hey guys, i'm new to this forum, but i play to give back..

Here's my problem:
i used to run 10% fuel, then i decided to upgrade. i used about 2 tanks of my buddys 20% and it ran much better. So i go to my hobby shop and buy 30% thinking it will be even better. But i get home, run a tank, 3 minutes in, it starts stalling, and i can't get it to start. I am new to this, anyways, i richened it. nothing works. now i go to prime it, and it's getting little gas, almost like there are huge amounts of bubbles in the line, it looks kind of like the tank is empty, but the tank was full. i put it away. take it out the next day, and bam, it's running pretty good. about 3 mins into it the run, does the same thing. i'm thinkin i have a hole in my gas line or somthing, but then i figured it wasn't because it works, until the engine gets hot. i let it cool for 15-20 mins, runs good for the first 3 mins. Does anyone know what's going on? i was thinking i might need a cold glowplug, but i don't know.

Thanks in advance!

very sorry for double post, but the engine is the pro .15

Do you watch yuor temperatures at all? Also 30% is not that good to run just for back yard playing. If you go to 30% you need to shim the head, richen it up and keep and eye on temps. 30% on a stock motor like the pro 15 will over heat like crazy unless you do some minor changes. You should not run other fuels other than what you broke the motor in with. 20% is the best of both. Use 20% with no more than 12% oil. 30 percent set up tha way you have it now will cook the motor.

twomanytoys is right, but how many gallons have run through the engine. It sounds to me like it may be shot.

yea...if you didnt richen it at first you BBQed that engine...if you did then add a head shim

If it was not shot before the 30 then it may be now.

I have only ran about 2 quarts through with the 10 percent, and only about 3-4 tanks of the 30 percent. i did richen it up, i tried some of my 10percent fuel today, it seemed to work better. i better not use anymore of that 30percent. if i only ran a few tanks through it, think the engine should be fine?

It looks like the motor was overheating and thats why you were having problems. If you onl ran a few tanks you should be ok. Run the rest of your 10% and then switch to 20%. If you use the 30% you would have to shim the head.

whew, 30 bucks down the drain in 30%, but the good news: i hopefully don't have to get a new motor. and also, is a hot glow plug ok for 20%?
thanks alot for your help!

Yes a hot plug is good. rule of thumb is that the lower the nitro the hotter the plug and the higher the nitro the colder the plug.

yep, i did alot of research, but not enough i guess, i should be totally fine with 20 percent righht? and i should prob invest in a temp gauge.

Yes on both. I like to use a temp guage. Once its tuned its not as important but it really helps in tuning. Then all you have to do is minor adjustments if any when weather changes.

How do i tune it to temp, could you try to get me a tutorial, thanks alot for the help again.

id say first tune by performance, smoke, and sound. make sure its not bogging down or cutting out and make sure theres a healthy amount of smoke from the carb, then check the temp to make sure you didnt go overboard. good temps are 240F-280F

You dont really tune to temperatures or it will be a tuning nightmare every time you run the truck. All you need to do is tune for performance and watch your temperatures when you think its running great. If the temps are too high after running for a few minutes then you know you can richen it up a little. If its running too cool then you lean it out and get more power. Once you are in the ball park you wont need it as much untill weather really changes. Some guys go by seeing how much smoke it puts out but thats not at all accurate. Some do a water drop test. Yes its fine in a pinch but nothing is as good as a temp guage. Expecially for a nooby. When I race I do some runs and lean it out for the race and I watch the temps for about 5 laps. If my temps dont shoot way up I know Im good for the rest of the day for racing. Its good insurance.

you are the only person that ive heard say that

great advice, thanks. and how will i know what temp it should be at, should be in the manual somewhere?


edit: What about those "flash point temp gauges" are these any good? and if i get an on-board, how does it connect? also, i just seen the post with the temp, thanks.

Here is why I say this and I do read this all over.

I had a brand new Picco on my T maxx. Once I broke in the motor I could not get it tuned right for the life of me. It had great smoke and great power but my idle was never right. Every time I started it I had to re adjust the low end. Temps were all over the place and times I could not get it below 300. Even at its richest point but smoke was always good. Come to find out that Picco was covering motors under warranty because of airleaks. Once I got the new motor from Picco adn got it tuned it was great. Now just recently I bought my son his first nitro. I bought hin a Redcat Tsunami. Great little truck but I was having the same problem with over heating. I went and sealed the motor and did every thing I could to get temps down with no luck. Again lots of smoke and good top end but temps shot up to 280 every time. Come to find out that the carb was bad. I put an os carb on it and retuned it. It runs great now. Smoke was always good and if I did not have a temp guage I would have cooked 2 motors. Thats the only reason why I say the smoke is not always a good indicator. You can have an airleak and smoke can be good but temps can get very high. My Jato is tuned great adn all I use on that is an onboard temp guage just so I can see it on a pass by but while tuneing I used my point and shoot.

I did not mean its not at all a good indicator I meant to say its not allways an accurate indicator.

logical, i'm really hoping i didint fry my motor, becuase i had the high all over the place, it's recommended 2.5 turns out, i had it from 2-3 turns out trying different settings, but i did run rich with the 30%.

well, sometimes if the engine gets soo hot, the carb will evaporate the fuel, causing it to cut out. it should be fine though. hey thats not waisted fuel, get some 10% and mix them togather it will work if its the same brand. i accedentally ran my engine soo hot that it melted the air filter, due to over leaning. but it still fired up after adjustments.


i never tune with a gun, i tune by sound, proformance, smoke and ,most important heat. guns can be inacurate, but you have to know what your doing, you can use the water drop test, this is when you place a drop of water on the head and see how long it takes to evaporate. more than 10 seconds is rich, 7-5 seconds is peak, 4secs or instant evaporation is over heating.

thats why i said to then check it with a temp guage to make sure nothing is wrong

Thank you, i think i'm gonna try to get a mixture of the water test, smoke, and temp gauge so i can tune near perfection. What should the smoke look like on idle, acceleration, and high speed?

Also, what do you guys think about the "laser" temp gauges?

smoke amounts...idle- none low speed-healthy amount, as long as its not bogging down high speed- a little bit less than low speed as long as its not bogging or cutting out

alright, i took my truck out today, worked really good. it's bogging a little at the top, but i'll play with it.