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Ed,
My bird had a lot of trouble starting hot. I would run the Dukes pump for extended periods without picking up a prime. There was just too much vapor and the Dukes being a centrifical pump will not pump vapor. To add to the problems the engine driven pump was not in good shape either,
After the engine driven punp was replaced the engine ran better but the Dukes still had problems picking up a prime for both hot and cold start. Finally one day the engine just started running like crap. Fuel pressure was OK but no combination of thing got it to run any better. In fact when the boost pump was on it ran worse. I pulled the injector lines to check flows and found air in the fuel. More when the Dukes was running. It looked like the seals were bad and I was going to have to replace it.
In my case at first I could not find anyone who would rebuild it. It looked like Lancair had a special made and nobody could match up the number. Finally I found a rebuild shop but it was a 4 to 6 week turn around. I let them proceed and ordered one from Lancair. After getting the two speed Dukes by mistake. Which by the way should work but just be a little more expensive. I got the single speed model. It had different inlet and oulet connections but different fittings fixed that. It is a good thing I bought one from Lancair because it took Dukes 4 months to get the parts to the rebuilder.
With two new fuel pumps the plane ran great. However, because the experence with the Dukes and not being able to run it dry (vapor) I changed my start proceedure.
If the engine is cold I will try the boost pump first. If I can't build pressure in 5 sec it gets turned off. I crank the engine until I see the fuel pressure start to come up and stop. I then retry the boost which now is primed and will build pressure. If that does not work I try the engine crank one more time. If still no success I go to the hot start.
Hot start is just everything foward and boost pump off and crank until it fires. The engine driven pump will pump out the vapor until the liguid gets to the pump and will build pressure. With pressure the engine will run.
Check with Lancair if you can use the 2 spped pump if that is in stock. I have my rebuilt one on the shelf in the hanger as a backup. Maybe we can swap mine for the return of the rebuilt.
In any case good luck.
Ray
In a message dated 9/8/04 10:00:32 PM Central Daylight Time, edechazal@comcast.net writes:
My Dukes fuel pump (for IO-360) is up for replacement/overhaul. It "loses prime" most of the time, meaning it won't pump fuel to prime the engine, but will seem to generate pressure after the engine is running or after jostling from engaging the starter (sometimes it doesn't pressurize even then). It seems like it was acting up from day one.
What have you guys found is the best way to deal with this? The overhaul shops want a lot to overhaul the thing and if you don't send in the core, they charge more than if you buy a new one (?!). Crazy market here. Lancair's pumps are on back order for 7 or 8 weeks. Should I switch to the brand Aircraft Spruce carries (Weldon or some such)? Get it overhauled? There's nothing wrong with the motor, just the vanes I imagine.
Thanks,
Ed de Chazal
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