GeeBeer

Hi, I've got a new TowerHobbies .75 for a 4*60 to toy around with (Relaxing sport flying)... plane is almost finished (Kit). While playin with the tower .75, I noticed that it is EXTREMELY tight. I put a prop on it... tightened the prop nut... and tried to turn it over... This thing is soooo tight... I had it in my gutt... hand wrapped around the prop.... and got it to complete the "UP"... I mean this is a struggle.... prop (Wood) flexed a couple times... thoguht it might break. Same thing back down....

Now I know that ABC's are tight new.... but this seems excessive. How am I supposed to start it if one cannot even turn it over? Will it become easier with fuel in it?

I've had quite a few motors in the past... and never EVER seen one this tight.... Is this normal or should I give Tower a call?

edgeguy

My Feedback: (16)

Does the engine turn over easier when there is not a prop tightened on it?

If so It may be missing a washer between the front bearing and the drive hub. This will allow the drive hub to rub on the engine case.

Just an idea I had this happen to me before.

AndyF

My Feedback: (2)

Snaught,

You might try removing the glow plug and flipping the engine over after attaching the prop. It should still have friction at TDC but should flip over easily. If not, you may have to return the engine.

Regards,

Andy

GeeBeer

Nope, prop off... there is absolutly NO chance of turning it over.... ya need the leverage Also... Glow Plug off.... its a LITTLE easier to turn over... but still a chore.

AndyF

My Feedback: (2)

Snaught,

Sounds like you may need to send it back. There should be resistance but not that much. They are real tight right at the top but you should be able to flip it by hand.

Andy

Dauntae

Actually a friend and I both ordered Magnum engines and mine was a little tight but his was real tight, If your turning it over dry you could be doing damage so try putting a little fuel in it and see how it is lubed up. His was tight but started right up and after breaking in a little it really reved right up and turns over real nice with great compression. Best of luck and remember to never turn over a dry engine, It's like running your car without any oil in it.

Dauntae

vinnie

My Feedback: (1)

You might try warming the cylinder with your heat gun. If that eases the tightness somewhat then warm-and-start. Should be ok.

G.F. Reid

My Feedback: (1)

With an ABC engine, the tighter the better I think. George Aldrich was the first that I remember to say this and he would actually check them out when buying and get the tightest one he could find in the bunch.
I agree on not turning it over much dry or at all until it's been run a bit. I always start these types of engines with a backflip. The compression is so high, it'll take off running in the right direction. A soon as it starts and gets hot, it'll loosen up a bit. After running about 8~10 ounces through it, it should be nice and smooth.
I have an Irvine 53 that was like that out of the box and it worried me until I started it up. It's fine now.

Volfy

My Feedback: (23)

I doubt there is anything wrong with your engine. Most ABC 2strokers I've bought, with the exception of some OS engines, are very tight around TDC. My Magnum 1.08, the largest ABC 2stroke I have, was so tight when new I had to buy a Dynatron just to start the sucker. After it was broken in though, it runs silky smooth, idles low, and makes a boatload of power. Curiously, there has been very little wear near the crown of the piston, so it does take much interference fit to feel extremely tight.

I've learned to fight the urge to turn the engine over by hand. Most engines come from the factory pre-oiled, mostly for rust protection purposes I think, so it's okay to crank it around a little if you must. I always re-oil my new engines anyway to make sure there are no dry spots.

Bax

My Feedback: (11)

Snaught,

ABC-type engines can be VERY tight at top dead center. The key to starting them is to bounce them off compression backwards. A lot of pylon racers in the 70's and 80's started their engines this way. You snap the engine backwards using the spinner. The motion is kind of like snapping your fingers.

Don't try to start a tight ABC-type engine at idle. You'll need 1/4-1/2 throttle, at least. Once it starts, don't remove the glow plug battery, but immediately advance the throttle to full. Once it's at full throttle, lean the engine so that it's not running in "4-cycle" mode. "4-cycling" an ABC-type engine will only ruin it.

You can lean the engine to peak RPM as soon as it will accept the needle, although 30-40 minutes of full-throttle running is usually needed to get the rest of the engine loosened-up for good performance. Gradually lean the engine during this time.

ABC-type engines like lots of oil, and you should be using a blend with castor oil in the oil package.

cwat212

The Tower engines are extremely tight. I could not turn mine by hand until after I started it the first time.

Add fuel and use your electric starter. It will loosen up.

rsieminski

I agree with most everyone else, never turn over an engine out of the box. I always, open it up, rinse with fuel, thoroughly lube with a good after-run oil. The tighter the better! For the 1st run, heat the head a little with a heat gun. Use lots of oil, at least 20 %(I use 22-25%) fuel for the break-in. Short, 5 min full throttle runs, the 1st being just breaking into 2 stroke. Do this 5 to 10 times, with 10 min cool down in-between. When it'll hold a nice clear 2 strike full throttle note, it's ready to fly, rich. IMO, if it looses that pinch, it's garbage(unless ringed of course), time for a new liner and piston. Have you ever turned over a brand new Jett Engineering engine? That's tight.

http://www.jettengineering.com/faq.html#faq8

upnflyin

I just broke in my new tower hobbies 46 and it sounds just like your 61. I even called their tech and talked to them first. It started really hard to turn over but when it did start it sounded like a small block chevy with a rod knocking. Was sure bad sounding. Ran 4 tanks thru and it is really a nice engine now. Go ahead and give it hell.
Al

GeeBeer

Thanks for all your imput.... I feel a lot better now about hte engine. I also will not turn any engine over right out of the box... I never knew that Luckily... this one only went over maybe 3 times? I cant wait to fire it up!

Keith

rsieminski

Keep it a little rich, especially if you do a lot of vert maneuvers, and it'll last a long time. I give it the pinch test: Tune for max rpm, then back off a click or 4. Give the line a quick pinch, if it speeds up a bit, rock-and-roll, if it just cuts out without speeding up, back down the needle a few clicks again. To double check, point the nose straight up, if it looses rpm, it's too lean, and back it off a bit.
Best of luck,
--Rick

dahoppa

my tower .46 was a tighty sucker too. heat is the answer, expand that bad boy a little. also , i put a drop or 2 of motor kote on my piston 1st. turning those abc's over "dry" is not a good idea. scratch that crome, or gouge that piston and yer in for a short lifespan.