Tuning issues

[Jammy473]

This is my first nitro rc and I'm trying to tune it. It slows down after half acceleration, and I'm not sure whether it's too lean or rich. I have been changing the HSN all day but can't get it to go fast.

I decided to richen it all the way out (HSN flush) and start winding it in 1/8 at a time but got it all the way in without hitting the right spot.

Also when I richened it out there was heaps of splattering fuel from the exayst but still not much smoke. Also the engine gets really hot.

Btw it's a 1/16 scale truggy.


Any ideas how to tune this thing? Any help appretiated

thanks

 

[alien13]

What motor? Kind of car? And if you have fuel splattering out of the exhaust, it's way too rich.

Try this. Turn your needles all the way in. Back them out about 2.5 turns. Start with that. Before you start it, tip the car forward, then to the side that the exhaust nozzle faces, and dump the fuel out of the exhaust. Repeat until it stops coming out. Pull the glow plug, crank the motor to make sure it's not flooded. While it's out, test the plug with your heater, make sure it glows red in a hurry. If so, put it back in, try starting it.

If you get it running, get it up to operating temps. Should be about 190-230 degrees next to the glowplug. Though running rich, you aren't likely to get there. Lean out your high end by 1/8 turns, test after each adjustment. Keep watching your temps. Once you get the high end tuned, go to the low end.

If at any time you pull the throttle and it bogs down, chances are you are way too rich still.

 

[2revo1maxx]

What motor? Kind of car? And if you have fuel splattering out of the exhaust, it's way too rich.

Try this. Turn your needles all the way in. Back them out about 2.5 turns. Start with that. Before you start it, tip the car forward, then to the side that the exhaust nozzle faces, and dump the fuel out of the exhaust. Repeat until it stops coming out. Pull the glow plug, crank the motor to make sure it's not flooded. While it's out, test the plug with your heater, make sure it glows red in a hurry. If so, put it back in, try starting it.

If you get it running, get it up to operating temps. Should be about 190-230 degrees next to the glowplug. Though running rich, you aren't likely to get there. Lean out your high end by 1/8 turns, test after each adjustment. Keep watching your temps. Once you get the high end tuned, go to the low end.

If at any time you pull the throttle and it bogs down, chances are you are way too rich still.

Do not go with only 2.5 turns out, you'll fry just about any engine out there. Find out what the factory settings are and go with that. Before you try to run it again check the engine for cracks or any sign of leaking fuel. If it's good then try to run it. Wouldn't hurt to make sure the glow plug is either new or at least glowing. If that checks out then you may have screwed the needles in too tight, which can destroy there ability to meter fuel correctly. Take out the hsn and see if the needle is all goobered up. Also running too lean will cause a bog that is even worse sounding than a rich bog. I really think you have a major air leak somewhere.

 

[Metalhead Matt]

I'd seal that engine before even running it again. New plug and fuel lines. Once it's air tight, set it to factory settings, then lean each needle 1 hour. Get it warmed up and tune it from there.

 

[Scrogg]

If this engine has a low speed needle, that's where you are messing up. Just use the HSN to get a decent top speed, nothing screamong fast. Then adjust the LSN in small increments until the acceleration gets good. Then lower your idle speed with the idle screw. Then adjust the throttle linkage so that the carb slide is resting on the idle adj. screw stop with the throttle trigger at idle. Forget the temps for now, just get it to run good with a healthy smoke trail. Nitro engines do not smoke at idle, they just spit out the oil. I'm 99% sure you are overleaning the HSN and the LSN is too rich. Acceleration comes from the LSN. I hope your engine has a LSN, most micro engines don't. They are pretty much impossible to tune correctly. Put a new glow plug in it first, this is very important. Running an engine too lean and hot will push the glow plug element up into the housing, ruining it. It may still glow bright and run, but it will never tune right. Toss it.

 

[alien13]

Do not go with only 2.5 turns out, you'll fry just about any engine out there. Find out what the factory settings are and go with that. Before you try to run it again check the engine for cracks or any sign of leaking fuel. If it's good then try to run it. Wouldn't hurt to make sure the glow plug is either new or at least glowing. If that checks out then you may have screwed the needles in too tight, which can destroy there ability to meter fuel correctly. Take out the hsn and see if the needle is all goobered up. Also running too lean will cause a bog that is even worse sounding than a rich bog. I really think you have a major air leak somewhere.

Actually, that's about what my factory settings are on a Speed-NT. 2.75 turn out to be exact.

 

[Metalhead Matt]

It doesn't matter what the factory settings are on your Losi. Different brands very. Your suggestion is just a shot in the dark. Google your models factory settings when unsure.

 

[Jammy473]

I cannot find the factory settings anywhere... It's an nb16t if anyone can help

ps how do I check for leaks?

Thanks

 

[Metalhead Matt]

What kind of truck is it? Seal the carb throat, header, backplate and hsn housing with sensor-safe, high-temp copper rtv. Make sure the head bolts are tight. Make sure the fuel lines are good and that the tank cap is sealing. Also check the exhaust coupler for leaks. After all that, fire it up and it should run cooler and tune in.

 

[Jammy473]

Thanks metalhead matt. I will post if I have any success after sealing the engine

 

[trxrustler10]

i have a traxxas nitro rustler 2.5 and it idles very high and spits gas out. it also feels hot and i also set all my needles to factory settings, exept the iss. it either idles high or bogs and wants to stall, no inbetween. any suggestions? also its only 2 months old. :\

 

[Metalhead Matt]

Read post 9.