Small Engines (Lawn Mowers, etc.): Clutch on scott bonner 17inch reel mower, scott bonnar, scott bonner

Question
Hi Eric, this question is coming from Perth, Western Australia.

I have a 30 year old, 17 inch scott bonner reel mower ( only recently inherited) with a 3 hp B & S motor. The engine runs fine when started and the clutch engages normally to start with. However after a couple of minutes at idle with no clutch engaged, the motor starts to labour and suddenly the clutch while still not manually engaged clicks in and the blades start to turn. They cannot be stopped even with the clutch lever.

I have noticed the cluch assembley on the side away from the engine gets very hot around the drive shaft. Is there a bearing in there that could be overheating and causing the problem?

Looking forward to your assistance. Barry

Answer
There may be a primary clutch thrust pad.  Is you mower a Scott Bonnar Model 45 or 3.5hp 17” Reel Model No. 45058

Scott Bonnar Primary Clutch Thrust Pad
Fits: Replaces OEM: A333112
http://mail.rgs.com.au/pictures/FilesAsMenuItems/info/new_parts.pdf

The link below covers a similar issue another ower had with the clutch.  Take a look at the link and let me know if it helps.

http://www.outdoorking.com/forum/ubbthreads.php?ubb=showflat&Number=18392

Eric