New lightweight F70 4 stroke coming

[Tim_N]

Just done a Google search for my next engine, which I would like to be a Yamaha 4 stroke after being sooooo happy with my current one.
I had heard along the grapevine some time ago that a new 70 hp 4 stroke was being developed but at last, and this will please you cat lovers, the new F70 should be released about Easter next year.
As far as weights go, it tips the scales at approx 118 kg, so bring them on.
That's only a few kg's heavier than my current F50.
Mmmmmmmmmm, horsepower.
Tim

[Jarrah Jack]

Nearly 40kgs lighter than my df70...Thats a massive amount...makes you wonder where all that weight came from....If those techs could do the same with people they wouldn't have to build engines.

[deckie]

gawwd...great news and perfect for me. Just what i wanted.
BUT
do i wait ?....took the motor off and after the refurb she's about ready for a new donk NOW.
Ahhh...i wanna go fishin again 8-)

Plus i dont like to be the guinea pig for brand new anything like cars and motors. Whilst i rate Yam top of the tree for reliability i hate the idea of any recalls and might be best to wait for a late 2010 model for any small quirks to be ironed out and be as bulletproof as their others.
pfff..decisions decisions.

[Noelm]

it may be lighter because it is an upgraded HP of a lower range (as in a 50), but if it's not, then maybe a (say) 80 or 90HP maybe just around the corner using the same basic motor, if you get what I mean.

[FNQCairns]

it may be lighter because it is an upgraded HP of a lower range (as in a 50), but if it's not, then maybe a (say) 80 or 90HP maybe just around the corner using the same basic motor, if you get what I mean.

Yes! pretty much by the specs of these ultra light outboards this is pretty much what they are up to even if the motor is a new design.

Now if they published the torque specs along with the Hp that would be nice, otherwise the first 1000 owners will be walking the wilderness until the grapevine decides what the engine is actually about.

What's the true use of say an 10 extra HP if it can only ever push the same pitch (or less even) than the heavier 60 and all the while doing it harder with more stress.

chersfnq

[Jabba_]

Well if I can say this with out getting flamed... The Fact that BRP shit-canned Yamaha in there promo video's has got Yamaha off there backside and produced some 4st that going to rock the boating world... It's something you can thank BRP for... They stired the sleaping giant, and now every DI 2st is going to have there but kicked by 4st in all aspects from economy, weight, hole-shot and top speed and posibly engine torque... Economy has all ways been them for the 4st, but the performance has always been lacking....

The worm has turned and the DI 2st manufactures have been caught napping.... Now it's time for them to raise the bar in the way off performance, economy and light weight high performance engines that are as reliable as the 4st....

[finding_time]

Well if I can say this with out getting flamed... The Fact that BRP shit-canned Yamaha in there promo video's has got Yamaha off there backside and produced some 4st that going to rock the boating world... It's something you can thank BRP for... They stired the sleaping giant, and now every DI 2st is going to have there but kicked by 4st in all aspects from economy, weight, hole-shot and top speed and posibly engine torque... Economy has all ways been them for the 4st, but the performance has always been lacking....

The worm has turned and the DI 2st manufactures have been caught napping.... Now it's time for them to raise the bar in the way off performance, economy and light weight high performance engines that are as reliable as the 4st....


Well hallelujah brother!!!! Thank the good Lord for BRP!!!::) ::) ::) ::) ::) ::) ::) ::) ::) ::) ::) Do you really believe some of the crap you type Jabba?:o

Ian

[Jabba_]

Not saying BRP are solely responsible for Yamaha's improvements, these improvements would off happen sooner or later, but they have come sooner then anyone expected and much better then anyone anticipated and I believe it is because BRP pissed all over and ridiculed Yamaha with there promos and advert's... The fact at the time was Yamaha was an under performing motor.. Reliability was outstanding, but there performance was so boring and they were heavy... Even the the Yamaha dealer close to me was shocked at the spec off the new SHO and put's the radical improvements down to yamaha wanting to belt the crap out off BRP for there insult towards Yamaha...


