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did I ruin my engines

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truggy83

RCTalk Talkaholic
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Location
York, Pennsylvania
RC Driving Style
  1. Bashing
  2. Racing
yesterday it was supposed to have gotten up into the 50s and I figured it was a good opportunity to break in my new jato 3.3 and my new 2.5 r engine that I put in my stampede. I am impatient and most of my problems come from that. I decided to break them both in at once. Run one while the other was cooling down.

Mistake #1. I wrapped some foil around the stampedes head, started it and began the break in process as described by traxxas. After running it a few times about halfway through the tank I tested the engine temp. It seemed to be running cooler than 200 so I wrapped the head completely with another layer of foil. On the next tank I noticed it still wasn't at 200. I chalked this up as I wasn't running the engine very hard as I was only on step two (accelerate for 2 seconds up to half throttle, than break) I figured once I got up to full throttle the engine would hit 200.

I got to the last step of the break in for the stampede and it showed 217 at the glow plug. So it did seem to hit 200+ atleast on the last step of the break in. I noticed that after shutting the engine off and trying to pull the starter, it sometimes catches very hard like it is flooded but it isn't. It takes a little more force on the pull starter but it spins past this spot and seems to get easier if I pull it repeatedly. This is my first pull start so I don't know if that is common or not.

With the Jato I did the same thing although I admit I forgot to run it with the body on for step 2 (mistake #2) and I didn't check the temp on it (mistake #3). I wrapped the head the same as the stampede and figured it would hit the same temperature. I was afraid to take the foil off to check the temp as I would cause the engine to cool down and loose the heat it needed for break in. I replaced both engines glow plugs once as they seemed to have been flooded out.

I got about 1/2 through the tank 5 break in of the jato when it started acting funny. It acted as if it was running really rich and had no power. Trying to accelerate to full throttle it would bog down like it was too lean under throttle. It wasn't shifting into 2nd like it should. Keep in mind I didn't change any of the needles up to this point, they were all still at the factory settings. Per the jatos manual I leaned the high speed needle out 1/8th turn to try and get it to shift into second. It only shifted once or twice but was still acting the same way. Leaning the engine out another 1/8th turn seemed to have no affect either. It seemed to only be running worse and was almost getting to the point where it was not drivable. I replaced the glow plug and it still did the same thing. Not wanting to further damage the engine I gave up and went home.

I tried to run the stampede as it was running ok at the park and completed all 5 break in steps atleast reaching 200+ on step 5. It started up but died when I gave it throttle and wouldn't start and acted like it was flooded. Did I ruin these engines? Would trying the entire break in process again help anything or should I just start trying to tune them?
 
have you tried richening it instead of leaning it ?? ...colder weather means more rich .....factory settings are to lean for me where i live (must be the fresh canadian air ) ...i run with my HSN at least 5 turns out during the summer ..and around 5 1/2 during cold weather

you could also use the heat cycle method ...that what i did with my second 3.3

https://www.rcnitrotalk.com/forum/showthread.php?t=42716
 
have you tried richening it instead of leaning it ?? ...colder weather means more rich .....factory settings are to lean for me where i live (must be the fresh canadian air ) ...i run with my HSN at least 5 turns out during the summer ..and around 5 1/2 during cold weather

you could also use the heat cycle method ...that what i did with my second 3.3

https://www.rcnitrotalk.com/forum/showthread.php?t=42716

yes I tried richening it an 1/8th turn as well. It was probably around 48 when I broke it in. I am in pa so I am not in a high elevation area and I had the head completely wrapped in a few layers of foil. I noticed that when I went to refuel the jato that I seen some smoke in the fuel tank. Don't know if that is normal. I was trying to stick with the traxxas method for break in as they make the engines so I guess they would know the best method of breaking them in as they probably did tests to see what method worked best.
 
smoke in the tank is normal ...did you seal your engines ??? if they have an air leak , you wont be able to get a good tune ...i learned that with my first 3.3 ......do they still have good compression ?? if so , I'm sure its just a tuning issue

i would do the heat cycle method on them ....my first 3.3 was done the traxxas way ...and after a bit over a gallon of fuel , it barely had any compression left ( i figure it was caused by overheating it a few times due to lean settings..thats how i learned stock setting were not good in Canada ..lol).....anyway , i gave that engine the heat cycle and was surprised to see a noticeable gain in compression .....my other 3.3 was done with heat cycling to , and after over 2 gallons, it still has great pinch and great compression .
 
well I just got back from messing with them. The stampede with the 2.5 r ran great and I was able to get a nice tune on it in almost a tank of fuel. It accelerates great still has smoke coming out the exhaust and seems to run great. Alls I did was leaned the high speed needle out a little bit and leaned the lsn out a little as well. The jato on the other hand was a different story. I started working on leaning out the HSN. From a dead stop pulling the trigger all the way it would sputter and spit its way up to speed not even shifting. I leaned the HSN out quite a bit and that got the acceleration up and it was shifting into 2nd. It was still sputtering and cutting out on full acceleration though so I tried leaning the LSN out with raised the idle some. Than it started dying every time I would bring it in to check the temperature. The temperatures didn't seem to be too high 170 but it started sounding like it was lean and popping a little on deceleration. I ran out of fuel so I won't be able to mess with it till I get more. On another note the stampede runs crazy fast and is very unstable at high speeds. :) I broke the wheelie bar and a drive shaft but other than that had a blast with it.
 
170 is way to low of a temp for 3.3 ..they like to be around 260 to 280 ....mine even goes up 300 sometimes ..but i try not to do that often ...280 is pretty safe and runs great .....it wont run right until it gets up to operating temp
 
I will try getting it warmer and see if that does anything. I was able to pull the trigger fully back and it would just like put put like it was having a hard time getting up to speed.
 
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That's a sure sign that your LSN is set too rich. Start to lean it out just 1/16 of a turn at a time, drive it for 30 seconds to clear it out and lean it again. You might have to lower your idle screw as you lean the LSN to keep it from creeping.
When you get a good launch off the line at full throttle, any other adjustments would be on the HSN.
Keep an eye on the temp. Leaning the LSN too much could also cause an overheat.
260 to 280 is perfect.
 
That's a sure sign that your LSN is set too rich. Start to lean it out just 1/16 of a turn at a time, drive it for 30 seconds to clear it out and lean it again. You might have to lower your idle screw as you lean the LSN to keep it from creeping.
When you get a good launch off the line at full throttle, any other adjustments would be on the HSN.
Keep an eye on the temp. Leaning the LSN too much could also cause an overheat.
260 to 280 is perfect.

Thanks guys I will give it a try. Looks like I am in for a week of straight rain :angry: so it may be awhile before I get to mess with it some more. It is strange how the 2.5r in my stampede I only had to lean a little bit and it seems like the LSP on my jato 3.3 was set extremely rich or something.
 
While you're waiting for the rain to go away i would seal your engines. If you're chasing a tune, which to some extent it sounds like you are, thats more than likely the problem.
 
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