O.S. GF40 40cc Four Stroke Gasser ( Part #2)
04-18-2014, 07:05 AM
#26
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Soft mounting smaller gassies is fairly straight forward. "Soft mounting" means installing the engine on rubber isolation. The rubber is then attached to the firewall.
I have a thread here in RCU that describes how one type of soft mount is made that will accept stand offs. The mount is essentially two plywood discs with balsa spacers in each. The discs are connected to one another via a rubber band glued to the outside perimeter. The discs float against each other, one disc secured to the engine and the other against the FW
04-18-2014, 03:08 PM
#27
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What are the specs on the Evolution oil you are using?
The first batches of evolution oil were actually Mobil 1 which is good stuff. More recent batches of evolution oil are totally different. Its blue in color and i suspect is morgans coolpower.
Nearly all 2-stroke oils are designed for just that, 2-strokes. They are not designed to lubricate valve trains and they tend to evaporate or varnish up on the exhaust valves because gas burns hotter than glow.
Try the Stihl HP Ultra, for 2 reasons.
Stihl make 4-stroke pre-mix engines similar to our model engines and the ultra is the oil that they specify in those engines.
It has the highest flashpoint of any 2-stroke oil i have found. Its not going to evaporate or varnish as quickly as other oils.
There are hundreds of anecdotal reports from happy Stihl ultra users getting good results.
Lastly 20:1 is not necessary in the OS. It had needle bearings on the conrod so 32:1 is fine. Saitos need 20:1 due to their bushed conrods.
The first batches of evolution oil were actually Mobil 1 which is good stuff. More recent batches of evolution oil are totally different. Its blue in color and i suspect is morgans coolpower.
Nearly all 2-stroke oils are designed for just that, 2-strokes. They are not designed to lubricate valve trains and they tend to evaporate or varnish up on the exhaust valves because gas burns hotter than glow.
Try the Stihl HP Ultra, for 2 reasons.
Stihl make 4-stroke pre-mix engines similar to our model engines and the ultra is the oil that they specify in those engines.
It has the highest flashpoint of any 2-stroke oil i have found. Its not going to evaporate or varnish as quickly as other oils.
There are hundreds of anecdotal reports from happy Stihl ultra users getting good results.
Lastly 20:1 is not necessary in the OS. It had needle bearings on the conrod so 32:1 is fine. Saitos need 20:1 due to their bushed conrods.
04-18-2014, 07:19 PM
#28
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Karl,
Soft mounting smaller gassies is fairly straight forward. "Soft mounting" means installing the engine on rubber isolation. The rubber is then attached to the firewall.
I have a thread here in RCU that describes how one type of soft mount is made that will accept stand offs. The mount is essentially two plywood discs with balsa spacers in each. The discs are connected to one another via a rubber band glued to the outside perimeter. The discs float against each other, one disc secured to the engine and the other against the FW
Soft mounting smaller gassies is fairly straight forward. "Soft mounting" means installing the engine on rubber isolation. The rubber is then attached to the firewall.
I have a thread here in RCU that describes how one type of soft mount is made that will accept stand offs. The mount is essentially two plywood discs with balsa spacers in each. The discs are connected to one another via a rubber band glued to the outside perimeter. The discs float against each other, one disc secured to the engine and the other against the FW
Thank you for the information, I will attempt to do the same with mine.
Regards,Karl.
04-19-2014, 09:12 PM
#29
Senior Member
The key thing that I've discovered is the best way to hold the rubber on. We tend to use motorcycle inner tubes size about 1/4 -3/8" smaller diameter than the disc diameter. The rubber bands are cut with a sharp xacto and a straight edge. The rubber is thoroughly cleaned with soap and water then cleaned further with alcohol. Roughing up the rubber with a Dremel drum sander exposes fresh rubber and enables regular ca to glue the rubber to the plywood. I don't use the thickened black ca glue. Medium and thin is all that's needed.to build the whole mount. Good luck with yours. Let me tell you it definitely removes the high freq vibes from entering and destroying your airframe and radio gear.. There is some low freq shake at idle but that's not destructive
04-21-2014, 03:17 AM
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05-24-2014, 06:14 AM
#32
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Setting engine up cylinder and running for over 15 min at high RPM with 18x8 prop or less will give you that effect.
Using bigger prop (lowering RPM) and setting engine down cylinder helped me to avoid issue.
Using bigger prop (lowering RPM) and setting engine down cylinder helped me to avoid issue.
05-24-2014, 06:27 AM
#33
Ok Thanks Akouzmit
I know the Saito Fg-40 does not have this issue but it features connecting rod that does not have neelde bearing unlike the OS GF 40. The OS said to run smoother, too, but who knows?
I know the Saito Fg-40 does not have this issue but it features connecting rod that does not have neelde bearing unlike the OS GF 40. The OS said to run smoother, too, but who knows?
