120AX..first impression
01-08-2006, 11:01 PM
#1
Senior Member
Thread Starter
120AX..first impression
Had the opportunity to bench run a fellow club members new 120AX today. It's set up with the OS P-Box muffler/90 degree adapter arrangement. VERY slick installation that would easily fit inside most cowlings of a model designed for this size engine. No leaks, good fuel pressure and reasonably effective muffling. The only caveat is the position of the pressure fitting on the muffler which "could" interfere with your motor mount in the 90 degree muffler position.
Motor starts first time with a bump off of compression. You can just flick the spinner and it'll go. Only ran two tanks through it, but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
Fuel: CP 15% (not my choice...not my motor either).
You don't have to mess with anything. The QC is already done, so all you have to do is fuel it and run it.
Heck yeah I'd buy one. This is a nice motor!
Motor starts first time with a bump off of compression. You can just flick the spinner and it'll go. Only ran two tanks through it, but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
Fuel: CP 15% (not my choice...not my motor either).
You don't have to mess with anything. The QC is already done, so all you have to do is fuel it and run it.
Heck yeah I'd buy one. This is a nice motor!
01-09-2006, 02:17 AM
#2
Senior Member
My Feedback: (4)
Join Date: Jul 2002
Location: Canton,
MI
Posts: 2,914
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
ORIGINAL: RaceCity
but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
01-09-2006, 02:22 AM
#3
RE: 120AX..first impression
Hi!So is it so good!
Of course this 500+ rpm will be reached when the engine will be fully broken in,so don't bother with it.
Also you test run an OS engine,or better an OS 120 AX os's new engine!It is guaranted!
Of course this 500+ rpm will be reached when the engine will be fully broken in,so don't bother with it.
Also you test run an OS engine,or better an OS 120 AX os's new engine!It is guaranted!
01-09-2006, 01:54 PM
#4
Senior Member
Thread Starter
RE: 120AX..first impression
I'm not really sure if 15% fuel is necessary or even desirable with this motor, but it seemed OK on the bench. I think if it were mine I'd go with 5% and see how that worked out. It was 50F here when we ran it. When it's 100F this summer...15% nitro might be a walk on the high side IMO.
01-09-2006, 09:49 PM
#7
Senior Member
My Feedback: (26)
Join Date: Jul 2003
Location: New Richmond,
WI
Posts: 3,518
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
ORIGINAL: RaceCity
Had the opportunity to bench run a fellow club members new 120AX today. It's set up with the OS P-Box muffler/90 degree adapter arrangement. VERY slick installation that would easily fit inside most cowlings of a model designed for this size engine. No leaks, good fuel pressure and reasonably effective muffling. The only caveat is the position of the pressure fitting on the muffler which "could" interfere with your motor mount in the 90 degree muffler position.
Motor starts first time with a bump off of compression. You can just flick the spinner and it'll go. Only ran two tanks through it, but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
Fuel: CP 15% (not my choice...not my motor either).
You don't have to mess with anything. The QC is already done, so all you have to do is fuel it and run it.
Heck yeah I'd buy one. This is a nice motor!
Had the opportunity to bench run a fellow club members new 120AX today. It's set up with the OS P-Box muffler/90 degree adapter arrangement. VERY slick installation that would easily fit inside most cowlings of a model designed for this size engine. No leaks, good fuel pressure and reasonably effective muffling. The only caveat is the position of the pressure fitting on the muffler which "could" interfere with your motor mount in the 90 degree muffler position.
Motor starts first time with a bump off of compression. You can just flick the spinner and it'll go. Only ran two tanks through it, but at the 2-4 cycle break it's turning an APC 16-8 at 9000rpm. I believe the motor is spec'd to turn this prop at around 9500rpm, so after a bit more running time, and some more leaning of the needle...I think it'll be right on the money.
Fuel: CP 15% (not my choice...not my motor either).
You don't have to mess with anything. The QC is already done, so all you have to do is fuel it and run it.
Heck yeah I'd buy one. This is a nice motor!
01-10-2006, 06:45 AM
#8
Senior Member
My Feedback: (15)
Join Date: Sep 2004
Location: Pickerington,
OH
Posts: 664
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
The Tower web-site says you should run 20% oil in this engine. What does the O.S. manual say? I know of very few fuels that have 20% oil. What fuel do you guys plan to run?
01-10-2006, 08:12 AM
#9
Senior Member
My Feedback: (5)
Join Date: Mar 2004
Location: Halifax,
NS, CANADA
Posts: 1,848
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
ORIGINAL: PropSpinner
The Tower web-site says you should run 20% oil in this engine. What does the O.S. manual say? I know of very few fuels that have 20% oil. What fuel do you guys plan to run?
The Tower web-site says you should run 20% oil in this engine. What does the O.S. manual say? I know of very few fuels that have 20% oil. What fuel do you guys plan to run?
I take the 20% oil to heart on every glow engine ( about 12 ) that I own. I use CP and add 4 ozs. ( per gal. ) of Klotz oil ( gives me about 20% oil ).
01-10-2006, 09:34 AM
#10
Senior Member
Thread Starter
RE: 120AX..first impression
Well...instructions make lots of recommendations that nobody pays any attention to. In this case...I'm only the run-in guy.
