Clicking on OS FS 120 Surpass II Pumped
06-22-2005, 06:42 PM
#1
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Clicking on OS FS 120 Surpass II Pumped
I have been out of the hobby for some year (since 1985), and about 3 years ago while thinking of building a plane and getting back in I bought a used OS FS 120 Surpass II pumped from ebay.
Well, I finally have built a plane (a Sig Mayhem) and flew it this past weekend. However, I think I may have something wrong with my engine.
I did have some problem this past weekend because the engine is inverted and the fuel tank is higher than the needle valve which caused siphoning while it was just sitting on the ground. Also, when I first started it, I had the wrong size prop on it and it revved for about a minute up to 12,000RPM (with a 14-4).
We installed a 15-6 Dynathrust and the RPM's dropped to 9800 and we flew a flight with it.
Now, yesterday, I worked on it to install a metal spinner and as I was turning the shaft, I noticed what sounds like a 'clicking' coming from inside when the prop is somewhere between compression points. It is not difficult to hear and does not sound right. It wasn't making this noise before I started the engine.
Before starting the engine, I had checked the valve clearance with the included gauges and adjusted them to be right on. The only thing bad I notice (again, before running the engine) was that when I removed the valve cover, one of the pushrods was off of the rocker arm. I loosened the rocker arm, put the pushrod back in place, and adjusted the valve clearance. I had added afterrun to the engine back when i got it 3 years ago, and it has been inside the house since.
Can anyone give me some advice about what I should do to check out this clicking noise. I hate to tear down the whole engine unless it is necessary. Any tips/advice appreciated.
thanks, Steve
Well, I finally have built a plane (a Sig Mayhem) and flew it this past weekend. However, I think I may have something wrong with my engine.
I did have some problem this past weekend because the engine is inverted and the fuel tank is higher than the needle valve which caused siphoning while it was just sitting on the ground. Also, when I first started it, I had the wrong size prop on it and it revved for about a minute up to 12,000RPM (with a 14-4).
We installed a 15-6 Dynathrust and the RPM's dropped to 9800 and we flew a flight with it.
Now, yesterday, I worked on it to install a metal spinner and as I was turning the shaft, I noticed what sounds like a 'clicking' coming from inside when the prop is somewhere between compression points. It is not difficult to hear and does not sound right. It wasn't making this noise before I started the engine.
Before starting the engine, I had checked the valve clearance with the included gauges and adjusted them to be right on. The only thing bad I notice (again, before running the engine) was that when I removed the valve cover, one of the pushrods was off of the rocker arm. I loosened the rocker arm, put the pushrod back in place, and adjusted the valve clearance. I had added afterrun to the engine back when i got it 3 years ago, and it has been inside the house since.
Can anyone give me some advice about what I should do to check out this clicking noise. I hate to tear down the whole engine unless it is necessary. Any tips/advice appreciated.
thanks, Steve
06-23-2005, 01:18 PM
#2
My Feedback: (11)
RE: Clicking on OS FS 120 Surpass II Pumped
We normally use an APC 15 x 8 prop as our test standard. If the FS-120 Surpass will turn in the mid-9,000's or higher, it's considered "good". We've seen Master Airscrew 15 x 8 props turn about 10,100. The difference can be accounted for by blade profile and airfoil.
A brief run at 12K RPM won't hurt the engine. If it's running fine afterwards, then you had no damage.
If the fuel level in the tank is higher than the needle, and the fuel lines are full, then some fuel will siphon out and drip from the carb. This can't be avoided unless the fuel line loops higher than the tank and is empty, or you clamp the line.
Clicking when a four-stroke engine is turned over is normal. You'll hear it more in larger engines than the smaller ones, but you'll still hear it. As long as you're using a good-quality fuel and keep the rocker arm/valve clearances correct, you'll have no problems. At high speeds, the clicking becomes the buzz you normally hear coming from the top of four-stroke engines.
A brief run at 12K RPM won't hurt the engine. If it's running fine afterwards, then you had no damage.
If the fuel level in the tank is higher than the needle, and the fuel lines are full, then some fuel will siphon out and drip from the carb. This can't be avoided unless the fuel line loops higher than the tank and is empty, or you clamp the line.
Clicking when a four-stroke engine is turned over is normal. You'll hear it more in larger engines than the smaller ones, but you'll still hear it. As long as you're using a good-quality fuel and keep the rocker arm/valve clearances correct, you'll have no problems. At high speeds, the clicking becomes the buzz you normally hear coming from the top of four-stroke engines.
