newbie problems

[tricky1400]

hi i am new to nitro radio control and hope someome can help me with a problem i have with my BSD nitro assult buggy .

i have just run it in and have run it with another couple of tanks of fuel and everything was going great . . . then tried to start it over the weekend and it revved really fast making all four wheels rotate .

i first tried to slow the idle with the idle screw , as i turned the idle screw anti clockwise the engine started to slow down , but as i kept turning the idle screw the engine cut out .

the car wouldnt start again until i returned the idle screw clockwise again , it then started but was revving high again so started to turn the idle screw out again and the same thing happened , engine cut out again .

the car will start and run but only if it revs high and the wheels turn .

i know that when i apply the brakes the carb has to be open at least 1mm to allow the engine to run but if i put the brakes on or put the car on the ground the engine stops

the mixture screw has been turned in half a turn per tank full while running in as per instructions and its at 2 and a half turns now , i have tried increasing this to 3 and 3 and a half but it doesn't make any difference

would really appreciate some help with this

thanks

 

[Nitro Nerd]

Is the car new or used? Assuming the linkage and idle-stop is properly set (which is typically the main culprit in what you are describing), I'd say your LSN is too lean (it's idling high as it is starving for fuel). Richen it 1/8 - 1/4 turn and try it. Ideally you set your LSN first, then adjust the idle-stop....only if needed. If that does not fix it, check your clutch for a busted spring.

 

[tricky1400]

hi the car is new , only had it just over a week , as i said only just run it in , it worked perfect while running it in , idle was spot on , throttle response good after running it in , not really driven it hard or fast , i have not touched the linkage at all , i can see fuel spitting out of the exhaust when its running , what is my LSN ? and how/ where would i check for a busted clutch spring ? sorry i really am new to this , thanks

 

[BillyC74]

Use the idle screw to set your carb gap to 1mm, then use the lsn to control your idle speed. Richer lsn will slow down the idle.

---------- Post added at 2:19 PM ---------- Previous post was at 2:12 PM ----------

The lsn is on the side of the carb, near where the linkage hooks up.

 

[Nitro Nerd]

sorry i really am new to this , thanks

No worries, we'll get you up and going. With that--before going too much further, I would encourage you to take a little time to research "tuning nitro engines", as there is a lot great information on the Internet.

I say this out of experience, as when I first started, I jumped right in and did not research what to do - and ran into all sorts of issues. ;-) This will at least get you familiar with the needles, what they do, how to tell rich vs lean, etc. I'm sure you're still going to have a lot of questions (and probably issues afterward), but....it will get you a base understanding.

I believe there is a flow chart on this forum. Search for "tuning flowchart"...it's a great artifact!

 

[chickenman242]

check your engine clutch for a broken spring or bad clutch bell bearings,sounds to me like one of these is the culprit

 

[Alan81]

check your engine clutch for a broken spring or bad clutch bell bearings,sounds to me like one of these is the culprit

Do clutch springs stretch and wear out, or do they typically just break?

Sorry to thread hijack, just thought it was relevant to the topic, and I don't know the answer.

 

[Nitro Nerd]

Two shoe with single spring stretch and break, where invididual shoe springs snap, with the former being more likely, at least in my experience. I'd recommend replacing any 2-shoe.

Springs can wear, but it's most often from improper seating....OR taking them on/off a lot (as I do). Kind of like a screw. The more you take it off/put it back in the more it wears. However, I really enjoy optimizing my clutches so am constently trying new setups

 

[Alan81]

Two shoe with single spring stretch and break, where invididual shoe springs snap, with the former being more likely, at least in my experience. I'd recommend replacing any 2-shoe.

Springs can wear, but it's most often from improper seating....OR taking them on/off a lot (as I do). Kind of like a screw. The more you take it off/put it back in the more it wears. However, I really enjoy optimizing my clutches so am constently trying new setups

The reason I'm wondering is because I experience some wheel spin at idle, but it's not enough to get the car moving, only when I pick it up. Mine is a two shoe.

 

[Nitro Nerd]

Yeah, you have to get pretty creative to tune a two-shoe (drill holes to lighten them, rotate, etc.) Maybe in your case, ruling out engine/linkage, your spring might just be getting weak. If you get the chance to upgrade to 3+ shoe, it's like night and day. ;-)

 

[chickenman242]

@Alan81 if you want to stick to the cheap side of clutches I would suggest the mip replacement,sets you back around 15 bucks and springs can be purchased separately quite cheap
if money aint an object go for an m2c 36mm 3 shoe setup or a buku clutch but thems is expensive

 

[hamz9561]

Or a Werks Racing clutch is good but expensive as well.

 

[tricky1400]

clutch

thank you for all of your replies .

the car is less than a fortnight old and i have problems already !

i have a few questions to ask as your answers are confusing me :\

my carb ( slide one ) only has two screws , mixture and idle

when you say set your LSN what do you mean ?

also where and what do i look for when looking at the clutch , i am presuming
you mean the two spinning wheels either side of the throttle housing ?

how would i know if there was anything wrong / missing with the clutch

sorry to be a pain but i am a newbie

thanks again

ps is there a way to put photos on the treads , maybe this would help with your replies ? ! ?

 

[Jsmith]

Not to demean any of your questions. One thing here that is paramount to you enjoying rc nitro is a working knowledge of the system and it's applied theories. With that being said, I strongly urge you to take some time on you tube watching videos such as tuning, clutch inspection and so forth. There is a wealth of knowledge there that will give you endless amounts of knowledge in this hobby....AND IT'S FREE!! Please, don't get frustrated. It will come to you. Always remember that you can walk away from the rig for a spell. Fresh thinking is always paramount sometimes. Learn the basics first, then proceed. I wish you the best in this new learning experience!

 

[Cornholio]

I agree with what Jsmith just said. Before most of the videos were on you tube I learned almost everything I know from a book. The Ultimate Nitro Engine Guide For Radio Control Vehicles. . Probably the BEST book out there.

 

[Rolex]

On the top of this Nitro forum are numerous "Sticky" threads that are always on top. There's an encyclopedia of information compiled and contained in them.
Here's one dealing with tuning that includes most of the info you need.

https://www.rcnitrotalk.com/forum/showthread.php?t=60832

 

[Cornholio]

The reason I'm wondering is because I experience some wheel spin at idle, but it's not enough to get the car moving, only when I pick it up. Mine is a two shoe.

I was having the same issue until I tightened up my linkage just a hair, that took care of the wheel spin when I picked it up off the ground.

 

[tricky1400]

clutch

hi , took my car apart last night ( had trouble getting the engine out by undoing the screws at the bottom as they were rounded off , had to undo the engine from the top mounts ) .

and as suggested in your replies the clutch spring had broken , what stars you guys are , brilliant , i really like it when i take things apart and do find something wrong as it would have been really annoying if the spring had not been broke as that would mean looking for other faults .

next step is to buy a new clutch and spring and put it all back together , then fingers crossed all will be ok .

i will also be looking into maybe changing the clutch to the 3 shoe type at a later date if the 2 shoe one is going to brake that fast as i have put less than 10 tanks of fuel thru the car .

could i be doing something wrong to make it brake so quick ? or is this the norm with the 2 shoe clutch ?

thanks again for all your help and pointing me in the right direction , i wouldnt have found the problem so fast without your help .

thank you

 

[Alexander_0_1]

Ya, it is normal with 2shoe clutches cause the pads are heavier, and the spring aren't that much thicker than 3shoe clutches which are lighter (less mass). Also 3shoe clutches grab the clutch bell better.