All,
I have read numorous posts on the OS 160. From these recomendations I am usind a perry pump, Wildcat 15% fuel, Bisson Pitts, Mezhlic 18x6 carbon fiber prop. The plane has a 17oz tank located over the CG. I am having extreme difficultity starting/setting/breaking in this engine. It seems that the Perry pump gives too much fuel I have prrbleme getting the engine to run even with the needle only open 1 turn. I have replace the perry pump with a new one but have the same result. I should have broken this engine in on the test stand, but hind sight is 20-20.

Can somebody give me suggestions on how to approach starting, breaking in, and setting this engine to make it extremly reliable for the maden flight. Any suggestions would be appriciated

Simple, remove the Perry pump, block-off one of the exhaust outlets on the BCM muffler(to increase muffler pressure) and place the tank behind the firewall. I had this exact setup for over 100 flights on a 1/4 scale GP Giles 202 with no dead sticks or running probs. Run two tanks VERY rich on the ground, set the main NV about 500 rpm off peak for the first 2 or 3 flights and have fun.

If your 160 doesn't run set up as above, you have a fuel delivery or air leak problem somewhere. And, oh, don't listen to anyone that says that closing off one exhaust outlet causes problems. Me and another guy at the club have been running our big 2-strokes like this for a while w/ no performance or overheating problems.

With the pump you will need to lean the low end WAY in. I had to turn mine in at least one full turn. You can also adjust the pump, but I never had to do that.

I had the similar problems with mine! I tuned the top end! I had to turn the screw in on the pump to get it to feed enough fuel to keep the top end from leaning out! Then the bottom end was to rich so I had to adjust the low end screw on the OS 160 By at least one full turn till the bottom end leaned out! It runs PUUURRRFFEEECT
Now!
http://www.rcuniverse.com/forum/m_10...tm.htm#1079493

15% fuel is not a good idea for this engine from what I have experienced. These engines run best on 5% or 0% nitro, higher is simply wasting money and usually results in a mid range knock/clatter that will not adjust out.

Try some Omegs 5% and see if you don't see an immediate improvement in ease of tuning and in smoothness.

Hi!
Yes!
5% nitro is all it need! Why waste more money on nitro when it is just not needed?
Regards!
Jan K

I use 15% wildcat to keep things simple, It also works great in my 4 strokes, but with this gas guzzler I may step down a little for economy. I think I may have figured out my problems:

Problem 1, The glow plug was glowing, but the lower 1.5 turns of the glowing element did not glow I grabed a new plug and It glowed much brighter, posible the ritch attempts of running this engine partually fouled the plug.

Problem 2, Extremly too rich all ranges. I turned the low speed in 1 turn, then once I got the engine started I slowly advanced throttle then kept squeezint the fuel line and turning in the HS needle until it would run at full throttle. The manual recomments to start with a needle valve setting of 2.5 turns, this engine runs rich at .75 turns. I ran three tanks through the engine cycling between 4-strokin and 2-strokin. I plan to run three more tanks through it then try and adjust the low and high in for reliable Idle, smooth transition, and high end 400-500 off peak. Wish me luck.

I want this engine to be fully broken in before I fly I have a way to much time and money in this plane to rush the maden.

Thanks for all your help

dn, a Cline regulator would solve this problem instantly. I am running four of them now, they are no brainers to set up and give complete peace of mind.

here is a pic

hobbsy,
I was considering the Cline until my limited sucess last night