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

OS 91 surpass making a strange popping sound.

Old 08-28-2015, 08:06 PM
Thread Starter
My Feedback: (57)
twinster2's Avatar
Join Date: Jan 2002
Location: Kalamazoo, MI
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default OS 91 surpass making a strange popping sound.

This may sound weird, but I have a new but old OS 91-fs Surpass engine on my Topflite AT-6 that makes a popping sound from the exhaust as it flies past. You can not hear it as it approaches, but once it flies past it is very audible. The engine has about 2 hours on it and has made this noise from the beginning. Maybe popping is the wrong word, it could actually be missing. Anyway, I have tried different plugs and fuels with not change. Could this be a valve clearance or timing issue?
Old 08-31-2015, 06:26 AM
My Feedback: (11)
Join Date: Apr 2002
Location: Monticello, IL
Posts: 19,483
Likes: 0
Received 6 Likes on 5 Posts

If the engine is running well, we'd ignore random noises. Especially if the engine's at less than full throttle. You may be hearing the occasional misfire when at reduced throttle settings that have the sound amplified a bit by the exhaust system.

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.