Meziked

Hey all,
OK I have a 2.5r in a revo. Broke in at 4 turns out per Traxxas. Started leaning her out and she would bog down and die instantly at full pull. I was thinking too hot, checked her and 240..... too cold.... so im thinking way to rich and i must have tweaked the wrong direction. so i went 1/4 turn back..... same situation..... so I took the needle all the way in and back out 4 tunrs.... same situation, now its impossible to start. So Im thinking, yeah I ate a glow plug. Pulled the plug and hit the starter.....glowed bright red like it should in seconds. De-flooded, and re-assmebled. Now it is hard as hell to start, even harder to keep running. Once she hits operating temp she runs without stalling/dieing, but the power just isnt there like befor. She doesnt like to shift into 2cd telling me she isnt hitting the rpm she use to. Again, Im thinking too rich, go to tweak her after a couple full runs, go 18th of a turn rich, no change, still smokes the same, still same lack of power and no shift. .... I go out another 1/8th..... no change... Now Im thinking, man how rich is 4 turns???...
So I thin it out by 1/8 of a turn......wont stay running, wont start and temps skyrocket....... let her cool... went back to 4 turns.... back to the same sluggish non-sence.
She had way more power during 6th tank on break in, what the hell happened?... is there a trick to tune the 2.5 after break in, or does it loose some of its pep once everything seats? Fuel is 20% and brand new. Airfilter is clean and oiled to spec.

rawkfist2

GO back to factory settings. HSN is 4 turns out and LSN is 2 i think. Someonje corect me.

MaxxRT

Try checking the LSN setting by doing the pinch test.

Meziked

Tryed the pinch test, getting about 3 sec of run time, so it should be good. And it is at factory settings at 4 turns out, still runs poorly and I have to do 2 or 3 laps at half throttel befor a can lay into it without it dying. From the amouth of smoke Id say she is way rich, but when i try to lean her out..... seems there is no medium and no increase in preformance....

Say your at 4 turns out.... how much do you guys lean things out? I guess i can try leaning out the low end and seeing if im flooding her down low.... but that wouldnt explain WOT beeing doggy....

DaveG55

Traxxas says 4 turns out on HSN and flush on LSN.
Just went thru the same thing. Go ahead and reset to factory and shove in a new plug. Break in can be real hard on glo plugs.
Not that yours will be any thing close to mine...but it seems to like about 3 3/4 turns out on the HSN and 1/16 - 1/8 in from flush on the LSN. Runs around 260 there with good wheelies and power.
Check all your lines, tank lid. use fresh fuel and start again Try not to get too frustrated, it never helpd.

MBX5T Maniac

My Feedback: (-1)

Take it easy on the engine for another 4 tanks. That's better on the engine. Leave it a little rich, and don't do WOT too much

Meziked

IM at 11 tanks already. Been tuning on it for awhile now. Looking into a big block, But as I understand it they are much harder to tune. Funny thing is, I can tune a 700cfm double pumper on a small block just by smell and sound, and get very very close to a correct a/f ratio on a meter. But this little bugger is a whole diffent animal. Im thinking a new plug would be a good idea, got a handfull of them just in case. Also thanks for the tunning tips, Good to know I have you guys to fall back on when I get into a situation that the book doesnt cover.

Meziked

BTW, I have ran her WOT sevral times, but only in spurts...... No rev limiter on a fuel powered engine... yeah I know the dangers... trust me. Iv sent a few rods south in my time, no proud of it, dont want to repeat.

89ram

i don't think that big blocks are neccesarily any harder to tune. some motors are better than others. i've had an axial.32 in a 3.3 revo for a while now, and just recently got a 2.5revo with an xtm 457[.28] in it. to me, they don't seem to be any harder to tune than my 3.3 was.

mrjerryk

This is where my HSN is. Start out with the 4 out and then lean it 2.25 turns in. If you think that might be to lean for you then try 2 in. Run a couple of laps to get her warmed up then check your temps. If its hot them richen it some. If it cool the lean it out. I don't rely on the smoke for the pipe to tell me that the motor is tuned right because different fuels have different affects on this. I tune with my temp gun and the sound of the motor.