Also there is going to be a bit off a wait to get these new SHO and Off-shore motors.... They should be in the Australian line by the 2nd quarter next year

[whatscracken]

So I guess Yamaha could also thank BRP for being number one in market share with around 35%. It can only get better the longer the E bombs are around

[cormorant]

Will it be released in other markets first or are Aussies the Guinea pigs ?

Camchain or belt and what are the total ongoing costs is what we all should be looking at along with expected life.

Like others I have given up getting excited about new motors till they have proven themselves and I have seen em apart on a bench.

The real test for a lot of motors is the infrequent use so may get and I'm not sure how manufacturers test that except with accelerated weathering tests as slight rust in bores from lack of use due to open ports etc kills more motors lifetime than anyone can count.

Noted the other day that when putting the Honda pumps into winter mode they are suggesting a particular crank position to stop moisture ridden air when stored. Not sure this works with twin and more cylinder motors as one pot will always have a open port.

2 strokes had a oil coating but I am not sure if the now oils are really good at leaving a film in the cylinder. Perhaps they need a storage mode or a airbox and exhaust plug.

[FNQCairns]

Will it be released in other markets first or are Aussies the Guinea pigs ?

Camchain or belt and what are the total ongoing costs is what we all should be looking at along with expected life.

Like others I have given up getting excited about new motors till they have proven themselves and I have seen em apart on a bench.

The real test for a lot of motors is the infrequent use so may get and I'm not sure how manufacturers test that except with accelerated weathering tests as slight rust in bores from lack of use due to open ports etc kills more motors lifetime than anyone can count.

Noted the other day that when putting the Honda pumps into winter mode they are suggesting a particular crank position to stop moisture ridden air when stored. Not sure this works with twin and more cylinder motors as one pot will always have a open port.

2 strokes had a il coating but I am not sure if teh now oils are really good at leaving a ilm in the cylinder. Perhaps they need a storage mode or a airbox and exhaust plug.

I read where Tohatsu did a test for just this and tcw3, in that test premix 50:1 is good for around 3 months and oil injected for something like 1 month.

Tcw3 has a good dose of anti rust inhibitors.

cheers fnq

[Jabba_]

Will it be released in other markets first or are Aussies the Guinea pigs ?


The US first then Australia will get them around April - May next year...

[Tim_N]

And I think, if the grey matter is working correctly, that the Google search told of how the new F70 had been a result of 3 years R&D, so I'm guessing it won't be a throw together, half dodgy job if it is wearing the Yamaha badge.
The Yamaha guys I know from HQ, have know anbout the need for a lightweight F70 for a very long time. They tried several configurations many years ago eg twin cam F60's pulling 70 hp but at 7500 rpm, hence the need for a all new re-designed from the ground up state of the art engine.
The big boys usually don't muck about when bringing something new to town, however, time is the best judge.
Tim

[skipalong]

Tim nothing but yamaha for me :P youll love it, you know why :)

[Lovey80]

It won't be long now for those 5.2kc owners will b bolting on sub 120kg 90hp engines.

[Mr__Bean]

It won't be long now for those 5.2kc owners will b bolting on sub 120kg 90hp engines.

Aw gawd.......

Then we would never shut them up!!!

- Darren

[boatie_72]

The new F70 is a further development of the F60, sharing the same displacement and stroke. Yamaha said the engine is lighter than any competitive four stroke, or direct injected two stroke motor in the 70 - 75 horsepower class. The F70 achieves this by its unique four valves per cylinder design activated by a single overhead camshaft rather than the conventional dual camshaft design for 16 valve engines. This reduces the weight that would result from having an extra camshaft and the components that go with it.
Four valves per cylinder have dramatically increased this engines volumetric efficiency - the efficiency with which the engine can draw fuel and air in and push exhaust out of the cylinders. Increasing this efficiency means the F70 is able to run at a higher RPM with the max operating RPM being increased to 6300rpm.

