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Author Topic: 4-2-4 engine run sans nitro, possible?  (Read 1303 times)

Offline frank mccune

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4-2-4 engine run sans nitro, possible?
« on: May 11, 2021, 10:55:02 AM »
       Hello All:

        Is it possible to have an engine produce a 4-2-4 run sans nitro.

         I have my thoughts, what are yours?

         Tia,

          Frank

     

       

Offline Brett Buck

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #1 on: May 11, 2021, 11:07:18 AM »
       Hello All:

        Is it possible to have an engine produce a 4-2-4 run sans nitro.
     

     

  Of course, why wouldn't it?  The best/most successful large 4-2 break engine is the Discovery-Retro, it has problems in some conditions even on 5%, and runs fine on FAI fuel.

   There is nothing terribly magical about 4-2 breaks, I am not sure why it seems so mysterious to people.

     Brett

Offline frank mccune

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #2 on: May 11, 2021, 02:18:05 PM »
     Hello Brett:

     That is what I thought.

      Thanks for the prompt answer.

      Stay well,

      Frank

Offline RandySmith

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #3 on: May 11, 2021, 05:11:34 PM »
       Hello All:

        Is it possible to have an engine produce a 4-2-4 run sans nitro.

         I have my thoughts, what are yours?

         Tia,

          Frank

     

     

Frank  you can get a  no nitro 4/2 run on many many  engines,  Fox 35   ST 46  ST60   Aero Tiger  any  PA   and  a host  of  other  engines

Randy

Offline Chris Wilson

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #4 on: May 12, 2021, 05:08:31 AM »
Petrol and spark ignition also 4/2 quite nicely, just ask some vintage flyers.
Chris.
MAAA AUS 73427

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 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Brett Buck

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #5 on: May 12, 2021, 08:47:05 AM »
Petrol and spark ignition also 4/2 quite nicely, just ask some vintage flyers.
Chris.

   A Lawn-Boy lawn mower (the older 2-stroke version) would very happily break from a rich 2 to a lean 2 when it hit higher grass. You had to really screw up the setting to get it to misfire at no load, although you could do it, then you got a 4-2 break.  That with constant spark timing, constant fuel supply pressure, constant everything else - except for varying the load.

   QED.
   
    Brett

Offline Brad LaPointe

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #6 on: May 12, 2021, 08:59:56 AM »
Lawn Boys shake too much for a profile .

Brad

Offline Brett Buck

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #7 on: May 12, 2021, 09:11:05 AM »
Lawn Boys shake too much for a profile .

You can never have too much power!

    Brett

Offline Chris Wilson

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #8 on: May 12, 2021, 03:18:53 PM »
Would love to know if an OS Wankel engine might hold a 4/2 setting.

The free flight spark boys experienced the 4/2 probably before anyone else but had no idea what to do with it.
Go figure.
Chris.
MAAA AUS 73427

You have enemies? Good. That means you've stood up for something, sometime in your life.
 Nothing in life is so exhilarating as to be shot at without result.  It's not enough that we do our best; sometimes we have to do what's required

Offline Air Ministry .

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #9 on: May 12, 2021, 09:59:36 PM »
Geeze Brett , now everone'll want one . theyre only $ 400 new . F2B will never be the same now .





https://www.ebay.com/itm/254266398483?hash=item3b33755713:g:5REAAOSw-HxdBvDa

Offline frank mccune

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #10 on: May 13, 2021, 02:40:31 PM »
      Hi Brett:

       I will bet that the sound that you hear on the Lawnboy changing rpm is due to the action of the governor!  I have never heard a Lawnboy run in a four cycle. Perhaps I did not recognize the four cycle sound.

        As I type this, I am rebuilding a 5269 and the next project is short blocking a 5029 Brickhead.  I just can not say no to a D engine.  To me they are the greatest mower ever sold.  My wife trims with a 19” 5239 and loves it!

         In any case, stay well,

          Frank McCune

       

Offline Brett Buck

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #11 on: May 13, 2021, 04:51:49 PM »
      Hi Brett:

       I will bet that the sound that you hear on the Lawnboy changing rpm is due to the action of the governor!  I have never heard a Lawnboy run in a four cycle. Perhaps I did not recognize the four cycle sound.

     

    Does the same even with the governor defeated. And I have intentionally set it super-rich to convince myself that it was just the load (45 years ago, when I still had grass to mow....).

    Brett

p.s. it's just a giant version of an Ohlsson 23 sideport - which can be induced to do the same thing on ignition.

Offline RandySmith

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Re: 4-2-4 engine run sans nitro, possible?
« Reply #12 on: May 16, 2021, 11:07:30 AM »
   A Lawn-Boy lawn mower (the older 2-stroke version) would very happily break from a rich 2 to a lean 2 when it hit higher grass. You had to really screw up the setting to get it to misfire at no load, although you could do it, then you got a 4-2 break.  That with constant spark timing, constant fuel supply pressure, constant everything else - except for varying the load.

   QED.
   
    Brett

LOL  my  2 stroke  leaf blower  will run a  4/2,  when i adjust the carb mixture  for the different petrols.. it will go into a  4 stroke, and i can set it where it  runs  4/2 back n forth right on the  verge.  It will  kick from 4/2 when you load it with full throttle

Randy


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