You'll get it dialed in by trial and error.

89ram

i agree. i use a temp gun and listen, as well. i add sig castor oil to my fuel for added protection in case of a lean run. so there's more smoke then. leaves a really nice trail when you gas it, just like a chevy!!![sm=bananahead.gif][sm=biggrin.gif]

Meziked

Im running Blue thunder fuel, its the only thing my hobby shop has in 20%.
So your running 1 and 1/2 turns? wow.... And yeah, I was using a temp prob for the head, but i think a gun would be more reliable.
Plus the cool factor of a temp gun for around the house type stuff is worth the extra cash.

Also, I run this car till she is empty..... wait till cool while filling... check the filter and back to bashing.. anything worng with that or Am I running her too hard? Seems like if I have her set up correctly I should be able to run it all day without stops???

89ram

mez, i see no problems with your running all day when everything's tuned right. you'll probably want to check for loose fasteners a few times, with that much run time though.

Meziked

ok....now im starting to worry............
New glow plug, Medium temp traxxas long plug, still doing the same crap. Hard to start, Once started runs decent, then just dies. Then very hard to start. I have tried 4 turns out and the LSA flush with the grey sleave (about 2 turns out). I have leaned it and have richen it, will not stay running. Its weird, it runs good when it is running, if I give it over half throttel it bogs even when I ease into it. it dies like it is starved for fuel, I look at the clear lines and they are full. Traced my lines, top of the tank is going to the tuned pipe and the side is going to the carb. No visable gas leaking from the tank, so the pipe has to be moving the fuel. Im about ready to pull the tank and rebuild it....but man.....after 12 tanks of fuel and under a month???? seems thats a bit crappy. would the top seal leaking air do this? AM about ready to call traxxas tech support...... i cant seem to figure this out

McFly505

One gearhead to another.

BTDT.

OS LC3 glow plugs and new fuel line solved the problem.


Scott

Meziked

OK called tech support.... Dude was pretty cool. Explained what it was doing and what I have done, he said sounds like Im running way too rich. He wants me to pull the high speed into 3 1/4 turns and lean out the low by an 1/8th. Gonna try this and see what happens. I think I might be tuning it too quick, not waiting for the changes.... I was honest in telling him what i was doing and how offen, guesse I need to slow down....... will keep you guys posted...


BTW thanks for all the comments....

89ram

make sure to let the motor warm up first before adjusting, if possible. and take your time. small adjustments.

Meziked

ok nothing I did seemed to help, truck kept dieing. Sometimes she would hit low speed idel fine, other times she would just die like i shut off all fuel. I purged the lines by pulling the high speed needle and holding my finger over the exhaust while starting.... tons of fuel came out. Put her back together, went back to factory settings and she ran great for about 5 minutes then died and would not re-start. Waited for another battery to charge (about 5 minutes) and she fired right up and back to the same crappy preformance and bogging down even when easing into WOT. I set her up the way the guy said to, got her going again by priming the line although it was full of fuel, and it would not stay running. Man, i am doing something way wrong. When she runs, she runs well. I know im not too lean because how far out I have the needle. Seems she is loading up and dieing, but i cant lean her out without running into the no start problem. Im thinking the pressure system at this point. no fuel presure or non-consistant fuel presure causeing a rich to way lean then dead effect. I have been working on her for 4 hours now. pulled the engine. pulled the head and cleaned everything with nitro blaster. Then soaked everything in wd-40 and re assembled. Also replaced a bent dog bone and set tow-in. Added some beefer spings and long travel suspention. By the time it was finnished it was dark so i have not tried to re-test. Sleave looked great, piston showed some discoloration in the head, but not much at all. Gona leave the settings at 3 1/4 turn on the High and 1/8lean from stock on the low and see what happens tomorow. I have flushed all lines, cleaned the carb, tested the fuel tank for leaks and a clogged pickup...all were fine. Hopefully in my shotgun aproch to troubleshooting i have solved the issue. If not, be talking to traxxas tomorow aboiut sending it back to have them look it over. Hope they dont mind me painting it...LOL