I am trying to get my EF Yak back up and flying for sunday and am trying to get it all put together tonight so, all I have to do is run it tomorrow..

The Perry instructions say not to run the muffler pressure line back to the tank.. What am I supposed to do with the muffler pressure line coming from the tank? I can't completely block it off because then I won't be able to fuel it... So i'm guessing i just need to run the tubing out the bottom and unplug it when fueling and then plug it back up when flying? It also says to make sure the tank has plenty of ventilation... Confused much....

Yes I am running a OS 1.60

OK.. cap off the muffler pressure... you can also try to use the muffler pressure... yes.. with the pump,, try it first without the muff-press though... leave the vent line open to the tank.
I have over 300 flights on an OS 160 with perry pump... where did you tap the crank for the pump pressure line???
I had the best results doing the following...
The instructions say the needle should be at something like 3 turns out.. I could not get that to work... I maximized the pump pressure/volume (Turn the little allen set screw to max pump-action).. and then I had the main needle at about 7/8 of a turn.. yes.. just under one full turn.. the low end needed just a very minute adjustment.. I can't remember if it needed lean or rich.. but just 1/32 of a turn... with an APC 18 x 6 wide prop.. it was a great running motor...
To start, plug the carb with your thumb and turn over 5 times at full throttle... then set carb to idle and put on the glow driver and snap the spinner backwards with your fingers and it will prolly start.

OS160 and a Perry pump.. awesome combo!

(Though I was using a pitts muff with a little less back pressure then the std muff)

Ok.

I tapped the pressure tap in the backplate, not in the center but off to the side a little bit. I just received my Perry Pump today along with a Slimline Pitts muffler, I broke in and ran the engine with a Bisson pitts muffler. When I was flying the plane trying to figure out why the heck it would always die for no reason, one of the muffler stacks broke off, I didn't like the big ol heavy bulky muffler anyways so I replaced it with a Slimline.

My Perry Pump is mounted, the breather hole is on the top, it said in the instructions to try and make sure it stays pointed to the ground but I would have to mount the pump in a funny fashion to get it to work, it would involve having alot more fuel tubing and longer pressure tubing. I only decided to mount it with the breather hole on the top because I have searched multiple pictures and have seen alot of people mounting it with the breather hole on the top. so I hope its not to critical...

So, I guess I'll just run a breather line from the tank down to the bottom of the cowl and leave it unplugged and cap off the pressure taps on the muffler.

Thanks!

The vent line is just that, a vent line, run it outside and when you are fueling the fuel will come out. DO NOT PLUG the vent line. The tank must be vented for the "pump' to pull fuel from the tank and regulate properly.

Secondly, you never add pressure to a a tank when you are using a "regulated" pump, like the perry pump. It will not regulate the fuel delivery properly if you add pressure.

The directions with the pump are very explicit about how to adjust the regulation on the pump.

I don't know if you got your answer before this, I hope this helps.

I have an OS 160 with well over 400 flights and no pump. I would agree the tank location (height to carburator) can be detromental to the ability of the engine to draw fuel.

I

Do they have a Perry Pump for smaller engines like the OS 46ax? I'm issues with my 50 size Kyosho FW 190 that has the motor inverted. The carb is low in relation to the tank and causes flooding and rapid rpm changes in flight. Rather than remount the engine, I have heard that a fuel pump would fix this. Any ideas?

I have my own question about the perry pumps and 4 stroke engines.

I picked up and Extra 260 with an OS 4 stroke engine(second hand)...this is my first go around with model 4 strokes engines. The plane was never flown, but the engine has been run on other planes.

OS FS 120 Surpass 4 stroke with built in fuel pump...this is an older version of the engine and not the Surpass III like on Towers site. The fuel pump was bad, so they put a Perry pump on it. The engine has good compression.

I don't know much about the perry pumps, but they had a pressure line run from the muffler to the bottom of the perry pump(pressure nipple). From what I gather here on the forums...the muffler pressure is not enough to run the perry pump???

Tapping the case for a pressure line?!?!?!?!?. The built in fuel pump is not really removable(there would be holes left in the back plate). What can I do to fix my issues??

