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-   -   K&B 3.5 (http://www.rcuniverse.com/forum/rc-boats-general-discussion-77/11114898-k-b-3-5-a.html)

Ram Jet 06-11-2012 03:57 PM

K&B 3.5
I just rebuilt a K&B 3.5 outboard. Is the prop drive dog supposed to slip on the output shaft or do I need a new drive shaft/output shaft? I have the K&B lock nut and the "shock tubing" installed. I'm not new to engines but I am new to the K&B 3.5 outboard.


Ron Olson 06-11-2012 08:22 PM

RE: K&B 3.5
I'm trying to remember as it's been a while since I worked on one. It seems like one model used a set screw and another was a press fit. If it's sloppy then it needs a thrust washer. I've used the ones from Octura and Aeromarine as they're easier to get than anything from K&B/MECOA.
Their schematic isn't any help but in a line drawing it shows a set screw but not in the exploded view, http://www.mecoa.com/kb/89/8907-exp.pdf .

frank haydu 06-17-2012 07:29 PM

RE: K&B 3.5
yes they are meant to slip on and off to replace the trust washer which goes between output shaft housing and the dog drive , the dog drive should have 2 allen set screws to tighten against the output shaft , i recommend a little loctite on each for vibration purposes. the thing you want to watch for is wear in the housing keep it well lubed with water proof grease and a well balanced prop or you are going to go through alot of output shafts , i found out the hard way , i have a k&b 7.5 outboard motor on a prather lap cat 2. well best of luck hope that was helpfull

Dan S 06-18-2012 11:06 AM

RE: K&B 3.5
This link should also help you: http://www.mecoa.com/kb/89/8907-exp.pdf


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