[hivalley]

I like Yammies, I have two of them at the moment, but what a useless motor this would be for boating applications. Running to 6300 RPM to make 70 HP is a rip off to the buying public. This motor will have no hart at all.

You need TORQUE in a outboard as you do not have the luxury of multiple gear ratios as in a car. We should look past the BS HP figures and look at the Torque figures when deciding if a engine is worthy.

Lets compare the new Yam to everyone's favorite ::) the E-Tec. As Evinrude don't have a 70 HP lets look at the 60 & 75 HP Evinrudes.

Yam F70 - 6300 RPM - 50 lb-ft

E-Tec 60 - 5750 RPM - 54 lb-ft

E-Tec 75 - 5000 RPM - 79 lb-ft

Sorry Yamaha this is not your best.

[FNQCairns]

Couldn't agree more! simply lighter and less fuel on average has never made for a better outboard engine, the current crop of lighter 4st engines are not/will not be good engines. They are shiny and marketed as replacements for what existed before but they are not.

They do make great engines fill a nich outboard fitment where the regulated weight only might exclude a slightly higher outboard HP if it was wanted, particularly on twin engine setups. Here they 'just' might work.

In virtually all other they simply will not when compared apples to apples what they replaced ie the heavier, bigger displacement, thirstier on average and better outboard.

cheers fnq

[Tim_N]

What site can we view the torque figures people need to know about?
Tim

[FNQCairns]

Tim it's a pretty simple equation for any NA engine. you can also estimate HP at points along the rpm scale to make your own torque curve. Most engines follow the same basic rules.

There is a good reason why people always say pick the one with the biggest displacement, it's because that one will usually make its maximum HP lower in RPM ...= better Torque often grossly better torque throughout it's usable RPM.

Calculators here:

http://www.google.com.au/#hl=en&source=hp&q=hp+to+torque+calculator&meta=&aq=1&oq=hp+to+torque&fp=2623657aecaa0d97

cheersfnq

[hivalley]

Hi Tim,

I dough you can find Torque / HP curves on the internet, most outboard manufactures don't want us to know the truth.

There are a few Evinrude E-Tec torque curves published for advertising purposes as they produce 2 strokes only so it;s great advertising. All other manufactures have a stake in predominately promoting there 4 stroke line of engines so it is not in their interest to reveal inferior torque values for the same HP engine.

But mathematics stuffs it up and removes the BS , HP to Torque or Torque to HP is a very simple mathematical equation.

How to find the HP
Horse Power is simply [TORQUE] times [RPM] divided by [5252]

How to find the Torque
[5252] times [HP horse power] divided by [RPM] = TORQUE

Hope this helps.

[Noelm]

that may be sort of correct, but it is not always true, too many things come into play as well, HP and torque can be changed by various methods, to make an engine much better for an application, the RPM range can also be changed to suit, cams, stroke and bore valves and ports all influence torque and ultimately HP as well, but it is not a hard and fast maths equation.

[hivalley]

that may be sort of correct, but it is not always true, too many things come into play as well, HP and torque can be changed by various methods, to make an engine much better for an application, the RPM range can also be changed to suit, cams, stroke and bore valves and ports all influence torque and ultimately HP as well, but it is not a hard and fast maths equation.


Sorry mate but it is only hard and fast maths. Same old formula by a guy called James Watt.

PS. James also made a Steam Engine.

[FNQCairns]

that may be sort of correct, but it is not always true, too many things come into play as well, HP and torque can be changed by various methods, to make an engine much better for an application, the RPM range can also be changed to suit, cams, stroke and bore valves and ports all influence torque and ultimately HP as well, but it is not a hard and fast maths equation.

