Hello all! I'm trying to break in my first glow engine, A Tower .46. In the manual it says to "pinch" the fuel line and the engine should pick up speed, I was just wondering what a "pinch" is? am I to completely pinch off the fuel quickly, or just squeeze to reduce flow? Ive been trying a full pinch but every time the engine just dies shortly thereafter.

Any help is appreciated

Cheers,
Derek

Pinch it off completely and rather quickly.

Oki doki. Thats what I figured I was doing wrong, Holding the pinch a tad too long. Thanks for the quick reply!


Cheers,
Derek

Yep, it's just a quick pinch and release.

Ken

I've always been under the understanding that the "pinching" test meant to pinch off the fuel line close to the needle valve totally until the engine dies. If your engine dies very quickly without speeding up....it is too lean. If it takes awhile to speed up then dies.....its too rich. If you pinch it and the engine speeds up and quits within a few seconds.....that is what your looking for. Either way....I was never a fan of the pinch test because its just too vague,and should only be used to aid in tuning. Keep in mind,the pinch test is done at idle too I think.

Actually, it can be done both ways.

Brief pinch.
With the throttle wide open lean for max rpm then back off 2-3 clicks and then briefly pinch the fuel line. The engine should speed up and then back down if it's set properly. If the engine doesn't speed up or dies then yoru still too lean.

Pinch close
WIth the engine at a fast idle pinch the fuel line closed and hold it. The engine should speed up and die in about 3-4 seconds. If it takes longer then the low end is too rich, if it takes less time or if the engine dies instantly the engine is too lean on the low end

Ken

So, in my case, when I pinch the line the engine slows, then finally stops 2-3 seconds later. Does this mean the setting I have it on is to lean?

When you pinch the line the engine should speed up, and then, if you release the pinch quickly enough, slow down again. If it dies on a quick pinch, it is too lean and you are doing it harm.

Thanks Jim! Right after your post I took it out, richened the needly a bit and got it to the point where it sped up with a pinch and ran a tank through it. Thanks for everyones help, I love this board


Cheers,
Derek

God, the TH .46. If I were you, I would just get an O.S. .46 immediately. The tower is a pain!

Ken, I was told for the low end that you should pinch the fuel line, and that it should run for about 8-10 seconds before it quits if it's properly tuned. . . . Incorrect?

Bad experiences I take it? I don't know, the whole experience of breaking in an engine has been rather intimidating, I don't want to ruin the engine before I even fly Pinches, Screws, pitches, it never ends!

Solace,

Great post.. I am a newbie myself and have not even purchsed my engine yet (I am going with an OS Max .55 for my Goldberg Skylane 62 ARF) and this will help me to better understand what is meant by "pinch" should OS recommend same "test".

So, even tho it has been a pain, it is helping others like myself, in which I am appreciative. Keep your head up, and let us all know when you get'r up.

Best of luck, and take "solace" in the fact that you are almost in the air!

Peace.

- Don

solace67,
I'm not sure about the .46, but I have a TH .61 and they use a pinch test for both the low and high end settings. Are you setting the low end or high end? The engine response you're looking for is different for each. TH engines are a little more complicated to break-in and the instructions definitely leave a lot to be desired. Once broken in, however, they are very reliable. If you can, have an experienced modeler give you a hand. Just remember to be patient and give the engine time to accept the new needle settings.
Good luck
Rufcut

This was as I was adjusting the high end. I haven't done the low end yet, as I may have to wait for someone with a bit more experience than I to help me not 100% sure what the idle speed should be set at. I've heard some say as slow as you can get it without it dying and other like it a bit higher than that. So we shall see. It seems to be running good, I haven't had it quit on me, so I have high hopes!


Cheers,
Derek

Oh, c'mon.

You had a fuel line problem and you fiddled with the needles. Don't go bashing the T.H. .46 for this, it's undeserved.

If you leave the engine alone and you set up the fuel lines correctly, it will start up right out of the box.

The O.S. is certainly a nicer and easier engine for a newbie, but the T.H. is by no means a "pain".

Yes. It should be slightly rich.

I'd use the acceleration test myself.

I never had a fuel line problem.

Thanks for the post .I'm still at the studying stage.But when i get my trainer and first engine,I'm sure this will be a come back to post.

In your other threads what you described seemed to be caused by an initial fuel line problem, then by changing the needles, you ended up with a new hard to tune engine.

If the needles are left alone on the T.H. it will start up right out of the box. You can run a couple of tanks through it as it comes then start tuning it.

I've done many this way. The only time I've had problems is when I did not follow this proceedure.

Usually it's start, run a few tanks, tune and fly with them.

They are not bad at all.

I have a Tower .46 and .75 and I have to compliment both of them. They both have great power and are reliable. I haven't had a single deadstick with any motor, including the Towers. I haven't even heard either of them skip a beat in the air. Idling is a plus for both of these. I haven't had to adjust the low speed needle on either of them and they will idle for a full tank if you let them, then transition to wide open without a hiccup. I can honestly say that the .46 is the best running 40 sized I have owned.

HOWEVER, you must make sure the carb is seated all the way down, and you must have some idea of how to tune a motor. I didn't think it is a challenge to tune them at all. I realize that there are easier to tune motors available but a couple more minutes doesn't make a difference to me. As far as breakin is concerned, I did the same with any other motor. Run them on the rich side for a couple of tanks, then progressively lean them for a couple more. Then they are ready to fly and finish breakin in the air and continue to get better for up to a gallon.

Sorry about the rant, but these motors deserve a little more credit than they have been given. They are good motors and they serve their purpose on a budget. That is, if Tower ever has them back in stock [:@] !

If the engine just dies the mixture is too lean