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

OS FS-91SII pump question

Old 06-23-2019, 06:06 AM
  #1  
ahdofu
Thread Starter
 
Join Date: Jul 2003
Location: Bellevue, WA
Posts: 36
Received 0 Likes on 0 Posts
Default OS FS-91SII pump question

I have had my surpass pump engine for a while. This year I had to replace the pump as well as the regulator's valve cover as they were both leaking. What I have noticed is that the engine RPM at high end is independent of the needle screw position! More specifically I can leave the needle screw anywhere from 4 full turns down to one turn (away from fully closed) and the engine RPM hardly changes! The range that I see is 8800-9050 RPM on a MA14x6 prop and using Powermaster 15/18 fuel. Prior to the changes the ideal setting for the needle was at a full turn and I think I was getting more than 9500 RPM. It certainly was sensitive to the needle position. Has anyone come across something like this before?
Thanks

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 - Manage Preferences - 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.