• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Annoyed of Cutting Off.....Please Help!!!

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
B

baldie

RCTalk Champion
Messages
218
Reaction score
0
Points
0
RC Driving Style
I'm on my 10th tank and am a little annoyed because it keeps cutting off on me. 98% of the time it cuts off after idling down from WOT. 2% of time it cuts off during normal idling. I've adjusted the HSN as far as it can go without cutting off at acceleration. LSN is adjusted to the point where while pinching the fuel line, it takes about 2-3 seconds to cut-off. However I find that it does not idle up and then cut off, as it said it should do in the manual. It simply just cuts off after 2-3 seconds. I honestly have never gone through a tank without this problem. Sometimes changing the glow plug fixes it for awhile, but then it starts cutting off again. Is this an issue most people have with this engine? I need some advice/pointers as to what I can do to help this cutting off issue. I'm this close to ridding of this T-maxx and getting a savage instead. I've bashed with other savage users and they go through tanks with no problem.
 
well i had mine do that it sucked and really iritated me, thats a maxx for ya, but it sounds like your to rich if its cutting out like u described.
 
I think it has something to do with living in Fresno :D
Yes it does sound like everything is running a bit rich
Start with the LSN and lean it out just a ti bit. 1-16th of a turn to the right and run it for 2-3 minutes and see if it idles any better. Keep doing this until it will idle for 5-10 seconds without having to blip the trigger to clear it out. Once it idles better you can play with the HSN and find a good balance.

Tuning is a difficult process to learn. Once you are able to find the sweet spot and you can see how it reacts it will be easier to find it again. Sooner or later you wont even have to think about it.
 
If its running rich, then the HSN needs to be leaned clockwise correct? Well I've leaned it out to the point where it would cut off when I pull on the throttle, so I richened it a little.
 
FastEddy said:
I think it has something to do with living in Fresno :D
Yes it does sound like everything is running a bit rich
Start with the LSN and lean it out just a ti bit. 1-16th of a turn to the right and run it for 2-3 minutes and see if it idles any better. Keep doing this until it will idle for 5-10 seconds without having to blip the trigger to clear it out. Once it idles better you can play with the HSN and find a good balance.

Tuning is a difficult process to learn. Once you are able to find the sweet spot and you can see how it reacts it will be easier to find it again. Sooner or later you wont even have to think about it.
Click to expand...

According to the manual, the LSN doesn't get adjusted until the HSN is correctly set. Isn't that right? My whole focus during the tuning is the HSN. How do I know when the LSN is correctly set? I think I need some advance tips on tuning, aside from what the manual says.
 
Last edited:
If you have just broken it in, then yes, it's probably rich. Some engines also go through a 'stubborn' period during, and just after break in. Bear with it, it's only temporary.
I didn't see anything about a temperature reading, which is very helpful. Do you have a temp gauge?
Start the engine, and let it idle up to temp. How's the idle? It should run smoothly, but not fast enough to chatter the clutch, or make the car want to creep forward.
At tank ten, your LSN should be between 1/4 and 1/2 turn in from flush. That's flush with the INNER ring, not the outer ring. The outer one connects to the ball end for the linkage. When the LSN is adjusted, you might have to adjust the idle screw also.
The LSN might need some additional tweeking to throttle up to half blips on the throttle. When it responds well to half throttle, without stalling, any other adjustment is with the HSN for WOT.
All your adjustments need to be done when the engine is up to temp. Tuning an engine cold does not work well.
At WOT, look for a nice smoke trail without sputtering or stalling. If it want to quit quickly, the HSN is too lean. If it sputters, and recovers after you let go of the throttle, it's too rich.
When it seems to be running well, take temp reads to make sure you're on the safe side.
Get back to this thread with your results.
 
Okay Rolex.....just so we can be on the same page I went ahead and adjusted all needles to stock settings. HSN is 4 turns out from closed, LSN 1/4 clockwise from flush. I also installed a motor saver air filter today as well, along with a new glow plug. It started up after a few seconds and I let it idle for about 4-5 min. Idle temp varied between 150-160 degrees. During idle, I can see little squirts of fuel as well. Acceleration was sputtering just a bit but smoothed out after a second, and also smoke trailed out the exhaust. I gradually made 2 WOT passes. On the first pass as it was idling down I kept my finger on the trigger just a bit so that it wouldn't idle all the way down, for fear that it might cut off. On the second WOT pass, I let it idle down and it cut off on me. As soon as it cut off the temp reading was 190 degrees. I finished the day on that note. What should I do next? I'm looking forward to your response. Thanks again.
 
