Outboard EFI

[SurfnFish]

Not realizing the impact of altitude and cat hull drag, when I bought a new 9.9 Tohatsu for my skiff I thought it would suffice to cruise at the 10 mph speed limit on my fave lakes. Reality was regardless of prop changes and jack plate to minimize lower unit drag I could never get the RPM up above 4700 which kept the speed around 7 mph.
So went with the ECU being reflashed at Outboardf EFI, which according to them would pump the hp to 20, as Tohatsu 9.9/15/20 hp units are the same unit other than ECU programming and air intake restrictors.
So in went the reflashed ECU and out came the air restrictor and what a difference it made...on the lake by myself, opened it up and 20 mph+ at 6000 rpm was on tap. Outboard EFI reflashes a lot of different motors, so if you're needing more power/speed...

store/product - Outboard Efi

www.outboardefi.com

 

[Evan B]

Not realizing the impact of altitude and cat hull drag, when I bought a new 9.9 Tohatsu for my skiff I thought it would suffice to cruise at the 10 mph speed limit on my fave lakes. Reality was regardless of prop changes and jack plate to minimize lower unit drag I could never get the RPM up above 4700 which kept the speed around 7 mph.
So went with the ECU being reflashed at Outboardf EFI, which according to them would pump the hp to 20, as Tohatsu 9.9/15/20 hp units are the same unit other than ECU programming and air intake restrictors.
So in went the reflashed ECU and out came the air restrictor and what a difference it made...on the lake by myself, opened it up and 20 mph+ at 6000 rpm was on tap. Outboard EFI reflashes a lot of different motors, so if you're needing more power/speed...

store/product - Outboard Efi

www.outboardefi.com

Curious what props you tried? Seems like a low enough pitch would've gotten the RPMs up.

But this is much more fun.

 

[SurfnFish]

Curious what props you tried? Seems like a low enough pitch would've gotten the RPMs up.

But this is much more fun.

tried a couple from The Prop Shop in WA (good crew who refund returned props if not damaged) ) and the highest RPM was reached with the 'least resistance' prop available for 14 spline, a 9.25 x 7. With the stock 10 x 7 four blade thrust prop could not get the rpm above 3800.
Talked to Tohatsu about it, who gave me the helpful advice 'altitude kills hp, should have gone with more hp'.
Now running a 9.25 x 8, and if anyone needs a 14 spline prop, have a selection...