Losi mach .26

Old 01-22-2012, 04:41 PM
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Default Losi mach .26

The untunable engine? I think it just might be! I have had the worst luck tuning this engine I cant get it to do right for nothing. Anyone else had a problem with this engine?
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Old 01-22-2012, 06:14 PM
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Here is a question I know someone on here can answer. In the Losi manual the base start up settings from the factory on the high speed needle is three turns out from bottom and also three turns out from bottom on the low speed needle. I know I should know this, but I am just wanting to double check. When they say three turns out from bottom are they meaning 3-360 degree turns out or 3-180 degree turns out?
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Old 01-22-2012, 09:55 PM
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The Mach .26 should actually be very easy to tune, unless you have an air leak or something.

I would unscrew the LSN and HSN all the way out so they are flush. Then maybe one full - 360 degree - turn in on both.

If adjusting the needles doesn't help, you might want to try a new plug. Try an OS #8 or Odonnell purple.

If adjusting the needles and a new plug don't help, check your clutch. If the cluth is toast it won't stay running. Also check your fuel lines, that there is no crack in the tank, etc..
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Old 01-23-2012, 06:13 AM
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Originally Posted by Herrsavage View Post
The Mach .26 should actually be very easy to tune, unless you have an air leak or something.

I would unscrew the LSN and HSN all the way out so they are flush. Then maybe one full - 360 degree - turn in on both.

If adjusting the needles doesn't help, you might want to try a new plug. Try an OS #8 or Odonnell purple.

If adjusting the needles and a new plug don't help, check your clutch. If the cluth is toast it won't stay running. Also check your fuel lines, that there is no crack in the tank, etc..



For the most part the problem is I will get it half way tuned and running decent then I make a slight and I mean slight change and it is tatally out of tune. What would make it where when I give it throttle and it acclerates at a decent rate then bogs as it bogs I let off the throttle and then the engine races as if I still had the throttle down??
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Old 01-28-2012, 11:59 AM
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It really sounds like you have an air leak. The Dynamite (SH) engines are one of the easiest engines I have ever seen to tune. Check the rubber Carb boot on the slide. They have been known to crack and cause an air leak. It is a very easy, cheap fix.
The bogging and high idle sure makes it sound like a lean problem to me. Again, this can be caused by an air leak.
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Old 01-28-2012, 12:01 PM
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I've only touched the needles once when I had the Mach .26. It was the easiest engine ever to tune in all my years of RC. And I thought nothing would be easier than an OS.
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Old 01-28-2012, 01:14 PM
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Originally Posted by Wallee View Post
For the most part the problem is I will get it half way tuned and running decent then I make a slight and I mean slight change and it is tatally out of tune. What would make it where when I give it throttle and it acclerates at a decent rate then bogs as it bogs I let off the throttle and then the engine races as if I still had the throttle down??


It sounds like you are still too lean on both the high and low end. I would richen it up and see if that helps. Also I know everyone says to start with the top end and then worry about the bottom but my motor guy starts with the bottom first once the motor is up to temp. Set the low speed so that it will sit and idle for a while and when you snap the throttle it is slightly sluggish but still comes up. If it snaps up to speed instantly it is too lean. Then put it on the ground and start dialing in the high speed needle.

Also like the other guys said look for air leaks and if you haven't done so already, seal the carb and backplate with something like permatex silicone.
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