Register free!

The Green Industry's Resource Center



Reply
 
Thread Tools   Display Modes
  #1  
Old 04-24-2012, 05:40 PM
jstew33 jstew33 is offline
LawnSite Member
 
Join Date: May 2005
Location: Claremore, OK
Posts: 24
Stihl FS90R 4mix new owner ?

I took the plunge and bought my first Stihl trimmer. Very different beast from the Redmax trimmers I've been using. I have run 5 tanks of quality fuel with Stilhl HP oil and I have a concern regarding the smoothness of engine. 3/4 throttle and the unit runs nice and smooth, but full throttle and the engine housing starts shaking violently and sounds like it's missing. Full throttle in heavy growth it runs fine, but when it's only light trimming duty it starts acting up. I also switched to some .105 line and that seemed like it added enough load to smooth it out some at full throttle. I took it back to the dealer to have them look at it and 2 minutes later they brought it back and said all is fine. I've also noticed that it will stumble for a split second when testing from various throttle positions to WOT. This is the first 4mix tool I've laid my hands on, so really not sure if it's truly and issue or not.
Reply With Quote
  #2  
Old 04-24-2012, 06:27 PM
Richard Martin's Avatar
Richard Martin Richard Martin is offline
LawnSite Fanatic
 
Join Date: Mar 2000
Location: Greenville, NC
Posts: 14,579
It's fine. It's hitting the rev limiter at full throttle.
__________________
Serving Greenville, Winterville and Ayden NC



Reply With Quote
  #3  
Old 04-24-2012, 06:56 PM
MTenterprises MTenterprises is offline
LawnSite Senior Member
 
Join Date: Feb 2012
Location: Brandon, MS
Posts: 327
I have the same trimmer and it does best at full throttle. They are not built to idle or feather much. They load up. Just my experience.
Reply With Quote
  #4  
Old 04-24-2012, 07:00 PM
ScaggyGrass's Avatar
ScaggyGrass ScaggyGrass is offline
LawnSite Member
 
Join Date: Jan 2012
Posts: 54
I have a FS90.. and the dealer says it needs a valve ajustment after first 20 hours..
Reply With Quote
  #5  
Old 04-24-2012, 07:11 PM
Richard Martin's Avatar
Richard Martin Richard Martin is offline
LawnSite Fanatic
 
Join Date: Mar 2000
Location: Greenville, NC
Posts: 14,579
Quote:
Originally Posted by ScaggyGrass View Post
I have a FS90.. and the dealer says it needs a valve ajustment after first 20 hours..
Hmm.. The manual says 130 hours. If he's willing to do the valve adjustment for free then by all means, let him do it. The valve adjustment is simple and easy though. Even a cave man can do it.
__________________
Serving Greenville, Winterville and Ayden NC



Reply With Quote
  #6  
Old 04-24-2012, 07:19 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,367
Quote:
Originally Posted by Richard Martin View Post
It's fine. It's hitting the rev limiter at full throttle.
Richard is 100% correct. Your hitting the rev limiter at full throttle with no load. Mine does the same thing.
Reply With Quote
  #7  
Old 04-24-2012, 07:57 PM
Ridin' Green Ridin' Green is offline
LawnSite Fanatic
 
Join Date: May 2011
Location: Michigan
Posts: 8,889
Quote:
Originally Posted by GMLC View Post
Richard is 100% correct. Your hitting the rev limiter at full throttle with no load. Mine does the same thing.
So does mine, but mine only does it with the edger attachment mounted. It is nice and smooth at WOT with the trimmer head. I guess the trimmer head places a bit more load on it than the edger.

The one and only recommended valve adjustment is needed at 139 hours according to the ops manual, or as needed at any other time outside of that.
Reply With Quote
  #8  
Old 04-24-2012, 08:02 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,367
Quote:
Originally Posted by Ridin' Green View Post
So does mine, but mine only does it with the edger attachment mounted. It is nice and smooth at WOT with the trimmer head. I guess the trimmer head places a bit more load on it than the edger.

The one and only recommended valve adjustment is needed at 139 hours according to the ops manual, or as needed at any other time outside of that.
Strange, mine does it with the trimmer head. Ridin' do you have your guard off?
Reply With Quote
  #9  
Old 04-24-2012, 08:28 PM
Ridin' Green Ridin' Green is offline
LawnSite Fanatic
 
Join Date: May 2011
Location: Michigan
Posts: 8,889
Quote:
Originally Posted by GMLC View Post
Strange, mine does it with the trimmer head. Ridin' do you have your guard off?
No, I'm one of those guys who leaves all that stuff in place.
Reply With Quote
  #10  
Old 04-24-2012, 08:37 PM
GMLC's Avatar
GMLC GMLC is offline
LawnSite Platinum Member
 
Join Date: Jun 2010
Location: New Hampshire
Posts: 4,367
Quote:
Originally Posted by Ridin' Green View Post
No, I'm one of those guys who leaves all that stuff in place.
Me too. What size string?
Reply With Quote
Reply

Tags
4mix , fs90r , stihl

Thread Tools
Display Modes

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

Forum Jump





Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ©1998 - 2012, LawnSite.comô - Moose River Media
All times are GMT -4. The time now is 06:08 AM.

Page generated in 0.07109 seconds with 9 queries