ok, i will try and sum this up . it has become rather annoying as this is the vehicle i want to race of my 3 more then the others.

ok, a hyper 7 running a picco 21 8 port (no pull start)
this engine rocks. fast as can be, extreme low running temps.

when running it is amazingly fast top and low end.

the issue i aving is that it continues to die out on me.

i have switched plugs, checked fuel line. i thought for awhile the fly wheel might be bumping when landing from a jump. now i think maybe due to a dirty air filter?

seems to occur mostly when hitting full throttle for a second or two then cuts out.

idles amazingly. preforms great but just can not figure out a way to make this stay running around the track. just started doing this recently.


i would love any feedback and brainstorming to help me figure this out as i am very stumped at the moment.

thanks

Check to make sure your gas tank isn't leaking air. I had this problem with my rc10 it would idle fine take off and then bog out and die at full throttle. I found it to be leaking air at the fitting that goes out to the carb.

i will triple check for air leaks.
luckily i have a second tank sitting around.

what are the odds that a dirty air filter could cause that effect?

seems like it would not be that cuz my other buggy has run much dirtier and never had that issue.

thanks again, at least one of ya tried to help me brainstorm, lol

The air filter could be although it sound stange to give you so much problems. When you say the engine dies how does it do it exactly. At idle after a while, at full throttle?
If it is the air filter is too dirty everything should be running too rich which means less power than usual maybe dying if it is way too rich due to the filter.
Checking is easy. Go somewhere that is relatively clean (no mud or anything similar close) and start the engine without the filter. If it is ok then it is the filter, if not it is something else. I know it is not the most elegant way but if you want to know NOW I guess this is the only way. Otherwise just buy a new filter or clean this one.

i'll try cleaning the filter, i have my doubts that is it, maybe change out all the tubing, i am not seeing any air in the line though so i am doubting if it is an air leak then it is more then likely not in the tubing.

Sounds like a fuel problem or possibly overheating.

What are your temps?
Possibly overheating?
Does the engine start right back up after it quits or does it take a little while before it starts again?

Have you flushed the carb...Possible debris in the line or carb.


Dbow

this engines runs so cool at such high preformance, anywhere from 180-220 is the standard i am getting depending how lean i get it.

you would be amazed at the speed it has at those low temps.

so it's not a heat issue.

i thought maybe i was bumbing flywheel till i it on flat ground testing it and got the same issue.

it is much worse when cold but continues at heated temps as well.

i have not flushed the carb? please explain that to me.
thanks.

Flushing the carb just means to clean it out. Sometimes debris can get caught up in there and wont cause a problem until full throttle.

I take my needles out and clean and flush them out with cleaner or nitro.

This may not be the problem in your case just a suggestion though.

Dbow

I am thinking of two things.

First, are you sure your temp gauge is accurate. Because you could be lean and don't know it.

Second, perhaps you are using too cold of a plug to run with those low temps you are getting.

I run OS A5 plugs, but I keep an idle of 240 in my ofna force .25 .

my force 25 is about 250 also, my force 26 is around 245

my ss25 is about 260

my picco 21 is about 200-220

wish it was to lean but it pours out a nice poof of smoke as it blows everything away.

my temp gauge is working great gets the same readings as everyone else.

hmmm. ok, so far i am still thinking maybe that the carb itself might be an air leak or the back plate but to be honest i am not sure if cutting out this way would be the symptom of that or not?

I had a problem of my engine cutting out at first, but the method was slightly different...

Basically, the engine would run for 10-15 seconds then cut out.

I narrowed the problem down to an air-leak in the exhaust, so there wasn't enough backpressure to pump fuel into the engine. Maybe yours is a less severe case of the same problem, whereby when you need more fuel there isn't enough pressure to supply it?

I'd check that all your exhaust bits and bobs are on tight and undamaged...

Sorry if this seems dumb, but I'm still learning ya know :P

that sounds like a possible answer, i am leaving town for 10 days and when i get back i am going to redo and check for any possible air leaks 1st.

if the engine would stay going then this buggy would be great for racing, better then my other 2 nitros for sure.

although the sav SS almost seems more fun.

Well, gimme a week and I should be able to tell you

Hopefully it'll solve your problem - I can't believe I was actually helpful

I ended up just stripping the exhaust manifold off the engine and giving everything an extra good clean, then sticking an extra tie-wrap on all the rubber seals. Seemed to do the trick OK - I've not had any unexpected stalls since

Except for when my fuel tank cracked - hell people, if you think that cars running uneconomically, ffs check the fuel tank

It took a huge puddle of nitro on the road and only ten seconds running from a full tank for me to clock on

Damned LHS having to order in parts. Grrrrrrr. I wanna run my car again!

*rant mode disabled*

*sleep mode enabled*

Nanite peeps, and don't forget to tell us how things went when you get back Shozz - PM me if the thread's dead

i have a one piece ofna pipe and just remmebered where it fits together on the pipe side is not perfectly flush, there might be a gap there, would that create this issue?

I'd guess it might...

Try getting a little grease / silicone in the joint to try and prevent air leaks, and throw an extra tie-wrap on to hold it in place a little tighter...

Hope it works

one piece pips are help by springs.

i will check that area 1st before sealing the carb and backplate.




is an air leak actually somethinb that will make a car die when you hit the throttle but not effect it whatsoever when you are at idle?

Well, I can't say it'd definately apply to rc, but my best guess says it could...

Basically, if there's the tinyest of gaps it might not open up to the point where air can escape until the pressure inside is significantly higher than atmospheric pressure, such as when you open up the throttle.

If you're not sure what I'm getting at, lemme know and I'll try and explain it a bit better. My head's still stuck in programming world atm, damned clients keeping me away from RC

yes, when at idle the pressure is not that great but when you "punch it" you are building a vaccum which will allow in more air which will chock your engine

allright now this is sounding a lot like it might be the case. i have to go catch a plain to L.A. will be at KZ speedway this monday if any of you are around that area.

anyway when i get back on the 27th i am going to fix the pipe and seal the carb/backplate and will post in and let you know if that fixes it.

keeping my fingers crossed.

Keepin' ours crossed for ya too bud

Smokinjoe6450: You've got the other end of the stick I'm holding there mate - the pressure that builds up in the exhaust is pumped back into the fuel tank (as well as out the exhaust) to help push in more fuel isn't it? I'm thinking if there's a leak in the exhaust (albeit a minor one, not noticeable at idle / low speeds) then there isn't enough pressure to give the engine enough fuel when it reaches the higher RPMs...

well this sucks and i assume this is the main issue.

i take of the air filter and the shoulder hose, and walla, there is a pile of mud which is mud due to fuel caked around the inlet.

i can only imagine that the engine is completely blown .

the filter was not even very dirty.

aggghhhhhh

yack!!! that happened to me and i had to replace the piston//sleeve in my cheapie TA18 Take apart the engine and give it a good cleaning, piston sleeve and all, then put it back together and see how it runs. If it can't handle a couple tanks w/o dying half way through a single one, or becomes very hard to start, the engine is probably ruined never hurts to check though!

strange thing is i can idle through an entire tank no problems as well as run 1/3 throttle through it.

samething happened to me man, i couldnt figure out what it was!! i thought i had a massive air leak too. It ran strong till half way through, it'd lose all power, over heat drastically, then cut out. After trying everything in finally tore the ******* down and found globs of dirt.