Tuning due to Engine Cut-off?

[jjbtcp]

I only just broke in the engine and started tuning my Savage 3.5. We adjusted the High speed needle. It runs a lot better now.

I get it going really fast, but when I reach full throttle it slows down. Also, when it's idle, it still moves.

We adjusted the idle needle, but if you open it enough so it will start without applying throttle it still moves. And if you close it just enough to make it stop moving then it won't start without applying throttle.

Any tips of what I should do? Like weather to make it more lean or more rich?

Regards,
- Joshua

 

[Parputt537]

If it is cutting out at high RPM you are too Lean.

Read This for some excellent tips: http://www.rchobbies.org/cars_eng-tuning.htm

Having to apply a little throttle to start is the norm. About 10% is usually the sweet spot. Set your idle screw once the truck is up to operating temperature. Use the throttle trim nob in the transmitter to give a little throttle (10 - 20%) to start when cold. Once she is warm you may still have to give a little throttle to start, but not as much when she is cold.

Remember, all settings should be done when the truck is at operating temp.

 

[jjbtcp]

If it is cutting out at high RPM you are too Lean.

Read This for some excellent tips: http://www.rchobbies.org/cars_eng-tuning.htm

Having to apply a little throttle to start is the norm. About 10% is usually the sweet spot. Set your idle screw once the truck is up to operating temperature. Use the throttle trim nob in the transmitter to give a little throttle (10 - 20%) to start when cold. Once she is warm you may still have to give a little throttle to start, but not as much when she is cold.

Remember, all settings should be done when the truck is at operating temp.

It's cutting out at low RPM. Which means I need to make it more lean? It has been running better since we adjusted the high speed needle to be more lean. I'll post the link to my Youtube video when it's ready on there.

 

[jjbtcp]

Click the link above to watch a clip of me driving it today. What do you think? Need to be more lean or rich? Most of the time through the clip it's running at full throttle.

 

[Racer 1966]

Opening the throttle to start it is normal as mentioned above, I use the trim on the radio open it up until the engine is warmed up then trim it back.

My computer is too old to watch vids from the net, but you may need to adjust your lsn a bit. Could be too lean on the low side. The lsn adjustments are usually very small.

You can do a pinch test on the fuel line to help judge the setting on the low end and check temps the get the top end set. If you pinch the fuel line close to the carb while idling, how long does it run before it dies? What temp is the engine running at?

 

[jjbtcp]

Opening the throttle to start it is normal as mentioned above, I use the trim on the radio open it up until the engine is warmed up then trim it back.

My computer is too old to watch vids from the net, but you may need to adjust your lsn a bit. Could be too lean on the low side. The lsn adjustments are usually very small.

You can do a pinch test on the fuel line to help judge the setting on the low end and check temps the get the top end set. If you pinch the fuel line close to the carb while idling, how long does it run before it dies? What temp is the engine running at?

I probably won't get to run again for the next 2 weeks because we are going on holidays in 2 days. To stop the engine though we have been pinching the line. the only thing I can tell you is that if we pinch it about half way along the tube it keeps going for about 5 seconds.

Today I bought an Infrared thermometer. So I will measure the temp and pinch the line right near the Carb, if i get a chance. If not, I'll PM you after I get back from holidays and tell you what my results were. Also, the fuel the hobby shop told me to use it only 10% nitro. I only just found out in my other thread that for my Savage it need 20-25% nitro (which is also recommended in the manual).

 

[jjbtcp]

To break in my engine, all I've done is drove it around going no more than 50% throttle. Could I gave damaged the engine? Or is it alright to do it the way I did?

 

[Rolex]

You haven't done any damage, but I'm sure you haven't done anything to break it in properly, either.
Get the 20% fuel and follow the manual instructions. Don't do this till you have a temp gauge, since breakin is ALL about expansion and contraction of the metals due to heating and proper cooling.
When you have the right fuel, check back and we'll give you the info on what to do.

 

[Parputt537]

http://www.youtube.com/watch?v=xKuj3c0yrjI

Click the link above to watch a clip of me driving it today. What do you think? Need to be more lean or rich? Most of the time through the clip it's running at full throttle.

OK, I watched your video.

You have NO smoke coming from the exhaust which means you are WAY to lean as I stated above. READ the article in the link I posted and re-tune the truck. If you keep running the truck the way it is tuned you will fry the motor.

 

[jjbtcp]

I was told I need to richen my lsn and lean my hsn. That right?

 

[Parputt537]

I was told I need to richen my lsn and lean my hsn. That right?

jjbtcp, Please forgive me in advance if I sound rude, but have you even bothered to read the article I linked to above. It is not as easy as you are making it sound. There is no way someone can tell you to richen the LSN and lean the HSN just by what you are saying and seeing the video. I can tell you that your overall tune is LEAN just by not seeing any smoke from the exhaust. Read the article I posted, set your needles back to factory and start all over.

Good Luck

 

[jjbtcp]

jjbtcp, Please forgive me in advance if I sound rude, but have you even bothered to read the article I linked to above. It is not as easy as you are making it sound. There is no way someone can tell you to richen the LSN and lean the HSN just by what you are saying and seeing the video. I can tell you that your overall tune is LEAN just by not seeing any smoke from the exhaust. Read the article I posted, set your needles back to factory and start all over.

Good Luck

Yes, I have read the article. Printed it out too. Read through it twice, the second time with my Dad. The guy at the Hobby shop told me what to do, after I described what was happening. But I guess the Hobby shop guy really is a loser.

Plus, I havn't got a chance to give it a run since you posted that article. I'm going to today and it will be the last chance I will get for 2 weeks. That's why I'm trying to find out as much as I can so my final run today I can get it tuned as best I can. But then in the end I still have to get 20% Nitro fuel, and I won't be able to get that until after I get back from holidays.

 

[Parputt537]

My suggestion at this point would be to leave it alone until you get back from holidays. You are rushing a process that needs time. I have tried to rush things like this in the past and all it does is frustrate you. Remember, this is a hobby and should be enjoyable. Leave the truck alone until you have time to mess with it.

Have fun on holidays.