North Australian FISH FINDER TM forums

Just upgraded the outboard on my mud boat 485 trail craft from a 90hp ETEC to a 2015 115 hp Yamaha.

Can't wait to water test her tomorrow.....Should go like a rocket.

The ETEC WOT was only 51 km so I hoping for better top end speed and better cruising.

My money on about 70km what you reckon?

Nice. Given that you have been on the forum a long while and have no vested interests (that I know of ), it will be interesting to hear your thoughts on both motors once you have had the new one on the water for a while.

Very nice

Hey tran.
My 115 yam is pushing a lot more boat than yours. But I recently put on a 4 blade prop. I was a bit sceptical, but George reckoned it was worth a try, so I tested it out. I was getting a top speed of about 55. Sitting on 50 kmph was about 5500 rpm, not has a top speed of about 63 kmph, at 50 kmph it now sits on 4700 rpm. It won't rev out past about 5500 rpm, but I'm getting a higher top speed so not real fussed. Haven't don't a good run to Test economy properly, but will be a lot more economic now. You are more then welcome to grab it and test if it's worth while getting one. Might get a bit scary what the top speed would be tho, my hull would probably weigh twice yours.

Im interested to see what speed you get. I just recently swapped my 80hp yammie for a 115hp yammie on a 490 top ender but im still putting my boat back together. Let us know how she goes.

Yeah got compare apples with apples though

How many revs did the ETEC pull at WOT.

You got a few extra horses and a little more weight on the transom ???

But if you get the height and propping right i'm sure you will be more than happy with the Yammy

mickkk wrote:Hey tran.
My 115 yam is pushing a lot more boat than yours. But I recently put on a 4 blade prop. I was a bit sceptical, but George reckoned it was worth a try, so I tested it out. I was getting a top speed of about 55. Sitting on 50 kmph was about 5500 rpm, not has a top speed of about 63 kmph, at 50 kmph it now sits on 4700 rpm. It won't rev out past about 5500 rpm, but I'm getting a higher top speed so not real fussed. Haven't don't a good run to Test economy properly, but will be a lot more economic now. You are more then welcome to grab it and test if it's worth while getting one. Might get a bit scary what the top speed would be tho, my hull would probably weigh twice yours.

Hi mickkk, what hull have you got?

I've got the 115 on a 5 metre Seajay bowrider and can get the revs up to about 6000 for about 60 km/hr on smooth water. Given you get the higher speed with lower revs (this may be a stupid question) but do you find you're getting a lot more kms per litre?

Top speed doesn't concern me too much, I'm all about getting more kms!

Took her for run from Lizzy to 6 mile ground today and all I can say is WOW .

The torque was great but not as good as the 2 stroke Etec . Theses were the numbers with 17 ss pitch prop.

4000 46km
4500 53 km
5000 57 km
6000 66 km
6200 68 km

It easily revved to 6200 an I didn't get to trim it out as I was worried about hitting red line on the first run. Ahaha. The motor just come with the rev gauge so still need to buy the nmea 2000 to connect up to my HDs 10 to tell fuel usage.

Happy with the cruising speed....

Diffenitely worth going to a 19 pitch but this is my mud boat so not sure I'm going to spend more money on it. Maybe get a 19 Ali prop as it get used more down the creeks then in open water.



I never had a problem with my Etec . It was just loud and a pain in ass to get adding oil . Diffenitely always prefer 4 strokes over 2.

The Etec WOT was 51 km at 5300 revs.

Unfair to compare a 90 vs 115 regardless of the brand.

you gotta be happy with that economy should be good too

make sure your boat is fully fuel and loaded next test the decide on prop's


just as a note too never got your ETEC to full potential on revs either.
but who cares...................

your miles ahead now

fff1964 wrote:you gotta be happy with that economy should be good too

make sure your boat is fully fuel and loaded next test the decide on prop's


just as a note too never got your ETEC to full potential on revs either.
but who cares...................

your miles ahead now

Thanks had full 120 l tank today but will do more test in next couple weeks with couple bloke and esky full or beer.

Every thing I read on the etec 90 said 5300 was recommended max rev. Territory Marine and a marine place in Adelaide where the boat originated from said it set up at the optimum prop and max rev.

What does your etec rev to?

Evinrude like to SAY 5000- 5300 minimum 5200- 5500.

from research i did.

but that all good that what i ran mine at when i had it.

i think the new V4 are different again.

CHEERS