tcv_racing

I ran my Firestorm today and at top speed during WOT it bogs, but it seems that the HSN is still rich because there is still thick smoke coming out and nitro drips out the pipe when its idling and the body is covered with nitro(or oil) on the left side..The HSN position is 1/2 to the left from factory set.. Thinking that it was too lean thats why it was bogging I richen the HSN 1/8 turn and the bog was gone(or so I tought)..

-What do you guys think? Should I lean it out more?
-Do you think my engine is busted because of wrong break-in? (My storm is only 2weeks old)
-What is a "RICH BOG"? Is that what im having?

Thank you in advance!

C.rusak

i think you should try leaning it out. I use ti have problems like that when i started into the hobby, but if you mess with the needle, you will be a pro tuner in no time.

rclynx

An engine won't bog at WOT very often from being to rich and the oil out the exhaust at idle are totally different issues [&o]

kweezinarts

try leaning it 1/8 turn and check for performance gain, continue and lean until low smoke then turn back 1/8. if you want to be easier on the engine turn back another 1/8...

should have good performance without being to lean...

do you have the lsn set right?

to check try the "pinch."

take it on a high speed pass and get the engine warmed up. then bring it in and pinch the fuel line to cut the engine. if it revs up high before turning off, its too lean. keep doing this until you get it to turn off without revving up much. and you should be able to idle without the throttle trim turned up...

hope this helps...

dviga001

Had this exact same problem with mine, got it about 3 weeks ago.

Lean out the HSN slowly until it does not bog down anymore. make sure there is still a little bit of smoke coming out, and then go down and tighten the LSN about 1/8-1/4 turn.

Mine runs like a champ now

oooh, also make sure it is warmed up before running and tuning. I think this may have helped with it as well

tcv_racing

Thanks so much for all the replies!!!

Ill try re-tuning it again on my day off, give it more turns towards the lean side and hope it fixes the bog..

RCtruckRacer

More often than not, when an engine bogs at high RPM's its because the tune is too lean. This always works for me:

Why do we ‘tune’ our engines? How is it done? This guide assumes that you are familiar with all of the parts of your R/C's engine. If you are unsure what a Low Speed Needle (LSN), High Speed Needle (HSN), idle screw etc are, please refer to the manual (RTFM).
Tuning a nitro/methanol 2 stroke engine literally means adjusting the air/fuel mixture inside the chamber. This is done by means of adjusting the amount of fuel that is allowed to flow into the carburetor via needles which can be opened and closed. Most of us know that there are a wide variety of factors that affect that air/fuel mixture in the chamber other than just adjusting the needles. Because of this an engine may have to be tuned several times in the same day for optimum performance. Not maintaining an optimum air/fuel ratio can result in poor performance, or even engine failure!

There is a point, in every engine, at which air/fuel mixture will allow the engine to obtain its maximum HP and RPM’s. Tuning your engine to that point can be dangerous, as the mixture is somewhat lacking in the lubricants necessary to give maximum protection to the engine. Therefore, most people will want to run slightly rich (more fuel in the mixture) of that point. This is referred to as the ‘Sweet Spot.’ Some racers will run at pure max potential, but they also don’t usually care if the engine only lasts a gallon… Running at those settings can be very dangerous because being too lean is just a very slight adjustment away.

And running lean is the real engine killer, not temperature. With proper lubrication, the internal components of an R/C engine can easily withstand temperatures of 300F, maybe even more. The thing is, these engines are designed to operate at temperatures around 210 – 270 F. While there is the possibility you will encounter an engine and conditions that dictate the temperature at proper tune is over 300, it will be a rare occurrence. What that boils down to is that there is a good possibility that there is a problem if your engine reaches too high of a temperature. That is why it’s a good idea to monitor the engine temperature, but not use it as a guide for adjusting the air/fuel mixture in the engine.

So, how do you get to that ‘Sweet Spot?’
1) Start out with rich settings. If you are unsure how to go about this, an easy way is to start with stock needle settings. This includes the idle screw - make sure it is set at factory settings, usually a 1 or 2 mm opening for the idle stop. The factories always set engines rich for break ins.
2) next, warm up the engine. Try not to hammer the throttle too much while its still bone cold, but slowly work your way up to a couple WOT runs.
3) Now that the engine is warmed up (1/2 tank is good), do a couple WOT runs of about 50-100ft in front of you and pay attention to the pitch of your engine. The higher the pitch, the more RPM's its doing.
4) Now lean out the HSN by 1 hour increments (30 degrees, 1/12 of a full circle etc) and continue to do some WOT runs in front of you. The engine's max RPM's should continue to go up each and every time you lean out the HSN by those 1 hour changes. If it doesn't, you have reached the top end and need to richen by an hour. Make sure that you do not continue to lean out the HSN after max RPM's have been reached. You will damage the engine.

Congratulations, you just found the sweet spot. Now, if you notice that the car/truck bogs a bit at take off, lean out the LSN (again 1 hr increments) until it will take off at the touch of the trigger. Keep in mind that any needle changes won’t take effect immediately – do a couple of long runs (50-100 feet or so) to make sure the air/fuel mixture has corrected to the current needle settings.
And you're done. At this point I like to temp the engine to get a baseline r

Argess

Really nice instructions RCTruckRacer. That should help him fix it.

Ignore the following TCV, it is for RCTruckRacer:

Only thing I found that is different is that I usually find a high RPM bog (at WOT) to be rich. If I get the HSN too lean, I don't get a WOT bog, I get a WOT flame-out. The more I think about it, I'm not sure I ever get a WOT bog.....usually a "bog" means hesitation, or slowing down, upon acceleration (when you nail the throttle). Guess it depends on one's definition of a "bog". Things like that make it hard to help over the net.

dviga001

I got the WOT bog too with my firestorm. I thought it was to lean and was not getting enough gas but there was still a lot of smoke coming out.

this made me lean it out which eventually is what helped

RCtruckRacer

Argess: You definately can have a rich bog. An engine will bog down anytime the air/fuel mixture is off enough in either direction. It's just been my experience that most people find it easier to tell when an engine is too rich vs too lean. So, I have seen far more lean bogs than rich bogs.

tcv_racing

After reading the posts of all the guys saying that they bog at WOT due to rich mixture I therefore conclude that the bog that Im having with my storm is what everyone knows as a "Rich Bog".. The next time I run it I'll put both HSN and LSN to factory settings and re-tune the engine step by step from the beginning..

Thank you all so much for all your replies! It is really a BIG help specially to a nitro newbie like me.. +100 to all of you!!!

buggymangp

hi guys
thought i`m chime in here.
my storm had a WOT bog too.
i only had to lean it out (HSN) about a 1/4 turn from the factory setting and its been fine
ever since. i never touched the LSN.
my storm wheelies like crazy. almost to the point i might change out the CB for higher gearing(21T).