94 Yammy 115 V4 to 06 175 Opti

[ozscott]

I have been thinking about an upgrade mainly because I would like to get offshore more and I only have 150l of fuel - the opti run at 4000rpm is going to chew less fuel than the Yammy.

The 06 Opti has more power than I need but is well and truly within the transom rating - the transom would have to be built up height wise. It has done 800 hours and was sold and serviced by a mate who says its a good motor and I can get it at a reasonable price I think.

Has anyone got any experience with the 175 block and in particular the 06 year engines who can add to the question of whether I should grab it.

Cheers and thanks

PS. There might be a good second hand Yammy (with a new regulator as of today..) on the market soon. PM me if you are keen. My threads on the motor can be searched on this site.

[cormorant]

Honestly - fuel is pretty cheap compared to building up transoms on some boats. Rating is not really the same once you have messed with the transom. If you didn't already guess I stay away from boats that have had transom jobs done , then reprop , bigger battery, steering , fitting on them so what you gain in possible better resale with a newer motor you lose with a modified boat and possibly a insurance hassle depending on how well it is done and documented. Watch transom weights especially if the transom modification is a jack plate as they add a multiplyer affect with weight further back and can cause broaching in some hullsor bad behaviour. Ten again it can fix a lot of bad behaviour as well so try and find a sistership with similar mods. Ie let someone else be the guinea pg. ..

Honestly motors once that get over 1000hrs are harder to find buyers for hence why people change em out at 800 odd. Fancy 2 strokes are not loved over 1000 hours regardless of colour so I hope it is a very very good price and just outside 5 year warranty and finance?

Can your mate not eventually source a 150 or save a bit and do the perfect motor you really want for the next 5 odd years. Not to piss on your mate but he is probably trying to presell the 2nd hand , trade in one so he can actually offer a decent trade in price and get the repower deal done. Can he source demo motors at end of season at a decent rate to help you out?

Even fancy 2 strokes and 4 strokes when not loaded up at midrange revs use fuel at possibly a higher rate than if they are the best match for the boat but a lot is the propping purely due to the capacity and pistons moving back and forth.

A cruise tank is cheap for the longer trips, your yammi loves higher revs and load and will last another year and not decrease in value more than a few bucks as long as you know it is reliable/ maintained

Yep the extra power would be used ;D so fuel saving may be less than you think but would still be a bit if it wasn't flat and you kept off the go lever- do you have that restraint- I don't - they are just coming onto the fun noise at 3600rpm;D and then pull like a train

[ozscott]

Thanks mate - you make good sense.

Cheers

[Noelm]

not 100% sure the fuel savings on a 175 opti compared to a carby 115 would be enough to sell me on it! compared to 175 carby model, then that would be a different story, HP is HP, it takes fuel to make it. the Opti is a BIG motor.

[cormorant]

I'd also forgoten thet physical cowl size let alone the CC's as I mentioned.. Bloody monsters and if you have bait boards and stuff that need changing that is all extra $. On older hulls it is a pain with small areas to tilt motors into and cripples cables in tight runs

Truth is when you have the HP you put the hammer down. You don't get out of the habit if conditions allow and it can make a huge difference in time if you have along run wide and can actually run at the higher speed without back injury. Just only so many days most hlls run that speed in comfort. You do get comfortable with higher speeds very quickly in a good hull as they all perform better when they have enough to get up and boogie.

Classic me commenting on this thread as in years gone buy I have had stupid stupid HP and run silly speeds in the good hulls and come home on a few days a cripple but with a smile on. Wish I still had the stupidity health and money to do it!!!!

[timddo]

Opti 175 should chew much less fuel at 4000rmp then a 115Hp. Fuel is like $1.47 a litre now, we should expect it to go up to $2 a litre. If the opti chews say 16 litres/PH cruise of 25 knots, i would be happy.

The OPTI 135-175 is a bloody huge motor though

[bigjimg]

Maybe I'm just used to looking at my 135,they're not that big,certainly wouldn't call them huge.800hrs done since 06 is bugger all.I'm sure it will last quite a few more years and serve you well.It'll push your boat without even trying,prop it right and the fuel savings will be in your pocket.Jim

[Greg P]

It will drink more than 16l/hr at that 4000 rpm level and hull weight - no doubt. I dont think your savings would be as much as you think.

[mustang5]

I dunno mate, I still think to this day the best most reliable motor I have had was the 115 Yammy. If it pushes your boat well I would stick with it. You can light em on fire, sink them, not flush them for months and even run them without oil and they will still keep kicking along. From experience embarrassingly :)

There are plusses to extra h.p of course, but you always run the risk of having it a$$ heavy which make them a pig in rougher water..

[ozscott]

Thanks gents - very much appreciated as normal. I will keep her.

Cheers

[Noelm]

don't let us scare you off a newer motor, but as with all big investments, you need to have your eyes and ears open to all sides, you will save fuel, how much compared to your 115 is anyones guess, I would think if your boat is "happy" with the 115 at 4,000 RPM, then to run the boat at the same happy speed will equate to maybe around 3,200 with the 175, this assumes you dont go power mad and want to let it stretch it's legs, and lets face it, you will!

[Jarrah Jack]

Scott's are very frugal minded people. You only have to see those Scotts wearing kilts in that ad on the building site to understand how they are. Couldn't imagine them hooning around at full noise in a kilt , especially.:o

Presume Ozscott is much the same.;D

[Crocodile]

Hello Ozscott,

Chew on some of these figures.
http://www.yamaha-motor.com.au/sites/yamaha-motor/files/Haines_Hunter_V17_Legend_115.pdf
4000rpm 23 knots 5.7 gallons/hr 4 nautical miles/gal

http://www.mercurymarine.com/engines/engine-tests/boat-house-bulletin/?ID=502&92338.99344734623
3000rpm 22.6knots 3.75 gallons/hr 6 nautical miles/gal
4000 /30.5 /6.6 /4.6
All corrected for litres, kilometers/hour, US gallons to Imp gallons etc.

I know that the Seafarer is lot heavier than a 17' Haines but the results will not be too different.
Seems like a lot of trouble + $$$$ to go to get modest improvement in range.
If you get the bigger motor you will use the extra speed whenever you can, the nmpg figures 115 @ 4000 versus 175 @ 4000rpm are about the same, going a lot faster but mpg is what matters here.
This is a harsh one, you may be over-capitalising on that old boat.
I too have an old boat and wrestle with costs etc.

[fisho8]

I have the 175 Opti I have filled my boat up to the full 200ltr mark when I bought it and on the 5 trips I have had in it I am still on the same tank of fuel. I have travelled in and around the Bay and done about 5 trips from Scarbrough marina to Mud island running at 4000rpm and doing a few full throttle runs which I can say coming from a 115 opti was giddy up and go you good thing haha. As said it is easy to get carried away but my fuel guage still reads 120ltrs sitting level on the trailer. My 115 Opti was awsome on fuel and I would be lying if I said that this engine was better. Your Decision in the End Oz Scott good luck mate.

[ozscott]

I really don't use my boat enough for fuel running costs to be an argument. For longer trips I could use my 2 tote tanks (both 25 litre). So 200 l all up. Same weight as no totes and the extra weight of opti and bigger batteries. I would use the extra speed too. You guys are right. Now I am happy to cruise at 45kph but with the big opti v6 that would be 60. The yammy v4 I dare say would have more torque than the 3 cyl 115 opti but yep a move from the v4 to the v6 would be a big jump in grunt. My yam has a lot less hours than this opti and has always been well cared for. I know my motor which is a big thing. Cheers and thanks