No not really Noelm remember we are talking outboards here, even the Verado which is the only forced charge engine i know of, it too will follow the rules because by the very nature ot the beast (outboard motor) for reasons outlined above it must! ie the supecharger does not 'come on' at 5000prm and the max hp at whatever claimed RPM is a specific and induvidual number.

Even outside of outboards it remains a no not really.

I don't want this little bit but very important piece of outboard consumer understanding to be sidetracked by fluffy remarks, serves noone.

cheers fnq

[Noelm]

OK, fair enough then.

[fatovich]

That shows the torque at that particular RPM, unless published or tested on a dyno the torque figure at any other RPM is a guess.

[Noelm]

that's beause that's where they develop the max HP?

[FNQCairns]

That shows the torque at that particular RPM, unless published or tested on a dyno the torque figure at any other RPM is a guess.

So what you are saying is that any useable engine that has say 60hp at 5800 might spike and create it's 60hp once or multiple times somewhere earlier on it's way it max rpm?? say 3500rpm then 4500rpm then 5300 ?.

Consider reading back or do some googling, the torque can be ESTIMATED well enough on it's way to known figures on all like engines that are usable anyway...especially as an outboard it will have very similar and common curves to other already known torque curves.

There is nothing new about how engines make torque and power, the best we have is variable valve timing but still it is small potatoes, turbo's only change the rules enough to make a big difference if they are designed to spin up late a little bit like i guess nitrrus oxided.

The designers of these new lighter low displacement outboards knew almost exactly what torque and hp it would be creating at every rpm and all before the new engine left their computer screen.

cheers fnq

[Tim_N]

Anyway, there is a lightweight F70 coming, but thanks for the info on torque, that is really good info.
Tim

[Noelm]

OH yeah, forgot about the original question/statement, kind of happens on here, but most is good knowledge sharing and fun, but sometimes the fun can get a bit intense.

[hivalley]

Tim, good luck with your new Yammy, I hope all goes well for you. I do like Yammies mainly the 2 strokers, fantastic reliable engines. I had one four stroke and sold it, it was a disaster, maybe things have changed a lot since then. From your original post it looks like you are going from 50 to 70 HP, that is always fun to power up.

Let us know how your rig performs, after you prop and run her, you can't beat real world tests to know if you are happy with your choice, keep us posted.

[FNQCairns]

OH yeah, forgot about the original question/statement, kind of happens on here, but most is good knowledge sharing and fun, but sometimes the fun can get a bit intense.

Only sort of yet again, it's easy to sit at a computer and and cast unreasonable doubt over such a solid principle but when the party's over som poor bloke may well be left holding the bag based solely on that doubt.

To some these new small displacement high hp engines - depending on what they are coming from and why, will find themselves quite unhappy and seriously out of pocket, empathy will stop a party in it's tracks.

cheers fnq

[honda900]

A lot of this light weight high horspower engine specs are coming from the motorcycle industry who have been working on the same principals for years, how can we lighten the engine and devlop more horespower.

Take for instance the bike on my avatar, they have the same block as the an earlier version but reworked the internals, longer stroke it develops much more torque in the bottom end than the old bike (honda 900) sure they rebored it and increased the cubic capacity as well.

Yes I agree that most of the engine horspower is delivered in the high end of the range, but the bottom end of the new 1k bikes is unbelievable different from older models, torque off the line finally.

Yamaha, Honda, and Suzuki, have been working on these for years, Probly now translating some of the technology to the marine industry.

210 hp out of an 800cc engine is pretty special. Funny though the 800's are now faster than the 1000's simply because of too much horsepower.

http://www.highrevs.net/motogp-bikes/yamaha/yamaha-yzr-m1-2008.php


Regards
Honda.

[fatovich]

So what you are saying is that any useable engine that has say 60hp at 5800 might spike and create it's 60hp once or multiple times somewhere earlier on it's way it max rpm?? say 3500rpm then 4500rpm then 5300 ?.

Consider reading back or do some googling, the torque can be ESTIMATED well enough on it's way to known figures on all like engines that are usable anyway...especially as an outboard it will have very similar and common curves to other already known torque curves.

