Hi, I have a Tornado BB with the .18 thats giving me issues. There is a lean-out that develops at mid-throttle. It will putt around fine until I get into the gas and it leans out. Ive checked the tank and there are no bubbles going to the carb. I removed the carb and sealed it where it meets the case and all around the carb with high-temp red. The pull-start back plate is dry as a bone and doesnt look like it is pulling air. My high speed needle is set at 2 turns out and I experimented with richening it up to as far as 3.5 turns out and the lean condition persists. The low speed needle is even with the silver collar and I slapped a little high temp red over it just in case. Am I not getting enough backpressure? Im running out of ideas...

there have some issues with them not getting enough gas because the intake in the gas tank is partially blocked with plastic from when it was formed. Just a thought.

you say its leaning but what is the actual problem you are having? Is it overheating?

No overheating, just a lean bog about halfway through spooling up. If I let off the gas, its fine. If I continue to gas it, the engine will cut out.

ehroof should know we dont get this probelm verry often

Anybody else want to chime in?

ehroof still at work now sorry hel be on later

I'm with Dennis, I would check the fuel line nipple I've had few that have this odd lean condition because of there ended up being a small sliver of plastic that got pushed in behind the nipple when they screwed the nipple in to the tank. Fuel still flowed through the fuel line everything looked normal, but it realy wasn't there wasn't enough fuel moving fast enough through the line. Another thing could possibly be that it's running way to rich still and it's not actually bogging out from being lean it's bogging out from too much fuel, you said ti wasn't over heating so what is the temp near?

Well, when I richen it up, it runs better but takes a bit longer to bog out. when I lean it out it bogs even quicker so Im positive its a lean bog. This is all from adjusting the needle from 1.5 to 2 turns out.
Im going to pull the tank and put the other one on from my shockwave and we will see if that solves it.

That's what I would do then, is pull the tank from a working car.

yeah does sound like a leak somewhere. If you take the pressure nipple off the pipe can you blow the fuel through easily or not?

Yes I can. there doesnt seem to be any resistance. I took off the nipple and there are not any burrs in the plastic.

hmm...when it suffers from these lean bogs, does it cut out completely or splutter? Do you know what temp the engine is running at? When you tried richening it up, did you do it in small increments and give the engine a few minutes in between each adjustment? It can take some time for needle adjustments to take effect.
Asked this before but have you looked for possible leaks in the lines, tank a pipe? Sounds like you could be loosing pressure perhaps?

Its definately a lean condition. Theres no sputtering. Ever owned a dirtbike or fourwheeler or even a go-kart? Its the same symptom as when a dirt bike runs out of gas....kind of like a "boggg, boggggggg, boooogggggggg"....and then shuts off, unless I let go of the throttle, then its fine. It will idle forever, the pinch test yields about 2 1/2 seconds before shutting off and temps are around 210. I cant really warm it up to normal operating temps cause I cant run it faster than 1/4 throttle. I replaced the lines w/o any difference. I even swapped a carb that I know is working from the shockwave and no change. Also, I took the pipe apart and visually inspected the pressure nipple from the inside...its fine.

thats telling me your LSN is running too lean and needs richening. If you have been richening the HSN then wouldn;t really help the situation. With the pinch test the idle should increase sharply and then take about 5 secs to quit. 2.5 secs is a little too fast and the LSN is most likely whats causing the lean bog at less than qtr speed.

Im going to richen up the LSN when I get home and report back.
I always thought that 5 seconds was a little too rich. I always aim for 2 1/2 to 3ish for the pinch...maybe ive been wrong this whole time.

Well I put the new tank on, no change...
I richened up the LSN, still bogs at mid throttle...
richened up the HSN and it fixes the problem a little bit but its so rich that it wont even shift second.
Im almost at sea level and theres no reason I should have to run this engine richer than whats recommended for BREAK-IN if its not got some other problem.
I pulled the head, the piston looks fine... Im not sure what to do about this.

I had a similar issue earlier with my monster gt. I ended up slightly leaning out the low speed and richening the hi speed needle.

When you say mid-throttle, do you mean mid-rpm? for me it's either idle-throttle or HOLYMOLY-throttle

Seriously now, what percentage nitro are you running? perhaps your plug is not really suited for that percentage nitro at high-rpm, so you have to lean it out to get acceptable high-rpm, sacrificing your mid-rpm? I dunno much about this really, I'm just throwing ideas out there. Perhaps try a plug one step hotter or one step colder and see if that helps.

yeah every engine's different hey put if it cuts out within a couple of seconds its usually a little lean on the LSN. Geez this is an odd problem hey. I still think its a tuning issue but I could be wrong. You say you wont shift into 2nd, could it be clutch related?
By the way how old is the engine? Is it run in? Or have you not got that far yet?

Whats really confusing is that this condition manifested itself rather quickly. The engine ran fine after break-in for a few days and then I noticed the temp started to climb slowly during the run so I richened it up progressively but it began to lack power due to the rich tune. Thats when I set it back to 1.5 turns out from bottom and thats when the lean-bog began. The nitro is blue thunder sport 20%.

To further confuse things, I have the Tornado and the shockwave. The .16 on the shockwave is set to 1.5 turns out and the LSN is even with the collar and it runs liked a champ. why would the .18 on the Tornado require such rich settings to operate if there was not an underlying issue?

Just a dumb question........How old is the fuel your using?[:-]

try replacing the carb, redcat danny and i were running one day and we just couldnt get his carb to tune no matter what we did, kept cutting out, i had a spare carb from an os .12 cz and it fit and worked great, he hasnt had a problem since them.