jcw111

I just acquired a NIB OS 48. It is one of the sweetest running engines I have ever had. Runs and idles like a swiss watch. My question is this: What kind of RPM can I expect running 10% Wildcat fuel with 20% oil and swinging a 11 X 7 or 6 prop. It has only about 2 tanks of fuel run thru it.

Jim Whitney

w8ye

My Feedback: (16)

The OS 52 Surpass  and the Magnum fs 52 carbs are a direct bolt on to the OS 48

w8ye

My Feedback: (16)

The only difference in your head and the head of a OS 52 is that the OS 52 head has the glow plug recessed 2 mm farther down in the head and this is worth 300 rpm to you

jcw111

Thanks for thr reply but my question is what kind of max RPM should I expect ? 7-8 or 9000 I don't want to change anything out carb or head

Jim Whitney

w8ye

My Feedback: (16)

I ran a APC 12 X 5 and was 9500 never ran other props

CrashGaalaas

My Feedback: (8)

I get 11000 rpm with an 11x5 prop. Using CoolPower 10%.

rcdude7

My Feedback: (264)

I don't suppose there is a way of doing this without using a milling machine?

w8ye

My Feedback: (16)

Correct or to buy a OS 52 head which the 48 valves fit and the bore is the same so it is a bolt on swap

jcw111

W8YE  Why would I want an OS 52 carb on the 48? Just curious. The standard carb works very well but does have a small venturi

Jim Whitney

gkamysz

My Feedback: (19)

The standard FS-48 carb is fine even though it's an airbleed type. The FS-52 has a two needle carb.

w8ye

My Feedback: (16)

The Magnum/ASP FS52/61 carb is a direct bolt on also for the OS 48

donkey doctor

Hello; I didn't think that the FS48 carb was an air bleed type, so I dug one out and it isn't. The Surpass 48 carb is a two needle type, not an air bleed type.

gkamysz

My Feedback: (19)

No, the standard FS-48 carb is an airbleed type. If your engine has something else it's been swapped.

jcw111

The OS48 Four Stroke has an airbleed carb.  Mine works like a charm right out of the box. Also It will max out out about 9500 with a 11 X7 MAS prop. So I have answered my original question. Thanks for all the input

Jim