There is nothing new about how engines make torque and power, the best we have is variable valve timing but still it is small potatoes, turbo's only change the rules enough to make a big difference if they are designed to spin up late a little bit like i guess nitrrus oxided.

The designers of these new lighter low displacement outboards knew almost exactly what torque and hp it would be creating at every rpm and all before the new engine left their computer screen.

cheers fnq

It is theoretically possible ;).

There are a lot of different shaped torque curves out there and you cannot guess an engines characteristics accurately based on one data point. Otherwise why do we need to see a torque graph?

Do you know how much power this engine will deliver at 2500rpm? and if it makes less than a 2 stroke 70 at 2500rpm does that matter if it is geared/propped properly?

[Tim_N]

Just a question, where do I find out the bit about the F70 being a reworked F60, wouldn't mind reading that.
Please pass on a link that is beaut info.
Tim

[FNQCairns]

It is theoretically possible ;).

There are a lot of different shaped torque curves out there and you cannot guess an engines characteristics accurately based on one data point. Otherwise why do we need to see a torque graph?

Do you know how much power this engine will deliver at 2500rpm? and if it makes less than a 2 stroke 70 at 2500rpm does that matter if it is geared/propped properly?

Theoretically possible I dunno but it would be a good engine to own..imagine the torque at the first spike!

I agree there are all types of torque curves out there and all sorts of engines, to ensure caveat (gotta do that on forums..think ahead in answer;) ). I made sure I included stuff like "like", "estimate", "outboard", "basic" "apples to apples" etc.

Waiting for a 747 jet engines torque curve to make some obscure point::).

We need to see a torque curve because some engines might make say 90 hp with any combination of the following 4valves per cylinder V 2, 4st v 2st, 2cy V 8 cylinder, 1200cc v 5000cc, power valves V none, variable valve timing and any multitude of other mods or end design.

Outboards are outboards and are a constant throttle application a seriouly hard engine to design well and as such at our level of our technilogy V cost we have no special rabbits in the hat to pull out to change this equation but slightly....unless of coarse the 747 engine...but thats another story:)

Oh yeah yes you can estimate the output at 2500rpm it will not be accurate but it will be close enough, you need a like engine to compare to, that is one with it's max HP at rpm known and the rest of the engine like like, you can also estimate from speeds achieved on the plane and yes proping matter heapswithout reaching the engines full RPM you in theory never reach the engines full hp.

I dunno how this particulr engine does compare in it's CC to others of the same or smaller hp as I am not personally interested but without doubt there still is no subsitute for CC and also number of cylinders when wanting an NA engine on the back of your boat.

cheers fnq

[Tim_N]

So,
What is the better engine as far as torque and weight and displacement goes in the 60 to 70 hp bracket? Is it the eTec?
Tim

[fatovich]

Tim_N: Whatever works on your boat (for the price), a yamaha carby 2 stroke 70, evinrude 2 stroke di 70 and mercury 4 stroke 70 should all make the same peak 70 hp at whatever rpm is specified by the manufacturer. (as long as it is geared properly)

Technology is doing wonderful things with engines in the auto world, with DI (sometimes turbocharged) VVT four stroke engines doing wonderful things to economy in place of larger CC NA engines, they have better volumetric efficiency (better power per CC per RPM) than before and better emmisions and importantly very flat torque curves. It is only a matter of time before this tech makes its way into outboards and that is a good thing. Peak HP will occur at a higher RPM but that is not a bad thing as long as the motor is geared/propped correctly.

BTW I would probably go for the suzuki 70 in that hp if weight wasn't an issue, maybe the yammie 60 ht otherwise.

[FNQCairns]

Tim throw up the full specifications and pre calculated torque of each you are interested and we can have at it.

Just now I looked up the new Honda 90hp because i think i heard it was one of the new breed of light low CC engine, i calculated it's torque at 75! if my calculation was correct the 75 e-tec has more torque!!

