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2019 9.9 conversion to 20

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BlackKnight755

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I am in the market to purchase a new outboard engine for a 14 foot aluminum boat that will be used for powering my boat in small rivers in my area. I have a river system in my area that I enjoy fishing in that restricts engines to 9.9 horsepower. I will also be using the engine in other rivers that do not restrict engine size. I want to purchase the Tohatsu
MFS20EEPTS 20 horsepower engine. I would however not be able to use it in the restricted river.

I have been told that I can purchase a MFS9.9EEPTS 9.9 horsepower engine which is the same engine as the 20 horsepower and change the ECU and it will turn the 9.9 into a 20 horsepower engine. Is this true? I remember many years ago when there were 9.9 and 15 horsepower engines that were almost the same but were regulated by fuel delivery and timing mostly but I have no idea about these new motors. If this would be possible, is there anything else that would have to be changed?

Any help would be greatly appreciated, BK​
 
Swap out the ECU:
3RS064010MECU ASSY (20)$900.00


And remove the 9.9 restrictor:
3RU035360MRESTRICTOR (MFS9.9)

There are 3 different ECU modules (9.9, 15, and 20), and two restrictors (9.9 and 15 -- the 20 runs without one). You must run the appropriate restrictor with its matching ECU, or the airflow will be wrong, and the mixture will be off.

If you want an ECU, send me a PM.
 
If it was me I'd just replace the 20hp decal with the 9.9hp decal and call it a day. Just keep your speed down on that restricted river. Darn liberals, they take the fun out of everything.
 
Yeah, except the stickers are not available:
3RU878011MDECAL SET (MFS9.9E) BLUE WING LOGO (2018)$42.27NotesOut of Stock

However, the older decals are available:
3RU878010MDECAL SET (MFS9.9E) 2017 ONLY$42.27

 
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