9.9hp upgrade

[Newo]

Hi, I was wondering if it's possible to upgrade my 9.9hp four stroke engine to a bigfoot is this possible? And if it is, what do I need to change?
I use this auxiliary engine on a 20 foot boat mainly for trolling, maximum speed wot is 4 knots, I would like to upgrade hoping that I would be able to increase my top end speed to at least 6 knots. Any ideas if this is possible?
Thanks in advance

 

[galamb]

Good question.

I don't fiddle with 4 strokes very much at all. Looking at my earlier service manuals there was at least a time when the block size was different between the 9.9 and the 9.9 big foot (the 9.9 and 8 had the same block, the 15 and 9.9 Big Foots had the same block).

The other major difference with most Big Foot models is the gears in them. They have a somewhat lower gear ratio - so easier to turn a larger prop to give more thrust, but not top end speed - so meant for pushing weight at a slower speed, all else considered.

Your best bet is "ask the experts" - drop a note to Merc's tech support - here's the link - just fill it out and zip it off. They are usually pretty good about getting back to you within 24-48 hours.

http://www.mercurymarine.com/contact-us-online/