Problem Savage

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Livewire

Livewire

***HPI TILL I DIE***
Messages
171
Location
England
My best mate has just bought a new Axial .32 for his savage (so he can try and keep up with me) but after the break in he has gone to tune it but it is stuttering when he is WOT, if you hold the truck off the ground and build up the throttle it seems to be fine!!!:dunno:

He has sealed the engine, and used a Integy 3 shoe alloy clutch and a 18 tooth Axial CB, 47 spur gear, also he has leaned the HSN out to make sure it isnt running rich so could it be the clutch not gripping?? here is a link to the YouTube video to watch the problem and hopefully point us in the right direction to the problem,

http://www.youtube.com/watch?v=ajQeTdrLSs4
 
Did you change out the glow plug after break in? It sounds like its loading up at WOT under load, and if the glow plug is not working properly it will not burn all the fuel. Also what are the temps where your at? Warmer=leaner,
 
is your pressure line on? + any exhaust leaks?

maby your engine is starved for fuel!!!
 
he did change the glow plug and the presure line is on, the exhaust is secured with the spring, it is using the hpi rubber part joining the manifold to the polished pipe and the ties are tight....using a cold hpi glow plug..
if it was still running rich it would stutter when in the air also wouldn't it??
 
What type of fuel are you using? You may want to try a hotter plug. IMO, the same symptoms may or may not be there whit the wheel off the ground. Wheels off the ground does not place a load on the engine.
 
Last edited by a moderator:
Check the mid range needle. I have owned several Axials and that needle likes to screw itself in all on its own.
 
Also, make sure your running a long plug with the Axial engines. They don't like short plugs. You will have high temps and a rough running engine
 
That almost positively sounds like a leaning issue. It sounds as if the motor isn't getting enough fuel, and the lack of a decent smoke trail at all shows that it's just not burning fuel. Personally I'd richen up the HSN and see if it fades out a little. If the effect is reduced, there's your answer. Trial and error my man, but here's some info to help ya!

I'm gonna list some thing to try to get that engine running right.

1 - New Glow plugs... Always have one just incase. A glow plug can cause so much trouble that it should be illegal lol.

2 - Factory Settings. Set those needles back to factory, start tuning again. Run it at stock first, get a good dose of fuel down the pipe and see how it runs at factory. Believe it or not, I've actually seen a Picco .21 from factory be set too lean for throttle. It's rare, but possible that the needles aren't nearly right. So take it to factory by the manual, and see what it does.

3 - Still problematic? Take the time to check the fuel. Check the fuel lines, tank, throttle assembly, all the bolts, the glow plug, even the exaust! Check, and recheck every possible problem. I've seen where an air leak in the manifold - Pipe sleeve caused an extremely rich engine, even when running at super lean settings! Check again, and again.

4 - Other tips? Tune in this order. HSN, LSN, then use the MSN to fine tune the rest. Only tune in that order. If you need to make adjustments from factory to start it, then go from there. Finding the right tune can be a long and time consuming process but is worth it, trust me.

5 - Other things to look at? Try a different plug type, or different fuel. My TRX .15 pro literally hates trinity monster brew, and run Odonells racing blend like a champ. Probably mainly due to the oil content, but it's worth looking at. Also, the TRX runs better with an OS plug then it does with the stock McCoy in it. Plug temps are also a big factor. Remember this as well.

Warm temps, run a cold plug
Cold temps, run a warm plug

A couple other things to remember. These engines wear over time, and with this wear comes the need for retuning. I retune my mills every time I run them. Every degree in temperature, and even a foot in elevation causes ever so slight changes in air intake. Running the right tune for the environment your in is key! On a 90 degree day, you might run 1.2 turns in, and on a 50 degree day you might have to run 0.5 turns in. It all depends on the environment you are in!

Another good idea to look at, air filters.. I can't remember how many times I've seen people have problems with their engines be a result of the air filter. Most of the time, it's just an ignorantly filthy filter, but that's not always the case! Some people just don't know when to stop with the air filter oil either. HPI's instructions should be avoided as well. One capful of oil can mean anything. I've seen some giant caps on air filter oil before. You should just go with about 20 drops and work it into the base filter. Then put about half of that into the outer filter. This way, the oil isn't constricting the airflow either.

Remember, these engines are incredibly simple, air and fuel. Just look at how they work and try to understand what makes them tick. Once you realize the method they use, it's easy to recognize problems from there. :)

I hope this helps you out bud. Let us know what happens.
 
AoD said:
That almost positively sounds like a leaning issue. It sounds as if the motor isn't getting enough fuel, and the lack of a decent smoke trail at all shows that it's just not burning fuel. Personally I'd richen up the HSN and see if it fades out a little. If the effect is reduced, there's your answer. Trial and error my man, but here's some info to help ya!

I'm gonna list some thing to try to get that engine running right.

1 - New Glow plugs... Always have one just incase. A glow plug can cause so much trouble that it should be illegal lol.

2 - Factory Settings. Set those needles back to factory, start tuning again. Run it at stock first, get a good dose of fuel down the pipe and see how it runs at factory. Believe it or not, I've actually seen a Picco .21 from factory be set too lean for throttle. It's rare, but possible that the needles aren't nearly right. So take it to factory by the manual, and see what it does.

