The Hirth engine has twin Mikuni Super BN 38 carburettors which are floatless, diaphram regualted with a return line to the tank as the they have their own diaphram pumps. The return line didn't go back to the tank but back to the filter, therfore I also thought it may be a vapor lock. So I spent the nights this week going out to the airpot and modifed the return line to now feed back to the tank. Because I have an electric pump I'm able to circulate the fuel and see any bulbs in my clear tube fuel gauge (that's where I returned the fuel to to). This morning I ran it up and tested with no luck, the rough running still exists (but at least the fuel plumbing is correct now :-). I've put a copy of the engine manual on my WEB page.
Next step is to have a tech look at the eclectrics tomorrow. Regards Barry Kruyssen Cairns, Australia RAA 19-3873 k...@bigpond.com http://users.tpg.com.au/barryk/KR2.htm ----- Original Message ----- Barry sounds like you could have a vapor locking problem or too rich hot problem. If mixtures are correct you could possibly be gapped too large making it hard to start hot due to lean mixture extra resistance. Colin & Bev Rainey
