converting merc 9.8 to a 15 ??

[siudog]

I have a 1979 Merc 9.8. I don't have the s/n as I'm typing, but I know from the dealer that it is a '79. I've been told by many that the 9.8 engine was the basis for the 15 and 18 HP versions and that the only difference was the carb. Unfortunately, nobody knows what carb will make it a 15, or rather the dealer won't look it up. I'm surprised that piston size, porting, or compression are supposedly the same and that the carb is the diff. Any ideas on this?? What carb do I need and does anyone have one f/s? Thanks!

 

[WillyBWright]

Re: converting merc 9.8 to a 15 ??

Welcome to iboats and you got some really bad information. There was the 6, 7.5, 9.8 all based on the same block. The next size in that generation was the 20. Never anything more than 9.8 out of your block. The newer generation 9.9s and 15s are based on the same block and the carb is only one of many differences. The next size up is the 18, 20, and 25Hp series.

 

[Yellowlabs66]

Re: converting merc 9.8 to a 15 ??

Great info Willy.. I have a 9.9E so where would I find the infromation for converting up to 15?

 

[Laddies]

Re: converting merc 9.8 to a 15 ??

it's not the same block as the 15 either, the 9.9 is 12.8 cu in and the 15 is 16 cu in