Hello, I just bought my first sea...

[Rosehill1]

Hello,

 I just bought my first sea ray 270 Sundancer. 1986 with dual mercruiser 260 hp I/O drives. I’m looking for information on the engines as the starboard overheated last week while running at about 3200 rpm, oil pressure seemed low to me as well at 22-25 psi. Port ran fine by the gauges. Maybe a six mile round trip with lots of no wake zones.  Any feedback is greatly appreciated.

Rosehill1

[Steele_y_Tutz]

Two ways to get what your wanting. First is to call Mercruiser and see if they can get you the books. Or get yourself the repair manual. The repair manual is your better bet as it's more detailed.

[wingless]

Welcome to the forum.

Good luck w/ your new boat.

+1 on getting the correct FSM for the engines. It is a guessing game w/o that documentation. The online parts search w/ engine S/N will show the correct P/N for that manual(s).

Each 454 MAG MPI Horizon engine on my 2000 380DA has about a dozen systems dedicated to heat removal. All must be operating properly.

The instrumentation is also important to be providing correct readings.

My preference for oil pressure validation is to use a 1/8" tee, nipple and a mechanical gauge. It is quick / easy way to check if the gauge is right or wrong.

[Rosehill1]

I’m sorry I don’t know what FSM stands for, please I’m new to the boating community.

[wingless]

My fault, sorry.

FSM - Factory Service Manual

In this case it is a 1" thick Mercruiser 8½"x11" paper manual created specifically for the engines on your boat. It usually covers a range of model years and covers several similar engines, with additional detail provided showing the differences between those engines.

WRT (With Respect To) the original inquiry, there are any number of reasons for the overheating. If real overheating (not just messed up instrumentation) common faults are raw water path corrosion, failed raw water impeller, or obstructed raw water path.

[Steele_y_Tutz]

I have this one around here somewhere. It's very detailed and is a must for every boat or vehicle you own.

https://www.themotorbookstore.com/mercruiser-stern-drive-repair-manual-plus-tr-trs.html?cmp=googleproducts&kw=mercruiser-stern-drive-repair-manual-plus-tr-trs&gclid=Cj0KCQjwssyJBhDXARIsAK98ITTnguipg2qtbzu5jFwdamoZviNWJ9bv1oXUbbBVF9HpHwhZWHf2Pm8aAvfFEALw_wcB