IMO they are not all good engines, it's worth the investigation if spending the money.

cheers fnq

[hivalley]

I see the F70 is developed from the F60, sharing the same displacement and stroke.

One thing often overlooked is the HP reporting requirements placed on manufactures, that is HP must be within 10% of the stated.

Therefore the F70 could be 77HP or it could be 63HP or anywhere in between.

Most Japanese manufactured engines are usually on the low side, most US engines tend to the maximum allowable.

As we all know all outboard manufactures use identical bore and stroke combination over several HP ratings, when I choose an outboard I like the bottom of the range engines, that being the largest engine displacement for a given HP. I believe these engines are under stressed and ultimately more reliable with a longer service life.

Just my thoughts.

[Tim_N]

So when the eTec 75 runs at 5000 rpm and punches out 79 lbs of torque, it is more favourable than a Yamaha F70 which produces its hp at 6300 and punches out 54 lb of torque.
The 75 eTec is shared with the 90 hp and the Yamaha F70 is the same displacement as the F50 and F60. The eTec is a 1.2 l engine and the Yamaha's are a 990 cc engine.
The only downer is that the eTec is about 20 or 30 kg heavier, but my boat can easily carry that.
Fancy going to DI 2 stroke from a 4 stroke, who would have thought.
The Suzuki 70 is also shared with the 80 and 90 but is going to be around 40 to 50 kg heavier. It would be the pick of the 4 strokes then considering it is a 1.5 l engine. It produces its hp at 5000 to 6000 rpm, so assumming it is closer to 6000 rpm, its torque is 61 but if it produces its hp at 5000 then the torque is 73, excellent, so what rpm figure do I use?????
All good info and thanks to all for the input.
Tim

[hivalley]

Yes Tim, big strong engine components for modest HP at lower RPM will give a long unstressed life for a motor.

Weight is a downside, like everything it's a compromise.

[hivalley]

Tim, see the sample charts on page 2 of the link, they are typical of how 2 & 4 strokes plot, also how displacement affects things. Interesting read if you have time, although a bit dated but mostly still relevant.

http://members.iinet.net.au/~pauldawson/Iame24-4strokes.pdf

[FNQCairns]

So when the eTec 75 runs at 5000 rpm and punches out 79 lbs of torque, it is more favourable than a Yamaha F70 which produces its hp at 6300 and punches out 54 lb of torque.
The 75 eTec is shared with the 90 hp and the Yamaha F70 is the same displacement as the F50 and F60. The eTec is a 1.2 l engine and the Yamaha's are a 990 cc engine.
The only downer is that the eTec is about 20 or 30 kg heavier, but my boat can easily carry that.
Fancy going to DI 2 stroke from a 4 stroke, who would have thought.
The Suzuki 70 is also shared with the 80 and 90 but is going to be around 40 to 50 kg heavier. It would be the pick of the 4 strokes then considering it is a 1.5 l engine. It produces its hp at 5000 to 6000 rpm, so assumming it is closer to 6000 rpm, its torque is 61 but if it produces its hp at 5000 then the torque is 73, excellent, so what rpm figure do I use?????
All good info and thanks to all for the input.
Tim

A guess on the Zuk is the 70 will be rated at 5k and the 90 at 6k. this is pretty much the way the industry does it, the extra hp is never truly free when it comes from the same engine/block.

My pick of the ones you have thrown up is the Zuk the e-tec and then the yamaha. I would choose the zuk over the e-tec because I personally believe that on average typical 4 st technology over a 15 year wear and tear lifespan will be remain more cost effective.

A 1.5l engine producing 70 hp points toward a far more tractable engine and a flatter torque curve throughout it's rpm range than the (little screamer) yamaha.

The Zuk may also end up close in torque to the e-tec at all cruising speeds given the Zuk has 4 cylinders and the e-tec has three.

good luck

cheers fnq