How was your acceleration from a dead stop? I think you can safely lean the LSN another 1/16 to bring the idle temp closer to 190-200.
Do that first, let it idle and check temps. Again, you might also have to adjust the idle screw. If the car creeps forward, back it off enough so that the clutch doesn't engage, yet it idles nicely.
When the idle temp holds, start doing your WOT runs and check the temps.
190 is way too rich, but the temp will come up some with the LSN adjustment.
Start to lean the HSN a little at a time, make a couple of WOT passes and check the temp again. Look for good power, good sound, a trail of smoke, and temps at 240 to 260.
Keep me posted.
 
Rolex said:
How was your acceleration from a dead stop? I think you can safely lean the LSN another 1/16 to bring the idle temp closer to 190-200.
Do that first, let it idle and check temps. Again, you might also have to adjust the idle screw. If the car creeps forward, back it off enough so that the clutch doesn't engage, yet it idles nicely.
When the idle temp holds, start doing your WOT runs and check the temps.
190 is way too rich, but the temp will come up some with the LSN adjustment.
Start to lean the HSN a little at a time, make a couple of WOT passes and check the temp again. Look for good power, good sound, a trail of smoke, and temps at 240 to 260.
Keep me posted.
Click to expand...

From a dead stop there was a little stuttering and alot of smoke. I will try your adjustments on weds, which will be the next time I run my maxx. I'll keep you posted as to what happens then. Thanks Rolex!
 
If you had stuttering, a lot of smoke and temp around 150 at idle, you need to lean the LSN. So, follow my instructions, above, and let us know how it runs.
 
Hey Rolex.....I leaned out the LSN...let idle for about 5 min. Took several temp readings and I got 191, 195, 193 degrees. So I guess you can say it stayed in the 190-200 range. Just want to note though that during idle, it cut off twice but I was able to start it up again right away. I made 3 WOT passes and after each pass I press the brake to bring it to a complete stop. As it came down from idle, it cut off. It cut off 2 out of the 3 passes. After the 2nd cut-off I couldn't start it up again. I haven't made adjustments to the HSN yet. The temp reading I got after the passes was between 210-230. What next?
 
Stalling during long periods of idle is usually from "snotting" up with oil. You need to pick up the car and give it a couple of short throttle bursts to clear it out.
While it is idling, hit your brakes completely. Does the idle slow down or cut out? If it does, you still need to check the mechanical adjustment with the idle screw to make sure it CAN NOT close any more when brakes are applied.
Also, lean your HSN another 1/16 turn in to bring your WOT temp up a little.
Keep looking for good acceleration, a smooth sound, and a smoke trail.
 
Rolex said:
Stalling during long periods of idle is usually from "snotting" up with oil. You need to pick up the car and give it a couple of short throttle bursts to clear it out.
While it is idling, hit your brakes completely. Does the idle slow down or cut out? If it does, you still need to check the mechanical adjustment with the idle screw to make sure it CAN NOT close any more when brakes are applied.
Also, lean your HSN another 1/16 turn in to bring your WOT temp up a little.
Keep looking for good acceleration, a smooth sound, and a smoke trail.
Click to expand...

How do I know when the Idle screw will be correctly set? Should I adjust clockwise or counterclockwise?
 
Clockwise will raise the idle. Keep twitching the trigger while you do it, so you can hear how it changes. Was it cutting out when you hit the brakes?
That's a common problem when the idle is set with the trim knob, and not properly set with the idle screw.
 
Hi, Guys
I am a newbie to RC world again the first time I got started it was a cox car many years ago.
I just wanted to say you guys are great it does not mater how many time someone asks the same question there is always an answer from someone.
Ok on to why I am here just a couple of things to look for I was having about the same problem as baldie but I found that my slide on the carb was not going all the way closed to the idle screw until lidling a little so when I was adjusting the carb it was not hitting the ilde screw and it would quit I fixed that problem. But than after adjusting the idle it would creep like it was in gear so I found that the clutch spring was stretched out so the clutch was always engaged. I fixed that and now it is all most prefect a little more adjusting and good to go.
Keep up the good work everyone.

Thanks, Rick
 
Welcome to RCNT, Rick. We're all here because there are so many members in the know who are willing to help out. Feel free to ask questions or pitch in and help.
 
Rolex, mine does the same thing once in awhile. The servo is not bringing the carb back to idle, but the idle adjustment seems to be adjusted properly as it is stopping it from moving. It would be nice if Traxxas put a throttle return spring on these things to ensure the throttle got back to true idle position everytime. My RS4-3 SS does the same thing.
 
Rolex, I want to add a throttle return to my tmaxx as well, and I was wondering if you could post a pic of how you mounted yours.

adrian
 
My setup won't work for yours. I upgraded to the 2.5, mounted the tower in a different place, and reversed the carb and linkages.
You'll have to wait for someone else.
 

RC Builds

Back
Top