Go Back  RCU Forums > RC Airplanes > Questions and Answers
Reload this Page >

My repaired OS engine won't stop running .

Notices
Questions and Answers If you have general RC questions or answers discuss it here.

My repaired OS engine won't stop running .

Old 03-20-2006, 09:18 AM
  #1  
Hobie
Senior Member
Thread Starter
 
Hobie's Avatar
 
Join Date: May 2005
Location: East Moline, IL
Posts: 129
Likes: 0
Received 0 Likes on 0 Posts
Default My repaired OS engine won't stop running .



Howdy all .
At the end of last flying season I broke the crankcase on my OS .46AX in an inverted dumb thumb crash [:@] . I finally got around to putting a new crankcase on it and fired it up yesterday . It started easy ran good I tuned it back up sounded good but it won't quite running with the carb all the way closed [] .Any ideas on what could cause this ? I am assuming it must still be getting air somehow . Any suggestions on what to look for ? Thanks in advance . I have a Sig 4* .40 ordered from Tower for my birthday and I want to make sure this engine is good before putting it on a new plane . Thanks .

Bruce
Old 03-20-2006, 09:32 AM
  #2  
AllTheGoodNamesAreTaken
My Feedback: (180)
 
AllTheGoodNamesAreTaken's Avatar
 
Join Date: Aug 2002
Location: Somewhere In, NC
Posts: 1,572
Likes: 0
Received 1 Like on 1 Post
Default RE: My repaired OS engine won't stop running .

One method I've used in the past to find air leaks is to use WD-40. With the engine running and the throttle closed, very carefully spray (using the little red hose) a very small amount around the carb base. The WD-40 will be sucked up into the engine and the engine will quit running. WD-40 wont hurt your engine either. If you're real careful, you can pin point the air leak this way. Just don't cut your fingers off with the spinning prop.
Old 03-20-2006, 09:41 AM
  #3  
fokker20planes
Senior Member
 
Join Date: Jul 2004
Location: Ludington, MI
Posts: 197
Likes: 0
Received 0 Likes on 0 Posts
Default RE: My repaired OS engine won't stop running .

Everything Clarence Lee has said in his past articles says that it is getting air from somewhere so you are correct. Try where the carb attaches to case. Is the O-ring still there? Try putting a piece of fuel tubing over the needle valve. I wish I could remember how Clarence said you could submerge the engine in water and by pressuring it you find where air is escaping. If I find an article on this I will post it.
Old 03-20-2006, 09:41 AM
  #4  
TimC
Senior Member
 
TimC's Avatar
 
Join Date: Jan 2003
Location: Lone Pine, CA
Posts: 2,275
Likes: 0
Received 0 Likes on 0 Posts
Default RE: My repaired OS engine won't stop running .

I've used an unlit propane torch also to find an air leak. The engine must be at idle so the added fuel will cause an rpm rise. This was on a gas engine and probably would not have much effect on a glow engine. I posted before the morning coffee had kicked in.
Old 03-20-2006, 09:42 AM
  #5  
bubbagates
My Feedback: (32)
 
bubbagates's Avatar
 
Join Date: May 2004
Location: Elizabethtown, PA
Posts: 8,635
Likes: 0
Received 0 Likes on 0 Posts
Default RE: My repaired OS engine won't stop running .

I also agree, this sounds allot like an air leak. Check around the carb base, the crankcase back plate, the front bearing seal and anywhere else there is a seal that could leak.

If you re-used any seals from the damage then most likely there is your air leak
Old 03-20-2006, 06:25 PM
  #6  
Hobie
Senior Member
Thread Starter
 
Hobie's Avatar
 
Join Date: May 2005
Location: East Moline, IL
Posts: 129
Likes: 0
Received 0 Likes on 0 Posts
Default RE: My repaired OS engine won't stop running .

Thanks guys the carb seal is bad I ordered one from my LHS today . Hopefully that will fix it and that is the only air leak .
Old 03-20-2006, 06:50 PM
  #7  
Tall Paul
Senior Member
 
Join Date: Jun 2002
Location: Palmdale, CA
Posts: 5,211
Likes: 0
Received 1 Like on 1 Post
Default RE: My repaired OS engine won't stop running .

I spread a little goopy around the base of the carb body where it fits on the crankcase, just before I push the carb into the crankcase. This seals that leak area.

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 - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.