rafa26

Yesterday i was fixing my shed and organizing some machines like snow plower, chain saw, pressure washer and for last i found a Husqvarna trimmer outside the shed, a 2 cycle 24.5 cc, maximum power speed 9,000 rpm.

The Husqvarna trimmer was used for the last time 4 months ago and was sitting behind my deck (yes, it was there for 4 months getting sun, rain and snow) because i forgot to put it back inside and that is a 4 years machine.

Ok , here comes the good part,

1) Pressed 10 times on the gas injector
2) Turned the choke
3) Pull the cord 5 times and i hear the wonderful sound of the engine working, a little smoke on the begining but after 2 minute the engine was at normal temperature and running flawlessly at all rpms.


Needed a new tune ??? What's that ??? Needed a new Spark Plug ? NOOOO. The machine came tuned by Husqvarna from factory and i never had to turn one screw on the carburator to make it run better, always easy starts and nice power.


With all respect for the Nitro guys, a lot of people like to go to play with theirs cars but the first think they have to do is to open a tool box and loose hours fixing and tuning their engines and if they like i respect that but i realy prefer to go to play, pull the cord and start acellerating as soon as the engine is warmed up.



Thanks .

losifiend

Not true for all nitros. I have 4 gallons through my LST2 and have never tuned it once after initial break in. Yes, I have chnged glow plugs but never once have I had a probem with it starting eather. It all depends on the individual and engine I guess.

vtl1180ny

If you've never tuned it you are not running it at it's optimum settings... You probably have it running a bit rich and have never experienced its true potential... No matter what the brand of nitro engine is, it's going to need a bit of tweaking every day...

rafa26

Couldn't agree anymore.[sm=thumbs_up.gif]

stempak

I high performance gas 2stroke like what is used in these cars needs to be tuned just about every day you run them. No they don't need to be tuned as much as a nitro. But still need to be tuned. They also will sometimes not run for no apparent reason just like a nitro. But the gassers are definately much easier and better running as a hole. Not to mention the how long they run 30-45min as 10-15min nitro, aswell as not being 20-30 dollars a gallon.

rafa26

I think "every-day" as you mentioned is an exaggeration

vtl1180ny

Nitro fumes make me sick...

jimjeep

That is no exaggeration! For any internal combustion engine to run at peak efficiency and power the "charge" (air/fuel) mixture must be adjusted not just on a daily basis but sometimes more than once a day depending on changes in the ambient air conditions. This is well known in racing circles and is also the reason why all modern cars use engine control computers to control the combustion mixture as well as the ignition timing. Small changes in air density from tempature, barometric pressure, humidity, etc... will require changes in engine tuning. Nitro engines are just much more sensitive to these changes compared to gasoline engines. I love that about my gasser besides the fact that I don't need to worry about having a charged igniter, nitro fuel going stale, or after-running it. I own 4-5 nitro's and 1 gas and I say Gassers Rule!

rafa26

I think you are talking about the Formula-1 of the Gas race trucks where half tenth of a second makes difference. How different is the motor of my trimmer to the motor of a gas truck ? Why did the trimmer worked flawlessly after 4 months ??

jimjeep

The trimmer motor will of course still work well. That is the great advantage to gasoline not being as sensitive to tuning issues as compared to nitro. If a nitro engine sat outside that long it would likely be all gummed up and wouldn't start!, but gasoline engines although less sensitive to changes in air density also need tuning adjustments to run at peak efficiency and power. If you run your engine on a cool dry day and then run it on a hot humid day without adjusting the engine's tune it will not run the same and may not produce the same power. The fuel is a fairly constant variable but air (or more properly oxygen) density changes with the weather and therefore changes how much fuel must be in the mixture to achieve a full and even burn in the combustion chamber. Too much fuel and it isn't all burned (also displacing air which could have burned more fuel) Too little fuel and you've lost the potential to burn more with the availiable air that got wasted out the exhaust. You might not notice the difference unless you run on a constant surface all the time like a racetrack, parking lot, or lawn. When one day you wheelie like mad and on another day you don't on the same surface it's not by coincedance it's tuning.

Isle of Wight Basher

Yep,
that's all fine in theory, yet in the real world these small (very basic) 2 stroke petrol engines have more then enough power that small fluctuations in air density, and temperature don't require you to re-tune.

rafa26

Agree 100%.

jimjeep

Yes, I've only tuned mine once. Set it and forget it. If I were competitively racing onroad it would be a different matter, but for off-road racing and bashing the change wouldn't even be worth the effort. You don't even need to re-tune a nitro engine after break-in, although the effect of changes in weather will be more noticeable. That's just one of the reasons why my gasser is the favorite. Gotta love the gas! Now, if I can only get my weed trimmer to hold a good tune....

ttoks

if you brought large scale RC engines up to even the level of performance quality chainsaw engines are, you would be notusing much bigger differences in performance from day to day then you do with current large scale engines, the compression in current engines is far two low, 4 head bolts and 11:1 compression minimum is what's needed.

Husqvarna are a quality brand, my old man bought a 60CC 12 hp husky chainsaw 12 years ago, tuned it to a dark, almost chocolaty brown spark plug and hasn't tuned it since, from day to day it's very easy to tell the difference in performance, particularly with the day's we're having at the moment (one day will be 30 degrees C, the next will be 8 and raining)