Somebody else owns the motor, and what he chooses to do is his deal. I've made some suggestions, and that's all I can do...the ball is in his court now.
PS: I like 20% oil too, but it would seem that many people are trying economize on paper towels and Windex by using less oil. <GGG>
Somebody else owns the motor, and what he chooses to do is his deal. I've made some suggestions, and that's all I can do...the ball is in his court now.
PS: I like 20% oil too, but it would seem that many people are trying economize on paper towels and Windex by using less oil. <GGG>
01-10-2006, 09:57 AM
#11
My Feedback: (102)
Join Date: Dec 2001
Location: Colonial Beach, VA
Posts: 20,370
Likes: 0
Received 25 Likes
on
25 Posts
RE: 120AX..first impression
Prop, you can get 20% lube fuel from Fox MFG. in either 50/50 syn/castor blend or all castor and your choice of nitro %. Most of the time they have some in stock but will make it for you, they do not make fuel on certain days when the humidity is high. I've been using the 5% fox fuel since 1991 and only had to wait a week once. As far as I'm concerned it is the best two stroke fuel, bar none.
01-10-2006, 10:30 AM
#12
RE: 120AX..first impression
Sig Champion fuel is 20% oil and is normally 50% castor 50% Klotz. They also make both a 20% all castor and a 25% all castor fuel in 5% and 10% nitro blends.
01-10-2006, 11:18 AM
#14
Senior Member
Thread Starter
RE: 120AX..first impression
Yeah...that'd probably be fine. Byrons mixes their fuel by weight, so "20% oil" actually comes out to be a bit less than the standard "volumetric" measurement used. I'm sure somebody can calculate the actual percentage to 40 places....
One thing...I'm not so sure this motor needs 15% nitro. It's OK on the bench...lightly loaded, and richer than snot on a cold day. I'm thinking more along the lines of what the motor will think of that on a hot day...with a log propeller on it....leaned out til the needle strips. IMO.....5% would be more than enough....10% at the outside. Call it a hunch.
One thing...I'm not so sure this motor needs 15% nitro. It's OK on the bench...lightly loaded, and richer than snot on a cold day. I'm thinking more along the lines of what the motor will think of that on a hot day...with a log propeller on it....leaned out til the needle strips. IMO.....5% would be more than enough....10% at the outside. Call it a hunch.
01-10-2006, 11:44 AM
#15
RE: 120AX..first impression
I think I'll break it in on some Byrons 10% Nitro and see how it goes.
ORIGINAL: RaceCity
Yeah...that'd probably be fine. Byrons mixes their fuel by weight, so "20% oil" actually comes out to be a bit less than the standard "volumetric" measurement used. I'm sure somebody can calculate the actual percentage to 40 places....
One thing...I'm not so sure this motor needs 15% nitro. It's OK on the bench...lightly loaded, and richer than snot on a cold day. I'm thinking more along the lines of what the motor will think of that on a hot day...with a log propeller on it....leaned out til the needle strips. IMO.....5% would be more than enough....10% at the outside. Call it a hunch.
Yeah...that'd probably be fine. Byrons mixes their fuel by weight, so "20% oil" actually comes out to be a bit less than the standard "volumetric" measurement used. I'm sure somebody can calculate the actual percentage to 40 places....
One thing...I'm not so sure this motor needs 15% nitro. It's OK on the bench...lightly loaded, and richer than snot on a cold day. I'm thinking more along the lines of what the motor will think of that on a hot day...with a log propeller on it....leaned out til the needle strips. IMO.....5% would be more than enough....10% at the outside. Call it a hunch.
01-11-2006, 11:16 AM
#16
My Feedback: (14)
Join Date: May 2002
Location: Gales Ferry, CT
Posts: 4,878
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
A friend just bought this engine, it sure is purdy, and light! The cylinder fins are very well cast and very fine, about the thinnest cross section I have ever seen.
I'm looking forward to running it.
I'm looking forward to running it.
01-11-2006, 06:47 PM
#17
Senior Member
My Feedback: (15)
Join Date: Sep 2004
Location: Pickerington,
OH
Posts: 664
Likes: 0
Received 0 Likes
on
0 Posts
RE: 120AX..first impression
Thanks for the fuel information guys. I've dabbled in this hobby off and on since about 1970 an have not always had the benefit of belonging to a club and the bank of knowledge that it provides. I've never owned anything larger than a O.S. 46 and only O.S. engines until recently. The O.S. brand is almost idiot proof and I've always had good luck running whatever plugs and fuel the LHS had. I recently started purchasing larger engines and other brands and I'm finding out what a huge difference in performance fuel and plugs make. I've also found that you really need to read those manuals that come with the engine and the recommendations that are in them. They are at the least a good starting point and can save you a lot of tinkering. I really have found RCU to be so useful at gathering good information and dispelling some of the myths that people spout.
If I purchase this engine I plan to run 20% oil and 5% nitro at break-in to see how it runs. If it doesn't perform I'll bump the nitro content. Thanks again.
If I purchase this engine I plan to run 20% oil and 5% nitro at break-in to see how it runs. If it doesn't perform I'll bump the nitro content. Thanks again.
