OS 110 4 stroke acting funny???
05-20-2012, 05:31 PM
#1
Senior Member
Thread Starter
Join Date: Nov 2009
Location: Marion,
IA
Posts: 1,151
Likes: 0
Received 0 Likes
on
0 Posts
OS 110 4 stroke acting funny???
Hello. I just bought a new OS 110 four stroke, I did the break in according to manual, and now I am just testing props. I so far have only ran it with a 14x8.
One think that I'm worried about is what happens in the air at full throttle, and on the ground,I run the engine up to full RPM, and back off about 200-300 RPM, like I always have done.
I took off, and did a high speed pass, full throttle, and the engine started changing RPMS really fast and running like it was out of control. It wasn't running rich, I know that, but not staying a steady RPM, it gains RPM, then quickly comes back to normal. Its hard to explain, but it just runs really odd, and never had that happen before with all my 4 strokes (all 8 of them).
So, what could be the problem? I replaced fuel line, and checked everything with the fuel and it seems to be fine. I was thinking maybe the engine is sucking air and leaning out for just a second than sucking more fuel? I'm not sure. It has probably 7 tanks of fuel through it. Maybe overheating? I have large holes cut in the cowl, so I don't think thatsa problem. I brought the airplane down, and richened it about 400 RPM from full, and it still had the same problem.
I don't want to damage the engine, so I want to get the problem fixed.
Any help is appreciated!
Thanks
Jason
One think that I'm worried about is what happens in the air at full throttle, and on the ground,I run the engine up to full RPM, and back off about 200-300 RPM, like I always have done.
I took off, and did a high speed pass, full throttle, and the engine started changing RPMS really fast and running like it was out of control. It wasn't running rich, I know that, but not staying a steady RPM, it gains RPM, then quickly comes back to normal. Its hard to explain, but it just runs really odd, and never had that happen before with all my 4 strokes (all 8 of them).
So, what could be the problem? I replaced fuel line, and checked everything with the fuel and it seems to be fine. I was thinking maybe the engine is sucking air and leaning out for just a second than sucking more fuel? I'm not sure. It has probably 7 tanks of fuel through it. Maybe overheating? I have large holes cut in the cowl, so I don't think thatsa problem. I brought the airplane down, and richened it about 400 RPM from full, and it still had the same problem.
I don't want to damage the engine, so I want to get the problem fixed.
Any help is appreciated!
Thanks
Jason
05-20-2012, 06:07 PM
#2
Senior Member
RE: OS 110 4 stroke acting funny???
Is this your Extra 300S? Maybe the prop is cavitating and therefore spinning up extremely fast. Is there also a problem of valve float when spinning that fast? Just wondering if these engines (RC 4-stroke in general) are interference engines - the valves will hit the piston if the valve timing is off.
What 14x8 prop are you using?
What 14x8 prop are you using?
05-20-2012, 07:01 PM
#3
My Feedback: (-1)
RE: OS 110 4 stroke acting funny???
I tach my engines up to there max and back off about 400 rpms. I don't have the os 1.10, it's there new model, I have a couple of the .91s and 1.20s. I run 14 to 15 inch APC props on the .91s and get no surging from them. It could be the prop or fuel flow, I would also check the valve adjustment but the most important thing, I would go into the glow engine forum, then go into Factory Support and ask my own Go To Guy, Bill Baxter. If I have any odd problems with any of my OS engines I ask Bax. I'm guessing, he knows a lot more about them then me.