Thanks in advance

Originally Posted by superstocktx

I have my own question about the perry pumps and 4 stroke engines.

I picked up and Extra 260 with an OS 4 stroke engine(second hand)...this is my first go around with model 4 strokes engines. The plane was never flown, but the engine has been run on other planes.

OS FS 120 Surpass 4 stroke with built in fuel pump...this is an older version of the engine and not the Surpass III like on Towers site. The fuel pump was bad, so they put a Perry pump on it. The engine has good compression.

I don't know much about the perry pumps, but they had a pressure line run from the muffler to the bottom of the perry pump(pressure nipple). From what I gather here on the forums...the muffler pressure is not enough to run the perry pump???

Tapping the case for a pressure line?!?!?!?!?. The built in fuel pump is not really removable(there would be holes left in the back plate). What can I do to fix my issues??

Thanks in advance

Order a replacement back cover for the engine ( non- pumped version ) and tap that. Muffler pressure isn't enough to run your pump. ( or tap through the mounting beam on the side of the engine )
Does the carb have only one line going to it from the pump? If so, you can probably make it work, but if it has two lines ( one being a return ) the you'll need to get a new carb as well as back plate and then you can omit the pump all together.
By that I mean turn it into a non-pumped engine.

Luck, Dewayne

Originally Posted by Dewayne Vaughn

Order a replacement back cover for the engine ( non- pumped version ) and tap that. Muffler pressure isn't enough to run your pump. ( or tap through the mounting beam on the side of the engine )
Does the carb have only one line going to it from the pump? If so, you can probably make it work, but if it has two lines ( one being a return ) the you'll need to get a new carb as well as back plate and then you can omit the pump all together.
By that I mean turn it into a non-pumped engine.

Luck, Dewayne

Thanks for the info Dewayne. Yes the carb only has one line going to it. I ordered a new backplate(non pump), hopefully it will work on this older version I have, I think it will. Another question I have is: there is a line that runs from the front of the crankcase(tapped) to the intake manifold...what is the purpose of that line?...Thanks in advance..

Dennis
President, Rolla Modelers Assoc.

Dennis, thats the crankcase vent. better for the enviroment.... blah blah blah....
It also greatly helps the cam get oiled. ( very important )
I just noticed that your in Rolla!!!
My son lives there, graduates this year. He's coming for christmas.

Much luck, Dewayne

Dewayne, Thanks again for the info. Your son must go to MST then. It's a great school to attend. I'll get these 4 strokes figured out. I have the gas and nitro down pat tho. I like the torque of the 4 strokes. Oh...If your son flies planes also, you should have him look the Rolla Molelers Assoc. up. We have a nice field to fly at.

Having owned the engine your dealing with, It's easy for me to tell you about it.
I swung a graupner 14X10 on an 80" hooker at 9.5 lbs and it was great.
Today, I'd use an apc 14X8 or 15X7....something close to that ( I like the narrow props, I get more rpms and the flywheel effect is still there ) I used 10% nitro.
Tank was on the C.G. cause you can do that with a pumped engine...
I love pumpers!!!

Originally Posted by Dewayne Vaughn

Having owned the engine your dealing with, It's easy for me to tell you about it.
I swung a graupner 14X10 on an 80" hooker at 9.5 lbs and it was great.
Today, I'd use an apc 14X8 or 15X7....something close to that ( I like the narrow props, I get more rpms and the flywheel effect is still there ) I used 10% nitro.
Tank was on the C.G. cause you can do that with a pumped engine...
I love pumpers!!!

I'm Gonna sling a 15x8 wood on there. I wanted a Mejzlik prop for it, but they don't make one that small, I think. The Mejzlik props are nice, but pricey!!!. 22x8 Mejzlik works great on my 30% Yak 54 with a Sachs/Dolmar EI 50cc gaser. Thanks a bunch for the info on the 4 strokes. You know anyone that would be interested in a Bert Rutan "quickie", 55" winspan, built, never flown. I'm selling as an ARF. Cheap!!!!

Thank you for your help I posted a new thread because it is technically a different topic, two different programs... but that is beside the point. I appreciate your help, and I will probably ask the sales dept. and see if they have a definitive answer on this. I really do enjoy this webhost though Thanks again