Converting merc/mariner to XS model spec

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Hi
Question for the merc 4 stroke boffins. I’m not up on the new engines at all...

i have a 2016 115hp 2.1l CT engine. A great thing and really impressed by everything about it. But I’m now aware that there is an XS 115 version of this model too. This engine is somehow mapped from factory to allow an extra 200 rpm at the top end and produces a little more power.
So clearly the engine I have is capable of this having everything but the limiter or map the same.
Is there a way to allow mine to rev to 6200 rpm ? I could really do with it. It is literally almost perfectly propped with a 19” tempest plus...but 100% perfection would be if it was allowed to rev a tiny bit more. It can touch the limiter on occasion at 6150 rpm and 43mph. To have another 50-100 rpm would be amazing. Thinking this as an alternative to another costly prop change. In my case I think going to a 21” isn’t the best alternative unless I can find a 21” tempest or mirage. An expensive gamble given how rare and expensive they are where I live.
Thanks.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,633
Usually the best, sure-fire way to get the wee bit more power is to buy it in the First Place, or do a trade-in later. Just repropping for a higher rpm isn't going to raise the HP. It may be just mapping, or it may also include some differences in Cam Timing, Valve lift, better flowing heads/intake/exhaust. I guess you could speak real nice to a Partsperson at the Dealer and see if he will let you look through the Parts Books to compare a lot of parts
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
50,227
best way to convert any outboard is a 3 step conversion process
  1. sell what you have for a small pile of cash....this converts your asset to cash
  2. empty the contents of wallet and bank account to pile making pile slightly larger.... this converts the pile to a more useful pile
  3. buy what you need turning the larger pile of cash into a new outboard...
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,930
Try some of the guy on west coast to see if they have the map...ECU and decals only difference
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,348
Thanks guys.

Agree with whats been said usually...but the XS and the CT I have are identical in every component and all else...apart from the rpm limiter.
Currently I’m literally a minuscule amount off being perfect.
Just wondered if it was a full ecu job or a simple restriction that can easily be removed.
Suggestions above don’t mostly make sense to me financially.
It would be madness for me to sell my almost perfect new engine (not fitted by me) for thousands less than what it was bought for...only to buy a new engine for thousands more...for an extra 100 rpm.
Just really asking if it was an easy adjustment and if anyone had done it. It’s not as if I’m asking the usual conversion from x hp to x+ hp that share the same block but need different carbs, manifolds, heads etc etc. They are both identical and identical apparent HP rating but just a slight variation in rpm.
Cheers guys.
 
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