15.5 OHV Briggs knocking at idle

Reply

  #1  
Old 12-02-06, 06:57 PM
e40
e40 is offline
Member
Thread Starter
Join Date: Oct 2005
Posts: 12
15.5 OHV Briggs knocking at idle

My very lightly used Craftsman mower with the 15.5 Briggs motor seems to be knocking at idle. It sounds like it's coming from the back side (bottom end) of the block. Once I increase the RPM, or apply a load such as the snowblower attachment, the knock goes away. Any ideas? TIA
 
Sponsored Links
  #2  
Old 12-02-06, 07:35 PM
v8driver's Avatar
Member
Join Date: Sep 2005
Posts: 767
are the mounting bolts (what holds the engine onto the frame) tight? and I mean very tight....
 
  #3  
Old 12-02-06, 07:43 PM
e40
e40 is offline
Member
Thread Starter
Join Date: Oct 2005
Posts: 12
They seem to be. I don't see any physical movement either.

I was just on the Briggs site and they said to check the flywheel, and pull the head and clean out the carbon. So I'll give that a shot and see what happens. (fingers crossed!)
 
  #4  
Old 12-02-06, 08:09 PM
michaeljp86's Avatar
Member
Join Date: May 2005
Location: USA
Posts: 478
I have a 3.8hp techumse verticle shaft engine that did the same. It was my grandmas mower and it got so bad Ididnt want to use it but she said mow my yard. Anyways it got worse and finaly had no compression. I took it apart and the oil pump is plastic and cracked. I super glued it together and its been running for about 4 years now. It still knocks for a few seconds when I fire it up in the spring but runs like a top.
 
  #5  
Old 12-02-06, 08:42 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 16,818
Check the engine mounting bolts and the PTO pulley bolt to be sure all are very tight.
 
  #6  
Old 12-03-06, 09:21 PM
v8driver's Avatar
Member
Join Date: Sep 2005
Posts: 767
You won't really see the engine move much when running, or be able to move the engine much by hand back and fourth when not...
They must be very tight... or it will cause a knock noise at idle and usually clear up at speed (the bolts are bumping around in the frame mounting hole)
 
Reply

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes