first mercruiser - what should I look for?

[vroom ZOOM]

got this mercruiser 2.5, found a drive for it, but the U joint on the top is a bit rusty. before I buy the drive, is the rust on the u joint a serious problem or not? the drive apparently worked well until something happened to the engine. the prop is on it and doesn't seem to have any damage.so should I go for it? also, are there any other things I should watch out for on the 2.5 mercruiser? thanks.
P.S. looked at the bellows, they seem to be ok, and the metal engine parts (or maybe its the gimbal bearing) down in the bellows have one very small slight surface rust discoloration. is that a sign that the bellows are leaking?. I would think that if they where leaking the whole part would be covered in rust.

 

[alldodge]

A little surface rust is not an issue, but if the U joints are binding and do not move smoothly, they would need replaced. Pull the drain plug on the drive to see if you find metal or water.

Do you know what ratio the drive is? If its to high your 2.5 may not be able to find a small enough prop

 

[vroom ZOOM]

its a 1.98

 

[alldodge]

I'm finding 1.94 for a 2.5 but that should not be an issue for you

 

[vroom ZOOM]

ok, im ready to install the drive, should I buy a new gasket or can i use RTV?

 

[alldodge]

I would always use a new gasket, the last thing you want is a slight leak and it ruin something, cheap insurance

 

[vroom ZOOM]

ok, also what fluid do I use in the trim pump?

 

[alldodge]

ok, also what fluid do I use in the trim pump?

10w30 motor oil