---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Sat 09/09/06: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:55 PM - 447 Problem (frank & margie) 2. 05:30 PM - 582 RPM Variation (Guy Buchanan) ________________________________ Message 1 _____________________________________ Time: 12:55:44 PM PST US From: "frank & margie" Subject: RotaxEngines-List: 447 Problem Ref the following: Subject: RotaxEngines-List: Re: Rotax 447 --> RotaxEngines-List message posted by: John Esch >Have you replaced your impulse line to the fuel pump ? Dave I replaced the pulse line with a new and one bought from CPS about 11 hours ago. It appears to be holding up. I pulled the exhaust manifold off last night didn't find any carbon on the piston rings only the normal buildup on top of the pistons and exhaust. Nothing excessive. The piston skirts are nice and shiney. >From what I can see there is no buildup of carbon on the other ports. I will see if I can borrow a bore scope to get a better look at the heads. My new pump, air and fuel filter should be here in a day or two. I have a feeling it might be the fuel delivery system that might have been the cause. The only thing is why it affected only one cylinder? Maybe I caught it pretty quickly and EGT never caught up on the #1 cylinder. Who knows, things happened pretty fast and I wasn't interested in watching the instruments at the time, just to get myself back on the ground before things really went south. John --------------------------------------------- John, You probably have a crank seal going out. Ten year old 2-strokes need to have crank seals replaced, and the bearings inspected by someone who knows what to look for. Check www.greenskyadventures.com for a discussion on this. I've been very impressed with the quality of their work. I ran a dual port Mikuni with one port blocked off, on a single carb Rotax, for 10+ years, with no problems. I've heard of others using a "Y" to connect to a single carb. The dual port pump is a good idea for U/L's that have a large vertical lift from the tank to the carb---Hurricane, Flightstar, etc. Another good idea is rebuilding the pump every 100 hrs or 3 years max. Use only the factory kit, the copies aren't as good. Fuel pump failures are too common. I'm probably going to add a Facet electronic pump to my Flightstar, in series with the Mikuni. Check the archives on The Kolb List for info on this. In addition to the obvious things like correct engine temps, good fuel and pulse lines, good fuel and oil-----there are three things I think bear watching on a 2 stroke. Fuel pump diaphragms per my earlier comment, crank seals, and bearing condition. Crank seals fail just from age as well as use. Bearings are made from a type of steel that will rust easily, if not kept in an oil film. Engines that don't get run frequently have a much greater chance of rusting due to the oil film drying out. I try not to let mine go more than a few weeks without being run, and Rotax says use preservative oil if more than ONE week until it's run again. Pennzoil makes a spray "fogging oil" that's easy to use for bearing protection. I think Lockwood has the fogging oil and the Mikuni pump kits. The back section of the CPS catalog has a lot of good tecnical info on 2 strokes. Another thing we've found is NOT oiling the air filters per the mfgr's instructions. Clean with solvent, and let the backflow from the engine take care of oiling the filter. Frank Clyma Jacksonville FL ________________________________ Message 2 _____________________________________ Time: 05:30:04 PM PST US From: Guy Buchanan Subject: RotaxEngines-List: 582 RPM Variation --> RotaxEngines-List message posted by: Guy Buchanan I've got a 582 that likes to wander +/- 100-200 RPM when cruising at 5800. (Actually, pretty much anytime.) It appears to be more than just prop loading, as I have to chase it with the throttle, and not just the elevator. Any ideas? Thanks, Guy Buchanan K-IV 1200 / 582-C / Warp / 100% done, thanks mostly to Bob Ducar.