I finally got some fuel to break-in my brand new OS1.40RX. Things are not good. When I start her up for the first time tonight she ran horribly. Really hammering away. Spewing gas from carburator. Running 300% to rich I think.

I was using 0% Nitro FAI fuel because my manual says to break her in with 10% or less Nitro. The only other fuel I have is 15% Nitro.

Engine was set up just like the manual stated: 1.5 turns on HS needle and leave everything else as set by the factory.

Does anyone have any ideas. Could the 0% Nitro be the problem. Thanks.

Splais, sounds really rich to me. What prop, pipe are you running. I broke mine in on 15 mach 7, just kept it a bit on the rich side for the first gallon. I also found if my pipe length is too short, my midrange goes so rich that it is unusable; had to stretch out the pipe about an inch. Am using Macs header and Macs 140-180 pipe, Apc 16 1/2-13-w and 17-12----17-13 standard, at around 7600-8000 rpm. Try leaning out the top end a bit, and see if she cleans up, if not, try leaning in the low speed screw a wee bit at a time.

Also. just measured, and am 29 1/2 inches from glow plug to baffle in macs tuned pipe, and O.S.--F--glow plug a must.

Hope this helps a bit.!!

I would follow the OS manual word for word, I broke mine in on 10% with an os pipe and header ( $360) and a 16" prop. We picked it up cheap because the guy who had it first hated it couldn't get it to run nicely. 47 flights later and it will beat any YS for power ( not the DZ yet though) and I wouldn't trade it for anything.

Matt

OK, a few more facts. OS#A5 plug (recommended by manual). I do also run and have Mach7 15% fuel. I have the standard and recommended OS tuned pipe. I'm trying to run an APC 17x12 prop.

Running rich, lean her out??? 1.5 turns should not be THAT rich should it? It is running REALLY, REALLY bad. Not even close to actually running or being on the pipe. It's just banging along, barely, and spewing gas out the carb.

Ok, and a few more facts after that! OS--F plug a MUST! The 5 just doesn't cut the mustard, runs too cold. Midrange goes to pieces.

I normally run mine 1-1/5 to 1-3/4 turns out, but the manual settings are just a starting point to get the thing to go. Change out the plug, put in an F, stretch the pipe out an inch, start it up at 1-1/2 turns, and then try leaning it out from there. I have found that the OS pipe, here at 3000 ft alt, still needs to be stretched out a bit to run the big props. Works at stock length ok with a 16-13 or a 16-14, but I found that with a 14 pitch prop, couldn't get the plane to slow down enought for me.
The 17 inchers give you good braking and the 13 pitch gives really consistent speeds. But, you have to stretch out the pipe to get it to work! The midrange just will not work at shorter pipe lengths with the big props.

I have also tried backing out the pump, with some success, but leave that alone for now. Voids the warranty and all that.

Short of any of that working, poss pump problem? But wouldn't think so at this point.

Keep us posted.

OOPs, forgot to mention, that you should be ok running 15 percent in her to break in, just keep it a bit on the rich side once you get it running. This will also help the idle and the midrange running along with the hotter plug. fs

I broke mine in using 15% also with no issue. If it's the stubby needle valve your using, you could be too far open. Try the skinny needle, it's a little less sensitive. I broke mine in on the same prop I fly with (15.5 x 12 four blade). I'm with everybody, lean it out. Plus make sure the pipe is longer than necessary for break in.

I would like to thank everyone for their help. My 1.40 is now running GREAT!

I made three changes: (1) I read the fine print in my manual, says A5, 8 or F. I switched to an 8 because I was out of F's; (2) I switched to the 15% mach7 I usually use; and (3) I switched the HS Needle to the optional long taper needle. I think this is what made the biggest difference.

Anyway after I made all those changes I put the starter on her and she started right up and purred like a kitten.

GREAT.... now go flyflyflyflyflyflyfly!!!!!