stunthanger.com
Engine basics => Engine set up tips => Topic started by: frank mccune 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
-
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
-
Hello Brett:
That is what I thought.
Thanks for the prompt answer.
Stay well,
Frank
-
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
-
Petrol and spark ignition also 4/2 quite nicely, just ask some vintage flyers.
Chris.
-
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
-
Lawn Boys shake too much for a profile .
Brad
-
Lawn Boys shake too much for a profile .
You can never have too much power!
Brett
-
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.
-
Geeze Brett , now everone'll want one . theyre only $ 400 new . F2B will never be the same now .
(https://i.ebayimg.com/images/g/5REAAOSw-HxdBvDa/s-l1600.jpg)
(https://i.ebayimg.com/images/g/C6UAAOSwTUZdBvDu/s-l1600.jpg)
https://www.ebay.com/itm/254266398483?hash=item3b33755713:g:5REAAOSw-HxdBvDa
-
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
-
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.
-
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