99 175 efi ecu swap 200hp

[cshoemate]

Hello all! I have a deep v lowe gls 19ft with a 99 175 efi. I've been looking to increase top end so I bought a 200hp ecu and installed. Absolutely no change in performance lol same rpm @5500. Any explanation for this?

[cshoemate]

Forgot to mention prop is enertia 13.8x20

[OnPad]

Maybe your going about it backward. Could be a 150 ecu, with a leaner fuel curve would be faster? Or more likely, the hp sticker on the side of the ecu doesn't make as much difference, as does port configurations.

[cshoemate]

Maybe your going about it backward. Could be a 150 ecu, with a leaner fuel curve would be faster? Or more likely, the hp sticker on the side of the ecu doesn't make as much difference, as does port configurations.

Oh I see, I was going by what the mechanic said but that makes sense. What are my option to increase top speed?

[OnPad]

Boat setup is your easy bet. Things such as, engine height, setback, weight distribution, prop choice, etc.

This particular mercury engine, ratings are achieved by different port configurations in the same displacement block. Without changing your porting it would be difficult to find more than a couple hp with bolt ons.

Welcome to the site!

[25two.stroke]

You are hitting a wall with HP and TQ numbers that the engine can physically produce as its set up. Sure you got a higher rev-limit now in your ecu, but if the engine isn't making enough power to spin your 20p enertia more than 5500 then you won't see any difference. Like he said above, boat setup is more critical: prop, setback, weighting etc.

[cshoemate]

You are hitting a wall with HP and TQ numbers that the engine can physically produce as its set up. Sure you got a higher rev-limit now in your ecu, but if the engine isn't making enough power to spin your 20p enertia more than 5500 then you won't see any difference. Like he said above, boat setup is more critical: prop, setback, weighting etc.

Do you think I would be in a safe RPM range if I went to a 14 by 19 prop?

[25two.stroke]

"Safe" is dependent on how well the internals of the engine were assembled and your confidence in the fuel delivery system. 7000 is a safe rpm limit for a 2.0/2.5L engine...so a 19 or 17p prop wouldn't even get you near that.

[OnPad]

What he said.
I would recommend deleting oil injection.

You might also achieve the same or better results by raising engine height?

[tlwjkw]

bobby V. has ran probably ever combination of production (2.5's) ecu to horsepower that could be done.. 150's, 175's on 200's, 200's on 150's, vice versa etc... 824003 1 up ta tha A27... 99% of 'em either ran tha same on any horsepower if tha ecu was good or didn't run at all depending on tha "health" of tha motor and/or ecu.. Merc's QC department was "on point" as usual ... only ones that were different were tha PM ecu's and that was jus tha limiter.. ya'll should ask him 'bout it some day....................

go here ta geta "start" on set up.............. be sure ta get a water pressure gauge.

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