91 force 9.9

[bikebunky]

hey guys
How do you turn a 9.9 into a 15. someone told me a carb jet change. Have seen the postings on the coil problems and the lack of parts. bought a yamaha 8 because I couldn't find a coil for my 9.9. found one on ebay 5 years later and got the eng running. a few problems with the water impeller and idle but I'll figure it out.

 

[Frank Acampora]

Re: 91 force 9.9

You don't! While the block is the same, you need to change exhaust and bypass port timing (duration) in addition to a carb change. This requires complete disassembly of the engine and special measuring equipment to determing how much to grind off the cylinder walls at the port tops.