EXTREME1
RCTalk Talkaholic
my revo 3.3 is running hot very quick.i called myself checking everything.but i've got to be over looking something.any sug.?
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If it seems to be running good, the main cause of a quick overheat is the LSN being too lean. If richening it doesn't cure the temp problem you'll have to check the entire drive train for something binding which causes the engine to work very hard.
2revo1maxx
Hardcore RCTalk User
Just set the lsn at flush, use a small paper clip to set the idle gap, and turn the hsn out to 5 full turns from closed. Once you get it started and warmed up start leaning the hsn in 1 hour increments until it runs nicely. Be patient, and consider the fact that it may take a full tank of fuel to do this procedure.
That makes for a complete tuning. Just setting the LSN a little richer might solve the problem without starting from scratch.
lesclaypool
RCTalk Champion
Have you tried following this tuning guide fully? https://www.rcnitrotalk.com/forum/showthread.php?t=76808
EXTREME1
RCTalk Talkaholic
- Thread starter
- #6
thanks i will try that next time out.
lesclaypool
RCTalk Champion
No worries! I have used that guide exclusively since the first time I laid eyes on it. If you really follow it spot on, it makes it so simple. My engines have never run better and easier. 
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2revo1maxx
Hardcore RCTalk User
I would do a complete tuning on it, the lsn isn't going to cause a quick overheat.
Yes it will. Something as simple as the LSN being too lean will cause it to overheat at idle. No reason to adjust the HSN if the truck runs good since it will NOT help an overheat caused by the LSN being too lean.
2revo1maxx
Hardcore RCTalk User
A lean lsn can take several minutes to make an engine run hot.
Set the lsn flush and richen the hsn.
Set the lsn flush and richen the hsn.
Wrong, but I'm not going to continue your argument. I probably have another 30 years experience over yours, but it seems my advise doesn't cut it with you. The advice is NOT for you, since you have your own way, but it's for Extreme1 in hopes that he can solve his problem in just a few seconds.
Lots of good info here:
https://www.rcnitrotalk.com/forum/showthread.php?t=60832
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JoeMAXX
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I have learned over the years the LSN setting on a Slide Carb is the hardest to tune and mostly ignored as Rolex says. If the the idle adjustment is correct which is about the thickness of a credit card and your engine stalls or loads up with fuel when idle then it requires adjustment.
From my experience if it stalls from not enough fuel richen the setting if your engine loads up to much fuel and starts spitting fuel out of the exhaust at idle lean the setting. Always make adjustments when the engine is at proper running temps between 160 to 190 degrees after a few mid throttle runs. Perform tuning in 1/8 turn increments and run for a few minutes then check again. You have to allow the engine to aclimate to new setting before adjusting again.
If you have any air leaks at all on the engine around the carb will run lean and that is when you need to break out the Copper Sealent and seal the carb up a little more then the factory sent it to you. This not very often but I have had brand new engines leak air thru the carb seals because the O rings were too small on the carb to engine and did not seal properly.
Every day is a new tuning day on a Slide Carb the older rotary carbs are much easier to adjust and just ran once most of the time you tuned them in. Most just required a little tuning on the HSN but the Slide Carbs in my experience require almost daily maintenance if you have drastic weather changes like I do out in Colorado. If I am out running in the morning and into the day and the temps increase by 10degrees on a slide carb I will have to richen the mixture as the day goes on and the temps increase.
Once you get the LSN tuned in properly it does not require much maintenance but the HSN in my region is almost daily this time of year.
Here is a good chart of adjusting HSN
http://www.xenonproject.com/tuning-your-nitro-gas-vehicles-engine-a-10.html
Now if you look at this chart I live at 6500 feet above sea level and humidity is generally below 30 % and I run Traxxas 33% nitro imagine my tuning 2 out of 3 says I should run a richer mixture and I run a medium heat glow plug. I look for smoke trail and try not to exceed 200 degrees on my engines.
