Two tuning questions

[satnerd]

Hi,

I have just finished breaking in a new Force .26 engine in my Savage and runs like hell and I'm very pleased with it
But I have 2 questions:

1. If I keep on running my car and accelerate a lot it runs very smooth and perfectely nice. Even the idle is perfect
But if I keep my engine running for about 30sec on just idle without touching the trottle it just suddenly stops.
I can easiely start the engine again and accelerate
If the engine are on idle for maybe 10seconds I don't have any problems accelerate without the engine stops
So the engine have never stopped when going from idle to full trottle - but only when idling for more than 20-30 sec without touching anything........

I suspect that this can be the LSN........and have read some places that you can adjust this with pressing the fuel line and adjust the needle so the egine runs for about 4-5 seconds
But where do you press the hose? Right after the fuel tank, right before the carb., or in the middle? I guess this is very important to have a correct result.........


2. I want to measure the temp. of my engine. Is the only way to do this with a temp gun??
I'm having a Fluke multimeter which can measure temp. Can I use this and if yes WHERE do I measure from. On the top of the engine, bottom, exchause or............

 

[CKenberg]

Hi there.
Congrats with your new nitro monster.

I think you're right about the LSN. Two things to have in mind though. I don't think it matters where you press the hose, go for the middle, but make sure you do it when the engine is warmed up.
Start with factory settings on the LSN (look in the manual) and go from there. You should be able to make it idle for several minutes, but don't expect it to idle forever - small nitro engines aren't designet for that - though some people achieve it (myself included )

Using a dedicated temp gun to check the temperature is the correct way, but until you get one, the following, less(!) precise way, can do it.

Warm up the engine and go for a full speed run - a couple of minutes should do it. Put a drop of water on the heat sink (by the glow plug) a keep an eye on it. If it boils away in a about 2-3 seconds your engine is about the right temp. If it takes longer you're probably running to rich, if it takes shorter you're probably running to lean.

Using your FLUKE, check the temp on the bottom of the heat sink, again by the glow plug.

Adjust it to the right temperature by turning the HSN in (lean) og out (rich) 1/8 of a turn at the time. Keep in mind that you should get sudden acceleration (no hessitation when hidding the forward button), and always blue smoke (but no drops of unburned fuel) from the exhaust, .

In time, you'll learn, no worries.
Claus K

PS. Pardon my english, I'm from Denmark

 

[satnerd]

Thanks for the quick reply
And you English are far better than mine I guess. I'm from Norway
My LSN are factory default already - haven't touched anything else than my HSN
What's your/others experience? Do I have to increase or decrease the needle? And how much......steps by 1/16 or........?

I understand that the temp gun is the best way to read out the engines temp, but wouldn't it be more accurate using a fluke multimeter measuring on the correct spot og the engine instead of using drops of water until I get a temp gun?

 

[CKenberg]

Actually I don't know anything specific about the Savage, my post is based on common knowledge about RC nitro engines. But if you search this forum, and other forums (ex. rcuniverse.com) as well, I think you'll come up with a lot of post where people write how they have set up carburator needles.

I guess the Fluke is okay for temperature measurering, and you can always compare it to the water drop test. You could also look for optimal temperature specifications for the engine in the above mentioned forums.

So I guess what I'm saying is, my last post describes pretty much how you should approach tuning in general terms. If you are looking for specific information, either wait for someone to post them for you here, or search the forums. I can almost promise you that your answer, along with many other "nice to know" things are out there, already pre-posted in the forums.

That's one of the great things 'bout having a popular truck )

Hope it helps
Claus K

 

[SavageRockS]

Originally posted by satnerd
Hi,

I have just finished breaking in a new Force .26 engine in my Savage and runs like hell and I'm very pleased with it
But I have 2 questions:

1. If I keep on running my car and accelerate a lot it runs very smooth and perfectely nice. Even the idle is perfect
But if I keep my engine running for about 30sec on just idle without touching the trottle it just suddenly stops.
I can easiely start the engine again and accelerate
If the engine are on idle for maybe 10seconds I don't have any problems accelerate without the engine stops
So the engine have never stopped when going from idle to full trottle - but only when idling for more than 20-30 sec without touching anything........

I suspect that this can be the LSN........and have read some places that you can adjust this with pressing the fuel line and adjust the needle so the egine runs for about 4-5 seconds
But where do you press the hose? Right after the fuel tank, right before the carb., or in the middle? I guess this is very important to have a correct result.........


2. I want to measure the temp. of my engine. Is the only way to do this with a temp gun??
I'm having a Fluke multimeter which can measure temp. Can I use this and if yes WHERE do I measure from. On the top of the engine, bottom, exchause or............

Satnerd,

I suggest you do the adjustment of the LSN simultaneous with checking of the engine temp. The fuel mixture must adhere to both the engine and outside temps, it may be more difficult to adjust when outside temp. is cold/freezing. Plus, make the adjustments after the engine has reached its optimum running temp. I always use 180-210 fahrenheit. Your engine might have a different optimum runnning temp. so adhere to it, plus make sure the fuel tank is full. Also buy a good temp. gauge, there's a whole lot of temp. guns/gauges available now and this is a must for nitro engines.

Remember that the Savage 21 fuel tank has a leaning out problem. That means when the tank is half full, you need to richen the HSN to compensate for it.

Lastly, if you wish to perform the pinching of the fuel line for idling check, pinch the line about 2 inches before the fuel gets into the carb.

Have fun!

:radio:

 

[satnerd]

Thanks a lot! I'll try doing this
But since there is close to freezingpoint outside now I'll wait to the temperature are higher
I have noticed the problem with the fuel tank. I will buy a new one without the primer since I don't need that with my rotorstart
And I'll try messuring the engines temp. with my Fluke multimeter before purchasing a temp. gun