Notices
O.S. Engines Support Ask Bill Baxter your questions about O.S. Engines.

Help needed with pump on OS FS 120

Old 10-27-2006, 02:01 PM
  #1  
cat5752
Thread Starter
My Feedback: (1)
 
cat5752's Avatar
 
Join Date: Aug 2004
Location: La Grande, OR
Posts: 109
Likes: 0
Received 2 Likes on 2 Posts
Default Help needed with pump on OS FS 120

I have recently acquired an OS FS 120 4 stroke w/ pump. On the face of the pump are three fittings. The fittings labeled IN and OUT are no-brainers, but I am not sure what the 3rd one is for. I think it is labeled D (not sure), but what is it's pupose, and does it need to be plugged, vented, or what? I have looked on the OS webpage, but I cannot find a manual for this particular engine. I did find out that it has a shorter prop shaft than the current OS 120 4 strokes, so if you are planning on using Tru-Turn or similar spinners, their normal adapter bolts will not work. If any one knows this information, please let me know. Thanks, Andy
Old 10-27-2006, 03:07 PM
  #2  
bla bla
Senior Member
 
Join Date: Sep 2002
Location: Oslo, NORWAY
Posts: 1,579
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help needed with pump on OS FS 120

I had the classic 1.20 SurpassII with pump.
Could well be the same.

You have the "in and out" nipples at 3.00 & 9.00 oclock. I cant' remember which was which... and then a "third" nipple at say 4.30.

Right. The "in" nipple is fuel in from tank.
The "out" nipple is fuel return to tank. Thats right, a line that goes back to the tank.
The "third" nipple at 4.30 is the line out to carb.
Under the carb on the right hand side there's a connection nipple.
You need a 3cm piece of fuel tube to connect the two.
Old 10-27-2006, 06:53 PM
  #3  
cat5752
Thread Starter
My Feedback: (1)
 
cat5752's Avatar
 
Join Date: Aug 2004
Location: La Grande, OR
Posts: 109
Likes: 0
Received 2 Likes on 2 Posts
Default RE: Help needed with pump on OS FS 120

Hmmmm? That's weird. Do you or anyone else know where I can get a manual for it? The OS webpage only has the OS 120 III listed on it, and it is totally different. Anyway, thanks for the info.
Andy
Old 10-29-2006, 03:46 AM
  #4  
bla bla
Senior Member
 
Join Date: Sep 2002
Location: Oslo, NORWAY
Posts: 1,579
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help needed with pump on OS FS 120

Did what I discribed sound like your pump?
Or do you have a different one?
Old 10-30-2006, 10:44 AM
  #5  
cat5752
Thread Starter
My Feedback: (1)
 
cat5752's Avatar
 
Join Date: Aug 2004
Location: La Grande, OR
Posts: 109
Likes: 0
Received 2 Likes on 2 Posts
Default RE: Help needed with pump on OS FS 120

Yep, there are 3 nipples - #1 IN #2 OUT #3 R. I found an article that says the IN is from the fuel line (clunk) in the tank, the OUT goes to the carb, and the R goes to a third line on the tank, like a vent but instead of angling up, it is angled down to the bottom of the tank. I guess the pump pumps too much fuel, and this is how excess gets back to the tank, instead of dumping it over the side. The vent line on the tank has to be completely vented, no plug, so that the tank doesn't over-pressurize. What is strange here is that when I bought this engine, in between the OUT and the carb, in the fuel line, there is a piece of brass rod with a very small hole drilled in it. I am sure it is a restrictor, but does it restrict pressure or amount (or both)? Thanks for all of your help.
Andy
Old 10-30-2006, 11:11 AM
  #6  
Bax
My Feedback: (11)
 
Join Date: Apr 2002
Location: Monticello, IL
Posts: 19,483
Likes: 0
Received 6 Likes on 5 Posts
Default RE: Help needed with pump on OS FS 120

On the FS-120 Surpass I And II engines, the nipples are this:

"IN"---From fuel tank to pump.
"OUT"---From pump to carburetor
"R"---Return line back to tank

Here's how to adjust your carburetor:

http://www.osengines.com/faq/faq-pumped.html

For the instructions, you can send an email to the address listed below. The FS-120 Surpass I has a large brass screw in the center of the pump. The FS-120 Surpass II has no screw on the pump, but does have a long velocity stack on the carburetor. The carbs are different, so the instructions are different. If you email for the instructions, please let us know which engine you have.
Old 10-30-2006, 02:36 PM
  #7  
bla bla
Senior Member
 
Join Date: Sep 2002
Location: Oslo, NORWAY
Posts: 1,579
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Help needed with pump on OS FS 120

I went to the garage and got ou the ol' SII.
Just go over this again:
Nipple at 3.00 oclock=fuel in (marked in)
Nipple at 4.40 oclock= fuel to carb (marked out)
Nipple at 9.00 oclock = fuel back to tank (not market on mine)

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.