s7jstep1

i just got a used revo 2.5R and when i run it for about 1/2 tank of gas, it looses power and stalls. it is hot but i dont know if it is too hot.
i can restart it but it will die shortly after. any ideas?

GRANT ED

Richen the HSN a 1/4 turn and try again. You may need to do this a few times to get it right.

happywing

Don't do anything until you get a temp guage. True, tuning by temp is not the best way, but when you're new it might save you some money. I don't know why people spend $500.00 to get into nitro and then don't spend the extra $30.00 for a temp guage.

joes75

My Feedback: (2)

Sounds like it could be a couple of things, either its a tuning issue or the engine is at the ends of its life. The stalling out after reaching operating temperature is classic symptom your engine needs a rebuild.

s7jstep1

the guy i bought it from said he was having problems with the original engine and so ha sent it in to traxxas and it was replaced. he said this engine only had about 1/2 gallon of fuel through it since break-in. he told me that somebody told him that it needed to be tuned but i cant get it tuned. this is my first nitro rc.

bozla

I agree with the other guys. Sounds like its running too hot (so richen it, it will reduce power but it will run better) or that the engine is at the end of its life. When the engine gets up to temperature, do the revs rise and fall (i.e. are they unstable?) This will tell you that the engine is running too hot. One thing to try if nothing else works is change the plug. Its always recommended to change the plug after break in.

SAVAGEJIM

Everyone brought up the point of richening, which is a good first step. But happywing brought up the use of a temp gauge. I feel a temp gauge should never be discarded. It is possible to tune an engine way too lean even if the engine shoots out tons of smoke and never makes an off-beat sound. This is because different fuels might have a higher oil content. Higher oil does not necessarily keep an engine cool; the additional oil will just burn and spew out more smoke just like a full sized car with a hole in one of its pistons or a seriously worn piston ring such that oil gets into the combustion chamber.

Go ahead and tune the Revo as usual and listen to all the tuning cues. Then, to verify everything is proper, temp the engine and keep it under 300degrees F (must will actually say keep it below 275degrees F). The temp is simply a sanity check and should be used to verify that your tuning skills are correct for the engine, plug, fuel, pipe, outside conditions, etc.

Also, you must learn to take the temp properly. If you already know, then disregard this paragraph. When you take the temp, do your best to aim the temp gauge at the glow plug. If you miss the plug (and you will most of the time), you will get a false cooler reading (another reason why many say temp gauges are BS). When fully warmed up, I always take a battery of 5 readings in one setting and look at the highest #. Then I go for another pass, and take another battery of 5 readings, then go for another pass and take another battery of 5 readings. This is overkill, but I want to be 100% sure of the actual temp. In all, I take 15 readings to get what the engine temp is.

GRANT ED

OK here is my advice. As a newb do not rely on a temp gauge. It is a useful tuning tool but do not follow it blindly. People have been tuning nitro engines for years without temp gauges. As you become more experienced they will become useful but IMO a temp gauge for a beginner can be misleading.
At least for now do not worry about people telling you your engine is shot. Deciding to replace an engine because its hard to tune (especially considering this guy is new to nitro!!) should be considered and absolute last resort. It’s easy to tell someone that they need a new engine when it does not cost you personally anything.
90% of engine running tuning probs can be fixed with the needles.
First things first, richen the HSN. It will not cost you anything and will tell you what’s going on with your engine.

**MilkMachine**

Im going to totaly agree with GRANT ED, a temp guage is a great helper. But for a begginer in nitro it wont be a smart idea for him to use that for tuning. He should figure out how it reacts to throttle when lean, or to rich. And has anyone ever mentioning throwing on a new hot plug? The plug could be old and after it staying glowin for a while it could just kill itself? Sounds like a long shot, but you never know. Ever think maybe he was running rich in the first place? That could cause stalling.

One question reguarding that though, is the engine bogging when before it stalls/dies?

happywing

No, a temp guage is not for tuning. For me, it is just a little helper to give you piece of mind. In other words, I can do a lot of experimenting with tuning and if my temp is OK, I'm not going to ruin my engine. I learned to tune by making changes and then watching/listening compared to performance. Doesn't take long to figure out the "if/then." With no temp guage, I don't think I would have been as aggressive with my experiments. It's a good learning tool.

s7jstep1

problem solved. i took it to a hobby store and they tuned it for me. now its time to have some fun.