Reviews on 2013 Yamaha 4 stroke high thrust?

[mr-canada]

Originally Posted by Ian R

quote

"The new 2013 model is 20% smaller and lighter than the 2012 model and the extra long shaft version (25") would be 5" deeper in the water than the 20" i have now which would reduce the periodic cavitation i experience here when the winds pick up to 30 kts in the vortex at the entrance to the channel."

The 2013 model is not a new model as far as I can see, it's the same as since 2008.

On yahamha marine they show a diagram of the 2012 vs 2013 in size and say its 20% lighter. Guys on a diy sailboat builder site are complaining that it doesnt fit the same as the 2012 in their motor well and yamaha took their complaints into account and are going to release a limited run more of the ones on the 15hp block but only in blocks of 10 by pre order from japan.

A guy here has the 2013 its much smaller, they have been doing pretty good at cutting the size of their 4 stroke portables. I see some here at the yacht club from each generation, id say the 2013 is half the size of one from the 90s.

Extra long leg 25" weighs 118#

I think that they switched to the 8hp block because the epa or some us lake authorities or certification body complained that guys were doing the $40 carb swap to bump up to 15 hp on lakes that restrict to 10hp only and because registration is required above 10hp they were probably taking a hit on guys who were paying less for more of an engine as well. With the 9.9 on an 8 hp block nobody can overpower and avoid registration. My guess.


Lighter is better imo anyway

[mr-canada]

High Thrust | Yamaha Outboards

Link for t9.9

[Ian R]

Originally Posted by mr-canada

High Thrust | Yamaha Outboards

Link for t9.9

The weight and specs. in the link are the same as my 2008 model. They say a recent redesign reduced the weight by 12% . It depends on what they call recent. Can you link to the 2012 verses 2013 model .

[mr-canada]

Odd. There is a diagram to the left side of that page showing the 2013 t9.9 vs its previous design. All i can tell you is there are some of the previous design here at the yc and a 2013. The 2013 t9.9 is smaller than my 8hp two stroke (which isnt a fair comparison for the two stroke as its a 80s vintage).

I will try to post some pics to show the difference, if my tablet will let me post pics to the forum.

[mr-canada]

The motor on the blue boat with the propane cylinder is the 2013. The second one is a previous 2008-2012 model. The last shot is for reference, a previous design of unknown age, probably 90s or early 2000s.

Hopefully the order comes out right or i may have to clarify which is which further.

It may be hard to tell from the pictures, but the 2013 is noticeably smaller.

[mr-canada]

A further reference, this 8 is larger than the 2013 t9.9 as well, a 2008-2012 model as well

[Ian R]

I found some info in this link.FT60 / FT50 / FT25 / FT9.9 / FT8 2013 Techspecs - Marine Engines - Yamaha Motor Europe

The new model may be smaller but the weighs only 1 kg. less than my 2008 model. I'm disappointed the charging output hasn't improved , the specs say 6 amps, I've haven't measured more than 4 amps from mine.

[colemj]

The 6 amps will be at the max rpm - you probably haven't been measuring there?

Mark

[mr-canada]

Heres a question related but on a different tangent.

Part of the rationale behind getting the 9.9HT instead of a smaller engine (boat unloaded bare is 5600 lbs, fully loaded prox 7000 lbs) is because with a new (*reliable*) motor i would have confidence to motor for longer periods (and 4 stroke runs less gas, queiter, less smelly than my two steoke) so if i was feeling too lazy to pop up sail or if the wind wasnt optimal i could just fire up the motor and be done with it.

Ive heard around the YC and online that idling the motor (in gear moving forwards) os bad for the motor. However, it is most fuel efficient to putt along at low rpms. Balls to the wall will hardly push the boat much faster than say 50% throttle and waste three times the gas and putting along at idle or a high idle will get me 5 times further per litre of fuel than balls to the wall.

Im no motor mechanic but afaik if the impeller is pushing water through at the proper rate and you are using relatively clean gas (less impurities) why would a four stroke foul the plugs and rings? With a two stroke this is self explanatory because of the oil in the fuel but youd think a four stroke running straight gas could run forever at idle without issue, especially a modern engine that is probably fuel injected (im not sure if the t9.9 is injected but im guessing it is)

A sideline question but seeing as that capability is one of the things im looking to get out of this engine its worth putting into this thread for googlers hunting for info about this engine later.

[Ian R]

I run my motor at about 33% throttle and average 1.3 litres/hr. I vary the revs and use full throttle occasionally ,no sign of any problem after 800 hours.
These motors are not fuel injected.

[Ian R]

Originally Posted by colemj

The 6 amps will be at the max rpm - you probably haven't been measuring there?

Mark

The amps didn't change with rpm as I expected, maybe with a large load it may put out 6 amps at a lower voltage.

[susswein]

I'm considering buying a used yamaha 9.9 with the 25" shaft. I haven't seen the motor yet, but it's a late 90's or early 2000's vintage.

Is there any way to tell by looking at it whether it's the high thrust version or not?

[a64pilot]

A four stroke will tolerate relatively low load very well, you don't want to idle it necessarily, but many thousands of outboards spend millions of hours trolling for fish without harm. If run at low RPM excessively a four stroke will "make" oil, it's fuel dilution and not a good thing, so keep any eye on oil level and if it starts increasing, turn up the power a little.
Your absolutely right, high power gives very little speed, but a huge increase in noise and fuel consumption.


Sent from my iPad Pro using Cruisers Sailing Forum

[a64pilot]

High thrust motors that I am familiar with are immediately apparent, the prop just looks too big when compared to other regular motors, may not be true for all?


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[Rapanui]

I have had 3 different Yamaha 9.9 HT on previous boats and they were brilliant. Quiet, efficient, no smell and real value for money - engine, transmission, stern gear and prop all for less than £2000 GDP. If I could fit 2 on our current boat I would - far better value than 2 Yanmar saildrives.
Our last was on a 32 ft cat and a number of times we had to motor all the way to cross the English Channel ~70 nm @ 5kts using about 6 UK gallons. We also brought the boat up from the South of France via the Canal du Midi to Royan entirely under engine, all day long at 4 kts for 2 weeks. The only problem we ever had was at the beginning of the season the engine would not idle properly, cutting out as you changed gear. Easily fixed by removing the slow running screw and blowing it out, probably fuel gumming despite draining the carb.
We had it set up so that the engine steered with the rudders when down (lifted when sailing). That made the boat 32 ft x 17ft 6in a joy to park and the high thrust prop really worked in reverse unlike previous 2 strokes which were less than feeble in reverse.
Apart from normal oil changes etc, I would run the engine in a big dustbin with fresh water for about 2 hours at the end of the season and at the start to flush the waterways clear and dissolve salt. Then take off boat and into workshop for the winter and oil changes etc.
It did provide some charge to the batteries, but that was a bonus and you do need alternative charging for anything more than occasional very light useage. We had solar so it did not matter.
All in all, a great bit of engineering.