Can I convert 1973 7.5 to a 9.8?

huntin dawg

Petty Officer 2nd Class
Joined
Nov 12, 2009
Messages
197
According to my shop manual the only difference between a 1973 7.5 HP and 9.8 HP is the type of carb they have. Breaking that down further the difference I see is the main jet size. It's .035 for the 7.5 and .047 for the 9.8.

Can I convert it to a 9.8 simply by changing the jet to a .047?

Thanks,
HD
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
Re: Can I convert 1973 7.5 to a 9.8?

Nope ..You need the KB11A carb body as venturi and pullover is different.
 

Downwindtracker2

Petty Officer 2nd Class
Joined
Jun 25, 2008
Messages
110
Re: Can I convert 1973 7.5 to a 9.8?

I don't know what a pullover is,either,but I have read the porting is different.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Can I convert 1973 7.5 to a 9.8?

You need more than the carb to convert them - the cylinder blocks are different. The 7.5 block is marked "COMET" on it, which denotes smaller porting. They use the same block casting but they're machined differently. Not sure if it holds for all 7.5/9.8s for all years, but the ones I've seen have definitely had smaller ports on the 7.5...
 

huntin dawg

Petty Officer 2nd Class
Joined
Nov 12, 2009
Messages
197
Re: Can I convert 1973 7.5 to a 9.8?

Now that makes sense.

I'd still like to know what pullover is.

HD
 
Top