed, stripped and nothing found, so there was no option but to take the engine out and investigate further. All carb bend gaskets were correctly orientated so all diaphragm pressure port holes lined up. The Easy Start sensor was correctly wired but the flywheel/magneto gap was a little large, so this was closed up. The engine was then put on a test stand, fuelled, primed and was running with a dozen flicks. High & low needles were set at 1 1/4 on the High & 3/4 on the low and that was that......all is well, so I can only put yesterdays problems down to an excessive magneto gap, hence a weak spark preventing the engine from running at anything other than a rough idle.
Tomorrow will have everything re-installed and we'll try again.
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