I took my recently built Savage X SS out last night for it's 1st hard driving session as I wrapped up the break in procedure last weekend. Everything went great.

One quick question about tuning. I thinkI figured it out, but just want to make sure.

When doing high speed runs the engine would lose power until I let off the throttle. It only would happen whenI gave it full throttle and only after it reved up for a few seconds.If I slowly built up speed all the way to full throttleit wasn't as severe, but ultimately it would happen. I brought it in and checked the engine temp and it was 310 degrees - way too hot.

I richened it and it fixed the problem.

SoI am guessing this was a situation where it was to lean and the engine wasn't getting enough fuel to continue to run? I am trying to figure out not only how to tune, but how things are affecting the motor so I can understand what is happening, and not just which way to turn the needle.

After last night Ican see why tuning an engine is an art with a learning curve.I warmed the engine up at a baseball field and got it running great - good response, punchy acceleration, etc. Well,Imoved spots to a construction zone, got the car out and it was then running to rich. It took all of 15 minutes to change locations and the tune was already in need of small adjustments. Also, it's amazing how much change in performance just an 1/8 of a turn of the HSNdoes when you are near the "sweet" spot.

Thanks
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Was this after a little time running, like after the first 4 mins or so? If so, then you are a victim of the classic 'half-tank-lean' condition. Basically, as the fuel level drops, so does back pressure, causing the truck to run too lean for the second half of the tank. There are various measures you can take to solve this, and you'll find a lot of info in the HPI monster truck forum about it.

PS. I'm sure you realise this, but 310 won't have hurt your engine if you just do it once or twice, but try not to make a habit of it Mine used to run at 290-300 on an optimal tune and never had any problems. The stock engines tend to run a bit hot.

When the engine can't maintain full power at WOT, and then runs better at lower speeds, this is typically too lean a high speed needle. You learned this already.

Get used to turning in increments smaller than 1/8 a turn. More like 1/16th and 1/32nd a turn as you become more familiar with your set up.

If you want to use a thermometer, that's fine. But if you learn to do everything without one (like I do), you will achieve Zen Master status in the rhealm of model engines. You will learn the most about model engines by relying on your own instincts, judgements, and senses as opposed to using mechanical and electrical "aides."

Know the sound and smell of the engine. Know the response (or lack there of) of the model. Be the model. You have to get in there, and crawl around a little.

Your engine is still new, and not completely broken in. After about a gallon it will start to hold a tune better.