One revo is bogging down at take off and other goes at slow speed fine then bogs when you try to go fast, sometimes it will take off and some times it will bog and die.
Read over tune articles and found nothing
its hard to tell if its too lean or too rich your hsn and lsn without hearing the sound of the engine. cause too lean it will bog and sometimes it will die same if it is too rich it will bogs then dies. better start to tune your engine on a richer side then start lean it out until it runs on high speed well then start to adjust again your lsn. tune first hsn then lsn.
The following is an except from the Nitro Tuning Tips and Flow Chart thread that is stickied at the top of this forum found HERE.
Here are some symptoms of an engine that is running too rich:
1. A lot of blue smoke from the exhaust pipe.
2. A lot of unburned fuel exiting the exhaust pipe. 3. Idles properly, but bogs down an dies when the throttle is full applied.
4. Never reaches full top speed.
5. Engine temperature is too cold (e.g. below 200 F degrees)
If you want to try a different tuning guide that may be a little easier to follow than the flow chart you could try Robin's tuning guide found HERE.
The one that will bog and die after take off probably needs a new Glow Plug when they get weak they will do this. Had the glow plugs partially fail many times in the past.
This is the Worse case scenario for the other one. If the engine ever got a few specks of dirt in it this is also a symptom of scratches in the piston or piston wall. It will run fine until the engine heats up and the metal expands then it will just bog and die then when you let it cool and restart it same thing happens. Best thing to do if you suspect this happening is pull out the engine clean it really good and pull the head off then inspect the piston sleeve on the engine for scratches.
I have only once allowed dirt into one of my really expensive race engines because I ran a cheap air filter a few times at the track dirt got in and it would run a few laps then bog and die. Once I pulled the head off I saw scratches in the piston wall.
Other truck is new maybe one tank since breakin so hope it not the motor.
Returned carb back to stock setting and will retune when rain stops in a few days
New engine breakins always stall on the first few tanks this is normal. You will not see a consistant idle until after the 4th or 5th tank of fuel. The way to avoid it is raise your idle during break in. You can do this on the transmitter. I have had 6 traxxas engines to break in over the years. And 2 out of 6 needed a new glow plug during the procedure. At least now you have provided more information
It's not the plug, but it's always good to have a spare. I think it's a rich lsn and lean hsn.....aka false tune. Read this article from ERCM: https://www.rcnitrotalk.com/forum/showthread.php?t=94326, it will help you get the low end dialed in.
I would set the hsn at 4.5 turns and start from there, it's always good to start rich and work your way to a good tune.Try to remember that even a well tuned engine will run rich until it warms up.
Made a few passes with it after returnin to factory setting and closing down idle gap it runs like a top.
Now to just fine tune it anf then start on the other one.
Thanks for the hel
---------- Post added at 7:43 PM ---------- Previous post was at 7:43 PM ----------
Glad you were able to get it running properly. Engine Break in periods are the most trying times. The engines tend to stall often and not run really well until after the 5th or 6th tank of fuel.
Now you will have fun but as a note Slide Carbs require tuning almost every time you take them out if there are drastic changes in the weather. Every first tank you run it may require a bit of tweaking for the day to get it to best performance.
Some days you will have to richen the mixture than others you may have to lean it. Traxxas has a chart that I will share with you all. and this does not apply to just Traxxas Engines.
On the other revo I tried to adjust idle screw but the slide doesn't move wjen I turn it.
Only way I could close up the gap was with low mixture screw.
so having a hard time getting it to tune. When you make a high speed pass and stop with breaks it idles high for a bit before it idles down.
Beginning to think could be an air leak, now that I think abiut it this started after a telephone pole jumped in front of the revo catching the front left tire breaking toelink.
It's your throttle linkage keeping you from closing the gap any further. Use a small paper clip to set the gap it works pretty good. Idling high when you're braking is a sign of a lean hsn.
Set it thickness of paperclip? Will adjust linkage when I get home, never occurred to check it
The simple things are always last to think of. Lol
thanks
