Magnum .91 Four-Stroke Inverted?
02-09-2004, 07:34 AM
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Magnum .91 Four-Stroke Inverted?
I have a Magnum .91 FS that ran fine on a GP Big Stik 60. I now have it mounted inverted on a Ucando 60. It doesn't seem to run quite as well now. Is there some tuning tricks that I need to know to get this engine to run better inverted? Thanks.
02-09-2004, 09:15 AM
#3
RE: Magnum .91 Four-Stroke Inverted?
Get a hotter plug, the Thunderbolt four cycle is the hottest plug you can find. Make sure it is very well broken in, you may have to run it twice as long to get it to run inverted as right side up. Use fuel with no castor and low oil content. With all that some four strokes still need an on board glow ignitor.
03-03-2004, 07:20 PM
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RE: Magnum .91 Four-Stroke Inverted?
I have a magnum 91FS that is mounted inverted on a 45 degree angle in a 60 dragon lady. Runs like a watch. The comment about having the carb centered on the fuel tank is correct as well as having to adjust the idle mixture. If the carb is lower it will flood and run poorly. I can assure you from experience that they run fine inverted.
03-04-2004, 02:42 AM
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RE: Magnum .91 Four-Stroke Inverted?
Brownie:
Please ignore post #3, as his advice re castor oil is dangerous. Read this thread:
http://www.rcuniverse.com/forum/m_15...tm.htm#1585618
for a more informed discussion.
And your Magnum will run just as well inverted, with just as much power, as it did upright. When you have the tank properly located, and the carb adjusted correctly.
The carb adjustment is a little more picky when the engine is inverted, it has nothing to do with how much time the engine has on it or whether it's been run upright before. Keep at it, and you will lick it up. Not difficult.
See also this thread for more oninverted operation:
http://www.rcuniverse.com/forum/m_15...tm.htm#1585905
Enjoy.
Bill.
PS: Best in my experience for a 4s engine, upright, sideways, or inverted, is the OS "F" plug. wr.
Please ignore post #3, as his advice re castor oil is dangerous. Read this thread:
http://www.rcuniverse.com/forum/m_15...tm.htm#1585618
for a more informed discussion.
And your Magnum will run just as well inverted, with just as much power, as it did upright. When you have the tank properly located, and the carb adjusted correctly.
The carb adjustment is a little more picky when the engine is inverted, it has nothing to do with how much time the engine has on it or whether it's been run upright before. Keep at it, and you will lick it up. Not difficult.
See also this thread for more oninverted operation:
http://www.rcuniverse.com/forum/m_15...tm.htm#1585905
Enjoy.
Bill.
PS: Best in my experience for a 4s engine, upright, sideways, or inverted, is the OS "F" plug. wr.
03-27-2004, 07:38 PM
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RE: Magnum .91 Four-Stroke Inverted?
I have a UCD 46 w/Mag 91 FS, Had the same problem. Installed a Ironbay Reg., end of problem, no muss, no fuss or bother. Mount it in the cooling duct , plenty of room, two screws that line up between the fuel inlet and outlet, safty wire, good to go. Remember to remove the pressure line when re-fueling.
04-03-2004, 09:25 PM
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RE: Magnum .91 Four-Stroke Inverted?
Mark:
An Iron Bay (two words) regulator is one of two demand type regulators available for our toy planes. Usong the Iron Bay or Cline regulators allows you to put the fuel tank anywhere you want it, with the pressure feed tank location is no longer critical.
You can also use a pump, the Perry VP-30 is the one I like, and it gives you the same freedom of tank location without having to worry so much about leaks. And the Perry pumps cost less than the regulator systems.
Bill.
An Iron Bay (two words) regulator is one of two demand type regulators available for our toy planes. Usong the Iron Bay or Cline regulators allows you to put the fuel tank anywhere you want it, with the pressure feed tank location is no longer critical.
You can also use a pump, the Perry VP-30 is the one I like, and it gives you the same freedom of tank location without having to worry so much about leaks. And the Perry pumps cost less than the regulator systems.
Bill.
