Hi guys
Just bought the boomerang kit which came with OS .40LA and Hitech 4 channel radio. I went to the hobby store today and bought an electric 12v starter. Now i finished the final touches yesterday and thought id give it a go today and run in the engine. I half filled the tank with the fuel the hobby shop guy said to use. I opened the needle valve 1.5 turns and primed it like i should. The first couple of goes at starting it was with a prop stick. I got maybe 2 fires but nothing much. So then i opted for the electric starter. First couple of goes didnt do much. I suspected the fuel had not reach the egnine yet. This was comfirmed after a couple more goes when i saw the fuel start to flow from tank to needle valve and then into carby. It gave a couple of bursts and then fired. I dismounted the glow plug heater and it ran ok. Slowly advanced the throttle to bout 75 %. Anymore and the engine would start to run rough and end up stalling. So i ran it at bout 60% throttle for bout a min or so and then tried again. Got to maybe 80% throttle and then same thing.... I waited for what seemed to be ages and then tried leaning the needle valve by one or two notches.. this led to rough running at bout 60-70% throttle it stalled a couple of times and then after a while became very hard to start. Then here comes the final kick in the ass for the day. I saw that the yellow rubber thing on the starter was beggining to wear and there was quite a bit of rubber on spinner. So i slightly increased the pressure in which i was pushing it against the prop. Pressed the button.. maybe couple of revolutions and BANG!!!!!!!!! The starter slipped off the nose cone and smashed into side of front fuselage ripping about 15 cm of the the side.. leaving a crack down the joints. As i speak the 2 part epoxy i used on most of the plane is hopefully joining it back together.

Now two questions.

What the hell is wrong with my engine?

Will using the 2 part 30 min epoxy be strong enough to hold the joint together?


Any suggestions welcome

Neil

I would guess that you are trying to run the engine too lean. Open it up to about three turns and it should be very rich, which is better than too lean. Then lean it down to run. The epoxy should hold anything together that you can get it in the joint of. Good luck.

Thanks mate for youe help. Makes me feel a lot better now

Yeh just checked the joint... Even though its 30 min epoxy it still hasnt fully set yet...

I might leave the running in till i get down to the field this weekend and hopefully one of the guys down there can give me a hand.

You reckon 3 turns.. in OS manual they say 1.5... Can the engine suffer from a too rich setting


Neil

If that is what the manual says then it is a gross error. Smedsky is right on you are attempting to start the engine in an excessively lean condition then leaning it further. Nope you can not hurt an engine by a rich run but you can destroy one with a lean run.

Wait till you get hands on help and can learn a lot of the techniques like proper prime methods and such.


John

Cheers John.
Yeh thought that was the case..
Yeh i think i will wait till weekend and go to field.
It is very tempting to just find a clear open park that is secluded to try the beast out.

Neil

Neil, If it's a new motor you do know you should run a few tanks
through it to breake the engine in.. Just run it rich. I get my throttle
full open and just use the needle valve to keep the engine speed
low by opening the needle valve(rich) Then close to the end of the
first tank using the needle valve lean it out to higher RPM for short
period then richen it back down.. I run two to three tanks through
with rich running.. And you should keep it slighty rich for a few
more flights/tanks.. Or just read your engine manual and follow
its directions on break-in.. Let your epoxy dry first..

On the starter... They do that.. Luckily the engine did not start,
you could have cut you hand pretty good!! Always insure the
cone is centered on the shalf/nut/spinner and have a fair amount
of pressure, if the starter starts to shake pull it away from the prop
and start over..

Have fun

30 minute epoxy AND 5 minute epoxy each take 24 hours to fully cure. The times listed are just the amount of time you have before the stuff "sets". Working time is usually even less (like 12 to 15 minutes for 30 minute epoxy.)

Definitely get help for flying and for the first couple of engine runs. It's much easier to learn when you can hear what a proper run sounds like.

Good luck, have fun, and welcome to RCU!
Dennis-

Neil -- your engine should be run rich, but not "slobbering" rich. When you get it going, open the throttle fully, then slowly close the needle valve and you will hear the engine note start to rise sharply. Stop at that point and back it off until the note starts to drop. Run it like that for 2 - 3 min then shut the motor off & let it cool. Keep doing that until you have run through a couple of tanks of fuel & you will then be good to go.

ABC engines need to be broken in at a rich 2-cycle, & if you have it too rich you will indeed damage it. If you have it too lean you will damage it even faster. Your best bet is to find experienced help.