05-24-2014, 06:37 AM
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the best engine I have ever had in 4-stroke departmend despite missing needle bearings :-)
I love OS as it is much lighter compare to Saito gf40.
05-24-2014, 07:13 AM
#35
05-24-2014, 09:21 AM
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They both running very smooth with stock mufler.
I would advice to load them with larger prop in order to reduce max RPM down to 7000-8000 range at the ground.
lubrication is better in such condition especially for OS as it has metal ball went, which has quite insertion at high RPM and doesn't work well at high RPM passing much of the oil out instead of passing it all to the top of the engine for rockers lubrication.
I do not see such problem on any my Saito engines: 14c, 17, 21, 30, and 36. They all running super well and starting on the first flip if primed. They also keep very low idle RPM from the start when engine is cold to the end of the flight.
Carbs initially set a bit rich and after ~7 20 min flight you may reduce high needle a bit down.
Watch for air bubbles as these 4-stroke gassers are VERY sensitive to even tiny air bubbles.
I would advice to load them with larger prop in order to reduce max RPM down to 7000-8000 range at the ground.
lubrication is better in such condition especially for OS as it has metal ball went, which has quite insertion at high RPM and doesn't work well at high RPM passing much of the oil out instead of passing it all to the top of the engine for rockers lubrication.
I do not see such problem on any my Saito engines: 14c, 17, 21, 30, and 36. They all running super well and starting on the first flip if primed. They also keep very low idle RPM from the start when engine is cold to the end of the flight.
Carbs initially set a bit rich and after ~7 20 min flight you may reduce high needle a bit down.
Watch for air bubbles as these 4-stroke gassers are VERY sensitive to even tiny air bubbles.
05-25-2014, 01:19 AM
#37
They both running very smooth with stock mufler.
I would advice to load them with larger prop in order to reduce max RPM down to 7000-8000 range at the ground.
lubrication is better in such condition especially for OS as it has metal ball went, which has quite insertion at high RPM and doesn't work well at high RPM passing much of the oil out instead of passing it all to the top of the engine for rockers lubrication.
I do not see such problem on any my Saito engines: 14c, 17, 21, 30, and 36. They all running super well and starting on the first flip if primed. They also keep very low idle RPM from the start when engine is cold to the end of the flight.
Carbs initially set a bit rich and after ~7 20 min flight you may reduce high needle a bit down.
Watch for air bubbles as these 4-stroke gassers are VERY sensitive to even tiny air bubbles.
I would advice to load them with larger prop in order to reduce max RPM down to 7000-8000 range at the ground.
lubrication is better in such condition especially for OS as it has metal ball went, which has quite insertion at high RPM and doesn't work well at high RPM passing much of the oil out instead of passing it all to the top of the engine for rockers lubrication.
I do not see such problem on any my Saito engines: 14c, 17, 21, 30, and 36. They all running super well and starting on the first flip if primed. They also keep very low idle RPM from the start when engine is cold to the end of the flight.
Carbs initially set a bit rich and after ~7 20 min flight you may reduce high needle a bit down.
Watch for air bubbles as these 4-stroke gassers are VERY sensitive to even tiny air bubbles.
http://www.worldhobbies.com
05-25-2014, 09:23 AM
#38
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In Canada 1 year ago I have paid $800. US
The price on the web you provided looks very attractive $510 US
if it is not from black market then go for it.
In US it is still $800 US at reputated stores.
The price on the web you provided looks very attractive $510 US
if it is not from black market then go for it.
In US it is still $800 US at reputated stores.
05-25-2014, 09:58 AM
#39
I'm also a bit confused on such a big difference on prices? Tower Hobbies lists it at 800$.
05-25-2014, 08:47 PM
#40
Senior Member
OS engines from black market ?
it doesn't seem to be a fake site their phone number is there.
anyway the US distributor is the most expensive on earth.
if you wanna get support in USA you have to buy from them that's why they f*** americans and canadians.
http://www.osengines.gr/index.php?ma...3f1a667dddad28
it doesn't seem to be a fake site their phone number is there.
anyway the US distributor is the most expensive on earth.
if you wanna get support in USA you have to buy from them that's why they f*** americans and canadians.
http://www.osengines.gr/index.php?ma...3f1a667dddad28
Last edited by Mikola; 05-25-2014 at 08:54 PM.
05-25-2014, 09:29 PM
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I just saw your location !!! Pretty funny although some here may disagree . You wouldnt want to get behind my sister unless you had a peg on your nose > Cheers
05-27-2014, 08:54 PM
#42
I second the suggestion to run Stihl HP Ultra oil! It's the only oil I use in all my engines, 2 or 4 stroke.
Try it, it does'nt coke the inside of the crankcase like others.
Mark.
Try it, it does'nt coke the inside of the crankcase like others.
Mark.
