twin 250 cavitation problem
 

I have a 1998 29' fountain sportfish with twin mercury efi 250's. I just purchased the boat last year and have been having a hard time with the props cavitating, especially the starboard. This only happens in rougher water and tonight I couldnt even get on plane in 1-3 foot waves. I usually start with the tabs up and the engines trimmed almost all of the way down. What am I doing wrong?
Thanks Jason
P.s. new to this site

Do your props have the ventilation holes in them? Three or four holes about 3/4 of the way drilled through the hub? And are you using a 3 or 4 blade prop?

I would also check the mounting height of motors, they may be too high

Post this on The Hull Truth website, much more experience over there with the outboards.

No ventilation holes and they are 3 bladed stainless steel props. I dont know how much lower they can go.

I know on my outboard cat I used to let them cavitate to 5k before they would start to bite, and get me on plane.. motors were real high, and surface cleavers

Its so frustrating. My wife doesnt want to go on the boat with me because I get so upset. Yesterday I was able to get the boat on plane and going fine but when I would hit a decent wave the starboard engine would cavitate. Where should I start my trim tabs at?

Drop the motors one hole if possible, cheapest way. Also look into some props.

Why is everyone suggesting that he drop the motors without knowing the type of boat, length of the lowers or anything else. Before you even think about dropping the motors I would see where the ant-cavitation plates are when you are on plane!!! To do that take a photo of where the lowers meet the water when up and running. I think you need to cross off the easy stuff - is the hub in the prop messed up (I know that once they go they usually are done but you never know and it is a 15 minute check), is the prop true and the same size as the other prop, is the shaft bent, is there something on the bottom of the boat that is causing the prop to get air or unclean water (are there barnacles, is there anything installed in front of this prop like a transducer that is not installed in front of the other). Where are you located and what size props are you running??

This is a 1998 sportfish - look at the photo and see if your engines are set at about the same height. http://boatsalemarket.com/wp-content...console--6.jpg

Motors look deep to me.. Try different props...