Diagnostic time (again) :(

[RC Addict]

Keep in mind that, if you do have an air leak in the fuel system (anywhere from the tank to the fuel lines), you will see air gaps in the fuel line. If you have a steady stream of fuel going to the motor then you don't have an air leak in the fuel system itself.

Other than that, I wouldn't think a rich HSN would do much to the tune down low. The HSN tends to kick in somewhere above 20% throttle. Just off throttle like in your video suggests a nice (and pretty spot on) rich setting on the LSN. That is why I (we) are sitting here scratching our heads...

 

[Mickstix]

Yea, the fuel line stays full of fuel.. I'm right there with ya as far as the head scratching goes.. Maybe the carb is whacked? When I was sealing up the engine I checked out the carb needles and stuff, looking for a buggered up needle or something fishy, but it all looked fine.. Anyway, hopefully the tune will come around.. All I can do is keep feeding it fuel and richening the LSN as I go.. When I first got it, it did fine for the first 3 or 4 tanks of breakin.. Then my glow ignitor crapped out, and I thought it was the needle settings that wouldnt let it start, so I got them all out of whack (w/o first noting the turns from factory) so I had to rely on an old manual for the stock settings (3 turns out of both, and 1mm idle gap) and that got it to start, but ever since it's not been right and I've been chasing the tune.. The tune doesn't change by itself though, but it just doesn't allow me to lean out the LSN like it should, w/o dieing immediately on throttle.. But I do thank all of ya'll for the diagnosis and help!! I was just happy to have the thing run for a whole tank of fuel, w/o having to restart it over and over.. It was the weird (horn sound) noise that was freakin me out.. I'll keep messing with it and hope for the best! (once it warms up again.. I was lucky that it got up to 60 the other day so I could make the video.. Supposed to only get up to the 50's for the next week.)

 

[MotoGod]

Well remember the HSN also regulates OVERALL fuel delivery. So while it doesn't have a huge affect on the LSN, it DOES affect it. So if your HSN is overly rich, you would have to over lean the LSN to compensate for it.

What I would do personally.....is set the LSN to a spot where the truck runs, and assuming the engine is broken in do some wide open high speed passes down the street or track. Get the HSN tuned to where you get a good smoke trail and no bogging...as well as good temps and then adjust the LSN from there. Most tuning guides have you setup your HSN first, and then the LSN since the HSN regulates overall fuel delivery. If you set the LSN first and then the HSN...your LSN will be out of whack again.

It's worth a shot, especially if you have already sealed up the engine.

 

[Mickstix]

I'll give that a try as soon as it's broken in.. It's only had about 6 tanks (900 cc) of fuel run through it..

 

[MotoGod]

Oh well in that case...just keep it running and drive it ;-) Hard to tune when mechanical pinch is in the way anyway. Keep that sucker heated up...

 

[Mickstix]

Yep.. I'm up to runnin it a tank at a time at 210 - 220*..

 

[Scrogg]

Pulll the HSN housing back off, clean everything. Pull the carb to WOT, screw the LSN all the way in. Then back it out 2 1/2 turns.
Take that fuel tank and submerge it in the kitchen sink. Leave the fuel and pressure lines on it. Put a screw or in the fuel line end to plug it off. Blow into the pressure line while the fuel tank is underwater. If you see any air bubbles, you know what to do.
I still have not watched the vid, I will tonight hopefully. My work blocks all vids.

 

[2revo1maxx]

It sounds very lean on the lsn.

 

[Scrogg]

Richen the LSN, it's too lean.
What brand of fuel, what Nitro and oil % does it have?
What glow plugs and pipe are you using?

 

[Mickstix]

hehe.. I've posted this numberous times, but I KNOW the LSN is too lean.. It just wont run if I start richening it up.. Like I said before, any more than a 1/12 turn (richer) at a time and it'll die as soon as I give it any throttle. (And once I give it that 1/12 of a turn, I have to run it for quite a while before I can richen it again, else it dies and I have to start over by leaning it 1/2 a turn again (that's not a typo.. If I richen it 1/12 of a turn too much, it'll die and I have to lean it a HALF turn before it'll run right again. Then I can start over richening it 1/12 at a time) I also tried closing the idle gap some more today, thinkin I might of been imagining the 1mm gap, but when I close it ANY more, it barely starts, and only idles for about 10 seconds and dies.. So I put it back where it was.. But the good news is, I ran another tank through it today, and at the end it was running pretty good, all but for the idle still being too high. When I was done I checked the needles, to see where I was at.. The LSN was 2 3/4 out (Only 1/4 turn to the lean side, from stock, where as when I first started it would'nt run at all unless I was 3/4 of a turn lean) So, it's getting there, slowly but surely.. The HSN was 2 1/4 out, which puts it at 3/4 of a turn lean, from stock.. If I richen the HSN it bogs at anything more than 1/4 throttle, which I dont mind at the moment, but it also doesn't get above 200* like that so I leaned it out to get it to run at all throttle levels.. It ran good like that, but it's idle is still too high.. From the needle settings it appears it's running like it should, for the needles being lean.. Only prob is, it wont run (yet) if I richen them up to where they should be.. Granted, I can richen the LSN and get it to idle fine while its running, but as soon as I try to introduce any throttle, it dies and wont restart until I lean it back out.. But I'm still hoping in a few more days it'll be ok? We'll see.. I'm up to about 1000-1500 cc's of fuel through it so far.. Thanks again for the help!

