TRYING TO BREAK IN ENGINE
 

I am attempting to break in my PT-40 powered with a A.P.S .46

I had it running nicely but when I shut the engine down (I do it by squeezing the fuel line to the carb) it stopped solidly as if it just froze. Now when I flip it (yes, I use a chicken stick) its like the piston and prop shaft is tight and it will sometimes be stiff when trying to flip it and the prop will not turn over properly but will just stop solid.

What did I do and how can it be remedied? The engine has never flown before so it was never in a crash.

RE: TRYING TO BREAK IN ENGINE
 

A lot of variables there. I would have to tear it down and inspect it before moving on.

RE: TRYING TO BREAK IN ENGINE
 

Again need more info. When running to break in was it running very rich just rich or lean. What fuel? High throttle, or where? From what you said it quit when you pinched off fuel line. This of course would make it very lean and if already running lean it probably overheated badly.Proper break in is to run rich at full throttle then vary needle setting from time to time to allow it to run rich and cool off. After several tank fulls you could try varying throttle setting on occassion. Sounds like you cooked it bad or broke crank.

RE: TRYING TO BREAK IN ENGINE
 

How does it turn over with the glow plug removed?

RE: TRYING TO BREAK IN ENGINE
 

Dont' know much about rich or lean but if it helps at all it stops almost immediately when I pinch the fuel line.
I start it at highest throttle. The fuel I use (recommended by LHS) is 15% nitro with 20% oil. Says on the can for helicopters, but didn't notice it until just now. Does that matter any?

I can almost get it running now, but ocassionally it will stock up and not flip, but very seldomly now. Gonna charge everything tonight and try again tomorrow.

RE: TRYING TO BREAK IN ENGINE
 

If the engine died immediately when you did the pinch test you had it running too lean. Too lean equals damage to a new engine most of the time.

Ken

RE: TRYING TO BREAK IN ENGINE
 

Sounds lean to Me. See if a member of Your local club could help You tear down the engine.
If things look ok, apply plenty of after run oil and put it back together. This time, open the high side up to the point that is losses considerable rpm’s and let it warm up. Use short runs, five minutes at most, lean it a little each time.

john

RE: TRYING TO BREAK IN ENGINE
 

How do you adjust the leaness/richness of the engine? With the needlevalve or the screw on the opposite side that I hear people talk about? I will be looking for an online manual for this engine sometime tomorrow.

RE: TRYING TO BREAK IN ENGINE
 

Good luck with your search on finding an online manual. You may also want to visit Minn/Ken's site Getting Airborne. I linked their [link=http://www.gettingairborne.com/engines.html]engines[/link] page for you as there's a great deal of information a beginner should know right there.

I'd suggest getting a working understanding of 2-stroke engines before going much further (an instructor or assistant at your field would be invaluable right now). Venturing out on your own with little to no knowledge of what rich/lean means or how to correct is likely going to cost you - possibly the engine, maybe worse. I'm not trying to be harsh, but it sounds like you're a bit over your head here.

-MA

RE: TRYING TO BREAK IN ENGINE
 

ABC-type engines should feel tight even with the glow plug removed. There'll be a pinch at TDC, which gets a bit less noticeable as the engine gets some time on it. It's best for the engine not to sit there and play with it, turning it over and over through the pinch. ABC-type engines need to be at operating temperature for the cylinder fit to be correct.

RE: TRYING TO BREAK IN ENGINE
 

Yes but this "feel" should be noted before the engine run for the first time, if now, it feels like it is hard to turn even with out the glow plug then in my thoughts it appears that the liner got distorted because of an overheated condition. Like jeffie8696 I would tear down the engine and inspect it carefully, if the liner is distorted it could not be appreciable at simple sight but you can figure it out by the color of it. (Blue)

RE: TRYING TO BREAK IN ENGINE
 

The last thing a beginner should do is tear down their engine. Their inexperience leads to tuning problems, and tuning is simple. Getting everything put back together takes another level of concentration and competence.

If a person has doubts about what they're doing, the first step is not to take it apart. The first step should be to seek competent help in person.

RE: TRYING TO BREAK IN ENGINE
 

I have to agree with MikeL here. At this point I would urge Shd3920 to seek out the help of an experienced modeler, or maybe a LHS. Inexperience in how to tune and engine for break-in may have caused serious damage to the engine. And if it's not toast already, improper breakdown and trying to reassemble could very well kill it if it's not already dead. I'm not trying to be harsh here, but actually I'm trying to help. If you're not even sure where the needle valve is, and it's proper settings for tuning an engine, then it's time to stop where you are and seek out help in this. RCU is a great source of information, but there are still times that having a pair of real world eyes and ears can be the best help of all. We can tell you how to tune, or break-in, an engine here. But a real person can show you instead.

Ken

RE: TRYING TO BREAK IN ENGINE
 

I know where the needle valve is and that it tunes the engine. Its just I heard that a screw on the opposite side (near the throttle arm) adjusts some function as well.

RE: TRYING TO BREAK IN ENGINE
 

There's a couple of them, and depending on what kind of engine you have they do different things. There's a set screw that holds the throttle body in place. On some engines this also limits the movement of the barrel. If it's an airbleed, the airbleed screw controls the lower-throttle part of the mixture. If it's a twin needle, there's a low-end needle valve. Adjust your engine purposely, rather than haphazardly.

You'll find a huge advantage in this hobby by taking the time to learn about your engine. You don't have to be an expert by any means, but doing a bit of research and reading (starting with your manual) will pay a lot of dividends. There are always people at the flying field who spend a lot of time messing with their engines. They do things like adjust the high-speed needle with the engine at idle, turn this screw or that one just to try changing something, or start messing with god knows what. Investing a few hours in theoretical knowledge and practical know-how (someone to actually show you how to properly tune an engine) will save you a lot of problems. Fewer deadsticks, fewer burned out glow plugs, and engines that do what they're supposed to do.