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merc inline 6 info

R

revlimiter776

Member
i have recently acquired a 90 horsepower inline 6 merc for my 74 trv 16, i am happy to have an era correct motor for this boat, as far as i can tell, the boat was originally rigged with this motor. being an evinrude fan i have had nothing but blue and white on this boat since i got it, worked 140's 115's even 3 cylinder 70's, i would like to know what can be done to tweak this inline six, i have seen some elaborate setups, but may not be looking to go that crazy, any mercy tips would be greatly appreciated thanx
 
Are you looking to actually try to wring more out of that in-line 90 hp? Because if you are just stop right there and leave it alone. I don't really remember anyone modifying the 90 hp when it was a new production engine.That motor was at the bottom end of the horse-power scale and is in fact basically a de-tuned 115 hp with smaller carbs and different timing. The Merc in-lines were all basically the same design and used the same components for years. The powerhead " guts" and carburetion plus port work and ignition timing is where things were tweaked.

You would be better off trying to find a used 115 if that's what you really want as far as more horsepower It also depends what year engine you want too. I mention the 115 as that was built for the most recent years in an in-line 6 version. But there are plenty of 125, 135, 140. and 150's out there too! Just be sure to find one that isn't too tired.

If you want the 90 as your engine ( it is a good motor) then focus on set-up. Prop, engine height, WOT rpm, set-back, A jack-plate, these will all contribute to what you will be able to get out of your " tower of power".
 
Go to the inline newsgroup and ask them.

Using Outlook or Outlook Express:
Go to Tools, then Accounts, then News, then Add News, set up your name and email.

Server: news.kraits.org
Newsgroup: bigweek.mercury-inlines

I know it's complicated to get there, but once you set it up the first time, you can just open Outlook and get it immediately.

There are a lot people there who really know their inlines. Depending on the year of your motor, there may be some things you can do. I know that certain years of 115's can be turned into 135's fairly easily. Not sure about 90's, but there may be something you can do.
 
90 HP INLINE

IT DEPENDS ON HOW YOU ARE GOING TO USE YOUR BOAT . THE 90 I-6 HAS A LOT OF BOTTOM END , THEY HAVE SMALL CARBS,LOW PORTS . IF TOP END IS YOUR MAIN CONCERN , YOU MIGHT WANT TO LOOK FOR A 150 POWERHEAD . YOU SHOULD BE ABLE TO FIND ONE CHEAPER THAN MODIFYING THE 90 . THEY HAVE BIGGER CARBS, PORTED PISTONS , AND MAKE A LOT OF POWER ON TOP END ( 6000 RPM ) . IF SKIING IS YOUR MAIN DEAL , THE 90 WILL WORK WELL FOR YOU .
 
inline six questions

well, i appreciate your input guy's, i will try to set up my outlook express to get over to those inline six guys, i do have the motor set back six inches and the center of the propshaft three inches below the hull and am running a 21" hustler aluminum prop, 5500 rpm 51 mph, i had an old black max i sold, i'm kinda wihin it was here, i have priced new motors and they are crazy expensive, anybody selling a 90's 135?
 
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