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Engine basics => Engine set up tips => Topic started by: frank j. scire on March 21, 2011, 08:00:29 PM
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hey everybody,I've got a mccoy red head 19. mounted on a junior flite streak.I't ran fine on test stand.On the plane it burns up the prime then quits.I was told the fuel feed line where it leaves the tank needs to be paralel with the venturi.If this is so,can I move the feed line up {to a differn"t spot ] on the tank.There is not enough room to move the tank high enough on the fuselage.It"s a profile wedge tank that the kit called for.And space is tight.If moving the feed line won"t work.Any outher help would be greatly appreciated.
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hey everybody,I've got a mccoy red head 19. mounted on a junior flite streak.I't ran fine on test stand.On the plane it burns up the prime then quits.I was told the fuel feed line where it leaves the tank needs to be paralel with the venturi.If this is so,can I move the feed line up {to a differn"t spot ] on the tank.There is not enough room to move the tank high enough on the fuselage.It"s a profile wedge tank that the kit called for.And space is tight.If moving the feed line won"t work.Any outher help would be greatly appreciated.
I would be very surprised if the tank height was such that it wouldn't run. I would look for something that is restricting the fuel flow, like something in the spraybar. Take out the needle, and at least blast fuel through it with a fuel syringe. Even better, blow it out, then look through it to make sure it is clear. Also, fill the tank as normal, then try sucking the fuel through the feed line to make sure it is clear.
Brett
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I was told the fuel feed line where it leaves the tank needs to be paralel with the venturi.If this is so,can I move the feed line up {to a differn"t spot ] on the tank.There is not enough room to move the tank high enough on the fuselage.It"s a profile wedge tank that the kit called for.And space is tight.If moving the feed line won"t work.Any outher help would be greatly appreciated.
If the fuel feed pipe is indeed parallel to the venturi when you are trying to start the model (and I am taking this as 'the spray-bar is on the same horizontal plane as the pickup point of the tank' when the model is in its normal starting position) then the engine will flood when trying to start it. This is because one half of the tanks contents will run by gravity down to the spray-bar and could flood the engine into a stop.
You need to have the tank's contents fully below the spray-bar in a normal start position.
The run position in level flight must have the tank centralized about the engines central plane and sometimes adjusted higher to even out run speeds from upright to inverted.
But if you built it as per the plan I don't think that this really is the issue here - but you never know!
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What Chris commented can be a problem with a standard or open vented tank. It won't happen with a uniflow tank. I have had the same problem because I had soldered the end of the fuel pickup closed. Wasted a trip to the flying field, and now check to see that I don't have that problem before the tank leaves the shop.
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thanks for the tips.Got it started today,no adjustments outher than blowing out spraybar,and finding out how many turns on NV 3 1/4.Was the magic number.
Thanks again