Re: Looking for a REAL outboard?
"Direct Charge" could better have been called "Directed Charge" but you know the marketing boys.
<br /><br />But yes, while not as efficiant as a loop charge, the new piston with the big concave deflector dam (eyebrow) proved to be much more efficiant than the older plain vanilla crossflow pistons. More of the intake charge swirled up and stayed in the chamber and more of the exhaust made it out the ports. <br /><br />The downside of this is that the motor needed to be detuned to make up for it a bit. They ran a lot hotter. While the 99ci 1250 had a 34 degree advance, the "direct charge" motors had a 27, then 23, and finally Merc settled on a 21 degree advance to stop from burning up pistons.<br /><br />Perhaps you could run CAM-2 gas and a 30 degree advance for racing, but I doubt it.
I'd shudder to see one at the full 34 degree advance of the 1250, but I bet it would run like hell before it burned up.
<br /><br />In some sick way I have a soft spot for the 1250 just because it's the only "different" 99ci inline and definately the most tolerant of abuse.<br /><br />The '69 1250 was a good outboard poised at the very edge of greatness. The greatness would come soon with the direct charge inlines being the unsdisputed "kings of the lake" through the early and mid 70's. <br /><br />Of course the V6's took over in the late 70's, but IMHO Mercury dropped the ball in the 90-150 hp range with those 3 and 4 cylinder loopers. Call me a dinosaur... but there's nothing like the sound of an angry inline screaming across the lake at 6000.<br /><br />My longtime boating buddy's (Charlie) mother is in her 70's now, but when I put my boat in on little Sebago she often tells me she know I'm in town 5 minutes before I knock on the door to visit her.<br /><br />"I'd know the sound of that damn boat anywhere!"<br /><br />The next day... "you guys were out drinking and screaming around the lake at three in the morning again weren't you??"<br /><br />What's funny is that it's been 3 different boats and three differnt motors. All inlines.<br /><br />-W