Just an FYI for people, because I see questions posted but ussually no answers, or people don't know. I have a 2003 75hp four stroke and wanted to upgrade to a 90. I reviewed all the parts in the engine and the only thing I found different were the carburators.
I bought 90hp four stroke carbs on ebay late last fall, and never did anything with them. Last night I installed them and it idled perfect. Tonight I took it to the lake and it ran much stronger.
It was up from around 5200-5300rpm now to 6000-6200rpm, ran 6mph faster. It should run even faster, because now I need to buy a higher pitch prop due to the over rev.
I would say that this is a strong 90hp motor now. I know Yamaha rates it at 100 so I assume its somewhere in between.
Now to decide what to buy for a prop. It is currently a 17" pitch. Maybe a 19" or 21". I believe the max rpm range is between 5300-6000rpm.
I bought 90hp four stroke carbs on ebay late last fall, and never did anything with them. Last night I installed them and it idled perfect. Tonight I took it to the lake and it ran much stronger.
It was up from around 5200-5300rpm now to 6000-6200rpm, ran 6mph faster. It should run even faster, because now I need to buy a higher pitch prop due to the over rev.
I would say that this is a strong 90hp motor now. I know Yamaha rates it at 100 so I assume its somewhere in between.
Now to decide what to buy for a prop. It is currently a 17" pitch. Maybe a 19" or 21". I believe the max rpm range is between 5300-6000rpm.