Mercruiser Compression & Alpha 1 G 3

[Dirty Worm]

I am purchasing a 1993 used boat with a Mercruiser 5.7L V-8.(230 hp)<br />I know with O/B the compression should be optimally over 100 psi and the cylinders should be as close to equal as possible.<br />What type of compression should I expect from a I/O Mercruiser?<br />Also, Whats the difference between a Alpha 1 Gen 1,2 and 3. The boat I'm purchasing is a 26 ft with a Gen. 3.<br />Thks

 

[rabidfish]

Re: Mercruiser Compression & Alpha 1 G 3

For compression, the same hold true. All within 10%, I'd hope the compression to be 125-140 plus or minus...<br /><br />For the drive, it will either have an ("Alpha one,Gen 2") Or a ("Bravo" 1,2, or 3 ) <br /><br />The "Alpha" drive is the smaller HP(3.0L to 350MAG) drive, with the dog style shift and the sea water pump in the drive unit. <br /><br />The "Bravo" is slated for the larger HP (4.3L to 8.2L)engines. It has a "cone" style clutch and the Seawater pump mounted on the engine, inside the boat. All the bravo drive use basically the same upper "driveshaft housing" unit. The difference is in the lower half, or "gearhousing"<br /><br />The Bravo 1 is the standard drive, that swings up to 16inch diameter prop. <br />The Bravo 2 is the large boat drive, swings the 20inch diameter prop. <br />The Bravo 3 has the counter-rotating twin props.