Scrogg: I'm running 20% traxxas fuel, stock SH pipe and medium SH glow plug (stock plug is also an SH medium)

 

[2revo1maxx]

It does sound like a mystery no doubt. Maybe the idle is set too low and if you set it higher you can richen the lsn at that point. Just trying to help, might be worth a shot.

 

[olds97_lss]

Just curious, have you checked your head bolts? Might not hurt to pull the head and button (if it's a two piece) and make sure you have a shim in there. Then tighten it in a star pattern to make sure it's nice and even.

I've received brand new engines with loose head and back plate screws before. I read that you "sealed your engine", so I"m assuming your talking about the back plate. But that doesn't require a person to touch the head bolts.

I have to say though, I've gotten a few engines that were new that if they were my first engine into the hobby... I may have just gone electric! Some of these silly things sure can try a persons patience.

 

[Mickstix]

Revo, that is definitely worth a shot.. I'll try anything at this point, cause before long its gonna be fully broken in, then my patience is going to start getting thin.. But I'll give it try tomorrow if the temp gets above 50*... Dang winter just showed up in Fl. and wont go away..

Olds, I did have the head off when I was sealing the motor.. I like to inspect everything, and it does (did) have a shim between the block and head button.. I also rechecked the bolts after the first few days, but havent done so in a while, so I'll give them a check tomorrow, and pull it off and make sure the shim is on there as well.. I was thinking, it's weird when I first start the engine at the begenning of the day, it'll start and idle fine.. But while I'm letting it warm up, the idle just starts rising, until it finally tops out.. But it'll idle fine for about 10-15 seconds, then I guess as the motor warms up it starts looseing up, and by the 25-30 second mark it's trying to pull the car along with the idle.. I dont know if thats strange or not, but I dont recall the idle on my buggy (small block .18 SH) ever doing that.. It would start and hold the same idle speed for as long as I let it set there..

 

[RC Addict]

See, the fact that it starts fine and then starts revving up just screams air leak of some sort somewhere in there. All I can say is "Good luck, bro"!

 

[Mickstix]

I guess I could tear it back open and reseal it? Aint like there's much too it. lol.. I checked it over this evening after running it, looking for some fuel or something leaking, but it's dry all over.. It's a major pain in arse taking the motor out though.. The 4 screws that hold it to the chassis must be welded in.. I had to take it out by removing the motor mount screws last time. (the ones on top) and with the spacers and blind lock nuts inside the motor mount, it's a chore getting everything lined up and back together.. I even tried holding a hobby torch on the screw heads, and they still wouldnt budge.. But when alls said and done, if it's still not acting right, I'll have to try resealing it..

 

[RC Addict]

Ah, LocTite. Both friend and foe!

Oh, and if I may--Ditch the Traxxas fuel and go with Sidewinder 20% (my fave is Race Blend w/ 16% oil) or O'Donnell's 20%.

 

[Mickstix]

I'll see what they have next time I'm at the LHS.. They had something that was red/pink but I can't remember what it was off the top of my head.. I'll check it out though.. Ya know, you got me to thinking about an air leak.. Remember I said I had run it through 4 or 5 tanks of fuel, doing the "old fashioned" breakin method.. Well it ran fine during that.. Then it turned cold outside, and I didnt run it for a couple weeks.. In the meantime I opened the motor and sealed it up.. When the weather warmed up and I got back to breaking it in, I had problems getting it started and got the needles all out of whack (turned out to be the glow ignitor) but anyway, I always figured my problems were from the needles being messed up, then not knowing what the stock settings were.. But now that I think about it, sealing it up could of been the culprit as well? I dont know how I could of introduced an air leak while sealing it up, but anything is possible.. If it turns out to be an air leak I'm gonna have to find a new forum to post on cause I'll be too embarrassed to stay here..

 

[RC Addict]

Sidewinder is reddish/pink, and is a product I stand by and run in all my nitro rigs. Fear not, you find and fix your problem and I promise no one will give ya flack. If they do they will be dealing with the rath of RCA!

 

[MotoGod]

If embarrassment chased people away from the forums...there would no users here my friend! We have ALL embarrassed ourselves at least a few times. I remember my first set of posts about getting a Duratrax Warhead started. It just would not fire up. The ultimate problem? I was using a Drill to power my RotoStart, and the drill didn't friggin spin fast enough! Talk about feeling like a nub....

As far as fuel goes, Sidewinder is great...Byron's is great...O'Donnell is great...and some guys hate it some guys love it...but Torco is an up and comer in the RC Fuel market as well. From what I hear, Traxxas is junk fuel though...but I have never run it myself.

 

[hamz9561]

I used Sidewinder's Kool Power (a heli fuel) in my Revo with no problems at all.