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Engine basics => Engine set up tips => Topic started by: frank mccune on October 15, 2016, 07:01:00 AM

Title: Engine burbles or misses after changing direction??
Post by: frank mccune on October 15, 2016, 07:01:00 AM

       Hello All:

       What would cause an engine to slow down and misfire after changing directions? This happens whether upright or inverted.  The engine runs a perfect 4-2-4 until there is a change in direction.  It takes about 2 seconds for the engine come back to a good run.

      The set up is an O.S. .40S in a Green Box Nobler, 11X6 prop and 59'-6" lines.  Fuel is 28% oil, 50-50 and 12% nitro.  The glow plug is a Fireball med. RC.  Perhaps a change of plugs would help the problem.

     Other than this problem, this is a wonderful flying combination! The engine other than being obsolete, is a great engine!  Despite being ringed, it is very easy to start and needle.

     I just had a revelation, perhaps the tank is NOT an uniflow as I was told.  I will try it today WITHOUT  capping the overflow tube and see if the problem abates.  I will post my finding later today.

                                                                                                                                  Thanks for reading,

                                                                                                                                   Frank McCune

                                                                                                                                   

     
     

Title: Re: Engine burbles or misses after changing direction??
Post by: RandySmith on October 15, 2016, 10:45:00 AM

is this the plain or ball bearing  one?  if ball bearing  you should drop the  oil down to 23 or 24%
and either  way you should drop the  nitro down  to under 10% and try that

Randy

Title: Re: Engine burbles or misses after changing direction??
Post by: Motorman on October 15, 2016, 12:19:25 PM

Allot of those Fireball Mediums had bad seals in them. Try a better plug.

MM

Title: Re: Engine burbles or misses after changing direction??
Post by: Brian Hampton on October 15, 2016, 04:45:09 PM

Quote from: RandySmith on October 15, 2016, 10:45:00 AM

is this the plain or ball bearing  one?

With these first version H-40's most had just a single rear ball race except for the 40P and 40R. Easy way to tell at a glance is with the prop driver. Twin BB engines have a longish spool type driver while the rest have a drive washer that extends back inside the crankcase where a bearing could be fitted so appears quite short.

Title: Re: Engine burbles or misses after changing direction??
Post by: frank mccune on October 15, 2016, 04:55:00 PM

       Hi All:

       This engine has one ball bearing located in the rear of the crankshaft.  It is named the .40 S which was designed to be a control line stunt engine hence the S under the .40 on the crankcase. The engine is circa 1971.

       I did not fly this engine today.  The next time that I go flying, I will fly it.

                                                                                                                          Thanks for all of the replies,

                                                                                                                          Frank McCune

Title: Re: Engine burbles or misses after changing direction??
Post by: RandySmith on October 15, 2016, 04:59:45 PM

Quote from: frank mccune on October 15, 2016, 04:55:00 PM

       Hi All:

       This engine has one ball bearing located in the rear of the crankshaft.  It is named the .40 S which was designed to be a control line stunt engine hence the S under the .40 on the crankcase. The engine is circa 1971.

       I did not fly this engine today.  The next time that I go flying, I will fly it.

                                                                                                                          Thanks for all of the replies,

                                                                                                                          Frank McCune

Put a new   RC HOT  plug in it, and use 24%  1/2 synth fuel   next time either  5 or 10%  ,   this time of year 5 should plenty

Randy