From my experience if it stalls from not enough fuel richen the setting if your engine loads up to much fuel and starts spitting fuel out of the exhaust at idle lean the setting. Always make adjustments when the engine is at proper running temps between 160 to 190 degrees after a few mid throttle runs. Perform tuning in 1/8 turn increments and run for a few minutes then check again. You have to allow the engine to aclimate to new setting before adjusting again.
If you have any air leaks at all on the engine around the carb will run lean and that is when you need to break out the Copper Sealent and seal the carb up a little more then the factory sent it to you. This not very often but I have had brand new engines leak air thru the carb seals because the O rings were too small on the carb to engine and did not seal properly.
Every day is a new tuning day on a Slide Carb the older rotary carbs are much easier to adjust and just ran once most of the time you tuned them in. Most just required a little tuning on the HSN but the Slide Carbs in my experience require almost daily maintenance if you have drastic weather changes like I do out in Colorado. If I am out running in the morning and into the day and the temps increase by 10degrees on a slide carb I will have to richen the mixture as the day goes on and the temps increase.
Once you get the LSN tuned in properly it does not require much maintenance but the HSN in my region is almost daily this time of year.
Here is a good chart of adjusting HSN
http://www.xenonproject.com/tuning-your-nitro-gas-vehicles-engine-a-10.html
Now if you look at this chart I live at 6500 feet above sea level and humidity is generally below 30 % and I run Traxxas 33% nitro imagine my tuning 2 out of 3 says I should run a richer mixture and I run a medium heat glow plug. I look for smoke trail and try not to exceed 200 degrees on my engines.
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2revo1maxx
Hardcore RCTalk User
If you insist.
wacmartin
DAMN TREES
No worries! I have used that guide exclusively since the first time I laid eyes on it. If you really follow it spot on, it makes it so simple. My engines have never run better and easier.
+1 on that. I read multiply tuning guides, articles online they all pretty much say the same thing. But that one was just the easiest to follow, understand and there's a mountain of info in the nitro stickies section.
EXTREME1
RCTalk Talkaholic
- Thread starter
- #15
thank u all.i tried both the hsn,lsn now true enough once i started riching the lsn past the flush sugg setting (.25 out)my temps went from 270-248 w/ the hsn set @4 3/4 w/30% sidewinder race fuel.temp was 56 deg. so it was cool and was running it wot passes to the count of 5 thousand (no more than 3 passes)then checking the idle and if it sped up or shut right off when doing the pintch test.seemed like w/ my revo 3.3 4 3/4 hsn 1/4 lsn out from flush @ 56% run great!
but would like too get temps. down lowwer.
It sounds like you're still too lean on the LSN. Richen it some more, then after 30 seconds of running pinch the fuel line close to the carb. It should speed up and then shut off in about 3 seconds.
248 isn't a problem with that engine.
248 isn't a problem with that engine.
lesclaypool
RCTalk Champion
You'll know if the LSN is set right, if at idle (after some WOT passes and you're up to temps), it should drop a degree or so every 5-6 seconds. If it stays the same temp or climbs, your LSN is too lean.
2revo1maxx
Hardcore RCTalk User
You should also have a nice clean idle with no hesitation or loading up after at least 5 seconds of idling.
I would definitely NOT go richer with the lsn because you'll be heading for what's known as a "false tune". A false tune is when the lsn is rich and you lean the hsn in order to get some throttle response out of it. At 56° with 30% fuel the 3.3 generally could run richer on the high side, I would try that. I used to run mine at 5 turns out or more in cooler weather.
248 isn't bad, but in 56° weather that IS still a little warm. If it gets any cooler out you may want to wrap the head to help retain some engine heat.
I would definitely NOT go richer with the lsn because you'll be heading for what's known as a "false tune". A false tune is when the lsn is rich and you lean the hsn in order to get some throttle response out of it. At 56° with 30% fuel the 3.3 generally could run richer on the high side, I would try that. I used to run mine at 5 turns out or more in cooler weather.
248 isn't bad, but in 56° weather that IS still a little warm. If it gets any cooler out you may want to wrap the head to help retain some engine heat.