3 - Still problematic? Take the time to check the fuel. Check the fuel lines, tank, throttle assembly, all the bolts, the glow plug, even the exaust! Check, and recheck every possible problem. I've seen where an air leak in the manifold - Pipe sleeve caused an extremely rich engine, even when running at super lean settings! Check again, and again.

4 - Other tips? Tune in this order. HSN, LSN, then use the MSN to fine tune the rest. Only tune in that order. If you need to make adjustments from factory to start it, then go from there. Finding the right tune can be a long and time consuming process but is worth it, trust me.

5 - Other things to look at? Try a different plug type, or different fuel. My TRX .15 pro literally hates trinity monster brew, and run Odonells racing blend like a champ. Probably mainly due to the oil content, but it's worth looking at. Also, the TRX runs better with an OS plug then it does with the stock McCoy in it. Plug temps are also a big factor. Remember this as well.

Warm temps, run a cold plug
Cold temps, run a warm plug

A couple other things to remember. These engines wear over time, and with this wear comes the need for retuning. I retune my mills every time I run them. Every degree in temperature, and even a foot in elevation causes ever so slight changes in air intake. Running the right tune for the environment your in is key! On a 90 degree day, you might run 1.2 turns in, and on a 50 degree day you might have to run 0.5 turns in. It all depends on the environment you are in!

Another good idea to look at, air filters.. I can't remember how many times I've seen people have problems with their engines be a result of the air filter. Most of the time, it's just an ignorantly filthy filter, but that's not always the case! Some people just don't know when to stop with the air filter oil either. HPI's instructions should be avoided as well. One capful of oil can mean anything. I've seen some giant caps on air filter oil before. You should just go with about 20 drops and work it into the base filter. Then put about half of that into the outer filter. This way, the oil isn't constricting the airflow either.

Remember, these engines are incredibly simple, air and fuel. Just look at how they work and try to understand what makes them tick. Once you realize the method they use, it's easy to recognize problems from there. :)

I hope this helps you out bud. Let us know what happens.
Click to expand...

Been out with it again today, checked everything over all seems to be set up right, changed the glow plug for a new one, put back to factory settings and tuned slowly starting with the HSN, got it to the point that it does pull ok but does still stutter every now and again, it still wont run perfect and if the settings are changed even a 1/8 of a turn (from where we have it going the best) on eaither the HSN or LSN the problem gets worse??? We even turned the mid range needle 1/8 each way (for 30 seconds of running to see if that would help) but this also made the problem worse. (so put the mid range back to factory setting) Its now at the point when it will accelerate up to full speed but does stutter half way through and then goes ok up to full speed!!

We are using Byrons 25% fuel, will be trying a different brand of fuel next to see if the fuel is the problem...but the Byrons is great in my Axial .32 so I don't think it is the fuel....

I might just run over it with my 1/1 car, that would solve the problem!!!
 
Have you taken the needles out and looked to see if all the O rings are ok? Also the carb O ring can get damaged when you turn the carb around.
 
The carb has been sealed, but didnt seal the needles because we cant find the green slime anywhere, is there anything else we could use to seal the needles??
 
Do not touch the mid range needle ......!!!!!!!!!!!
 
Also, I've actually resulted to using diff oils before. It seems some really thick, 70,000 or so weight diff oils work well. AE Green Slime is good, but sometimes hard to find.

Using 1/8th turns is good to get in the range you need to be in. After you find the best spot, start tuning very lightly. If it's not stalling out on initial take-off, or idle then the low end isn't going to cause too much trouble for you.

Take the high end, and VERY lightly turn it lean or richer until you find that perfect spot! :) Don't give up however, you'll get it eventually. Like I said before, it's all trial and error with tuning a new mill :)
 
AllanQ said:
I used vasoline to seal my o-rings. Have not had a problem yet.
Click to expand...

thanks for that, I will use some vasoline on the needles after I finish work today. should I do the mid range needle also or just cover it with sealer??
 
Personally I would not use or recommend vasoline, as it is petroleum based and does't agree with some O rings. I would stick to a silicone grease or even as AoD suggested, just use a tiny amount of the thickest diff oil you have. JMO.
 
Loctite the threads and seal the crap out of the MRN. I do it to all my Axials. Less headaches in the long run.
 
oregonmud said:
Loctite the threads and seal the crap out of the MRN. I do it to all my Axials. Less headaches in the long run.
Click to expand...

does the MRN come right out?? I a bit worried about messing with it...
 
bit of an update, been cleaning both our savages today, (its raining like crazy in the UK at the moment so cant take them out to test) but I have noticed that the fuel line he is using is quite a bit narrower than the fuel line I am using.. he bought some fancy light blue fuel line from the LHS but I think they sold him fuel line for use with smaller engines!! :duh:

Could this be what is causing the problem? we will change the fuel line and go test as soon as the rain stops.....thanks for all the advice so far I don't think we would get by wothout this forum..:resp:
 
jcam54 said:
fuel restiction can cause that such as a dirty fuel filter or too small fuel line...basically it half starves the motor.
Click to expand...

All sorted now, changed the fuel line and that sorted the problem!! also we had changed fuel from 20% to 25% and let the truck idle through 2 tanks to get the engine used to the 25% and now it is running fine!!! not pulling wheelies yet but I'm sure it will come......THANKS everyone for all the help provided, received my BUKU yesterday :jamout: :hellfighter:
 
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