infernoMP

I dont know if any of you guys have had the same problem or not with your revo's. I'm running traxxas top fuel 20% nitro with the standard glow plug. I'm running in "normal" humidity, 70 degree temps at 1500ft above sea level. The problem is...when I start my revo and run it for a few minutes.....it always starts out rich....running 190-205. After I turn the needle 1/12 of a turn on the HSN needle it starts running very good and the temps run around 220-230. When it starts to near the end of the tank...say around 1/4 tank left. It starts to continually get hotter and hotter. I'll richen the HSN 1/12 after 1/12 and the truck continues to run well around 240ish. I just dont see why I have to keep richening it up after 3/4 of the tank is burned. If I leave it alone for the whole tank the temp climbs above 260-275 although it flys when running those temps. Please help!

rozzibandit

My Feedback: (1)

What type of fuel are you running. I was running byrons and had problems liek that , over heating alot. I switched to Traxxas Top Fuel 20% took my time in tuning the motor and my problem dissappeared. It still gets a lil leaner at the end of the tank like your saying. But all my 30 sized helis do that as well. The 90 sizes do not because they have a fuel pump on them. One thing you can try is putting a 1 way fuel filter(valve in line with the carb) that should help. It did minimize the leaning out near the end of the tank for me. But I highly recomend using traxxas top fuel 20%.

infernoMP

I'm running the traxxas 20%. I tightened the seal around the top of the tank and got some results out of that. It just seems like it's starving itsself toward the end of the tank. Like there's not enough vacuum to get the fuel pumped out near the end. I really dont know though....

infernoMP

Can someone please tell me if these are the shock ends I need for my Revo. I broke one today while bashing and I dont want to order the wrong thing. It's not on the parts list so I need to know for sure. http://www2.towerhobbies.com/cgi-bin...69&FVPROFIL=++

Mr.Pathfinder

to be honest with you i have the same problem with my tmaxx what happens as the tank gets lower to the empty point the motor gets leaned out so actually what i did on my truck was to fill the tank at half full run the truck and keep a very close eye on the tank and then tune the motor. cause when you fill the tank the truck will run slightly richer and when the tank runs to it's half mark it should be pretty close with the temps rising you are running too lean and if you keep turning the hsn you will get your results but as soon as you fill it the truck will be running rich. So what i would do is run the truck at half a tank, try to maintain the half mark level and tune it and keep filling it to a half tank until you get your adjustments right running good temps, and producing a small trail of smoke. (if you don't know watch the dvd that is how much smoke you want the truck to produce on the intro). then when that is done fill it time it then you will know how long you can drive before it's time to refuel. Traxxas even told me that this way is a very good idea. cause when the tank is full it runs the richest the lower it gets the leaner it gets resulting in higher motor temps. i think what happens is that the motors don't produce enough air to go into the tank to push the fuel as when it's full it can push more fuel cause more air is trapped in the tank creating more force versus 3/4 empty but that's my theory. But if you like to run the truck all the way to a quarter of a tank on average than i would tune it to that point. but then when you fill it up it will be more doggy. just thought i would help you out with some info
sincerely
brandon

rozzibandit

My Feedback: (1)

Well said Lad !! Those are the ends you need to.

jucara

I found this over at RDracingproducts.com

http://www.rdracingproducts.com/foru...?showtopic=118

I cut some holes in my airfilter, and it seems that the tuning now is much less sensitive and easier to deal with, also gave me a much better idle, and low end takeoff, filter doesnt clog as fast either.

psycooclimber

whats happening is when the fuel level is low and you go over a bump it sucks in a little air. the lower the fuel level the worse it gets. the length of fuel line helps correct this but a fliter will stop this from happening ( it works like an IV drip in the hospital).

califax

its been consistant for the trx 2.5 engine to leak air through the carb. Try this, to get an air tight seal where the carb meets the engine remove the carb and add some silicone sealant or a sealant goo. after doing this I noticed I no longer needed to adjust my needle settings with my t-maxx, which made it hold its tune. You can ask alot of T-maxx owners that have done this, and they will probably tell you the same thing. I had the same problems you are having, but I sealed the carb to the engine and all my troubles went away...except for my weenis being short shriveled and pointed to the left!

davechappelle

I hope you like changing piston and sleeves (-: ....I guarantee you will not get more than 1 gallon through that engine. All that you are doing is introducing less air restriction (and more dirt) into the engine. The same thing can be done by leaning out the engine (without the dirt in the engine problem as a result). oF ALL THE THINGS THAT YOU COULD POSSIBLY DO TO THE ENGINE, THAT IS BY FAR THE ONE THAT WILL CAUSE THE MOST DAMAGE. You can change anything you want, but don't change the air filter.
About the post regarding the t-maxx owner having different tuning when the tank was full, the reason why that happens is the tmaxx tank is taller than the height of the carb. The revo doesent have that problem. I would suspect that the air leak that the revo guy is having is because of the fuel tank o-ring. Now that is if you are having overheating problems at all.....remember, the 2.5 engine will run between 240-270 all day long, so you may be alright where you are, you know?

Anyway, bottom line is, call traxxas for a new tank o-ring, get rid of that Mickey Mouse air filter setup (no offense) and clean and oil your air filter often.

redheat8

Personally all three of my 2.5 engines run from 240 to 280 and there fine , i think that people are getting all worried for nothing, OK now I'm sure that I'm gonna catch some heat for what I just said and I understand peoples concern that they might do damage to there engine but I have not seen proof of that as of yet, I run mine at 3.1/4 out on the H/S and flush on the L/S, for the plug I use either MC59, MC8 or the OS LC3 and fuel Trinity Monster Brew 20%, and I've never had a engine fall apart on me , RED

fhm101

Here's the deal on the 2.5 and the assorted tuning issues. The composite carbs are like indian arrowheads, no two are exactly alike. Of the dozens I've looked at (torn down and rebuilt) almost every one had it's own unique issue. If you get a good one you are golden, if you don't some can be saved and some can't. I would say tear down your carb and check for cracks, slides that don't fit right, casting flash, mangled O rings, partially plugged fuel inlet, etc., etc., etc. Make sure the access plugs in the body are sealed, it usually takes a bit of silicone to get them 100%. I can see where someone that gets a good one would think anyone having trouble tuning one would be lacking in the requsite skills, but that's not always the case.

fastcrash

2.5r-odonnel 30%-mc-59-220 to 240 deg. all day long. if i beat the everloving pi$$ out of it it might hit 250 deg.

chetscc

What kind of silicone do you guys use on your carbs?

Thanks in advance Brandon