Yammie 150 4 stroke is this right?

[Tangles]

Been doing some research into some motor options, looking at either a yammie 150 4 stroke or the Yammie 200 4 stroke. Spoken to owners of both and got good feedback on both on what im looking at.

Leaning to the 200 as there is no 175 yammie 4 stroke which is what i would get if it existed. Seems that some say that the 150 4 stroke actually puts out 165hp or 167 hp at the prop. Is this right or just crapola?

I always assumed/expected that a 150 badged as a 150 would output 150hp not 167.

cheers
Mike

[Ally Jack]

Aigusto,

I haven't seen the spec sheets but apparently the 150 yammie 4 banger puts out 150hp at a lower revs than WOT, so it would make approx 165-167hp at WOT. Those that have them agree, they are a grunt machine, do a search on the hull truth you'll see what I mean.

You would think that 150 meant 150 wouldn't you, but there are standards and percentage ratings either side of the mark.
Like a Suzuki 140hp by what I've read only produces 128hp and the 225 Yammie 4stk is really only 208hp. why?????

Ally Jack

[Tangles]

Ill check that hull truth out, with a lower weight the 150 is an option.

It sort of makes it a minefield doesnt it, If your getting more than you bargained for, you win, less hp? well i wouldnt be happy. You think your getting the right horsepower for the boat and maybe your really getting less than what you should.

mike

[Black_Rat]

Are you getting a new BIGGER boat Mike ? A 1770 weapon ? ;D ;D

[black runner]

When you check motor specs also look at cubic capacity, bore and stroke. You will find that depending on the model some are "stretched" to produce more hp from the same block used in a lower hp model. The Suzuki 140 is an example of a lightweight low cc high reving (6200rpm) motor at 2044cc which doesn't produce much more torque than the 115hp at 1950cc.

Hp should be used as a rough guide in the first instance, then compare weight, cc, bore x stroke with reference to the rated capacity of the boat it is going on.

Hp is only a measure of work done/time. So for example a motor producing 115 hp @ 5500rpm would theoretically produce more hp if tweeked to rev to 6000rpm. It would produce no more torque however at the useful cruise rpm where you need it. HP great for marketing not so useful for the unwary buyer.

This is a simplistic but useful way of looking at the issue when comparing like types of motor. However modern features such as supercharging, variable valve timimg and fuel injection greatly influence torque and overall performance and need to be factored in to the evaluation.

Cheers

[cormorant]

What matters when it is all added up is HP at cruise revs as that is where your ecconomy and most of your distance is covered at.. Peak HP etc is all crap as unless you are racing it is only a number you motor is capable of.

With your current boat work out what revs you are pulling with your existing motor ( I assume it i propped right)

What revs to get on plane with full load ?
What revs for full planning cruise with full load?

Then look for torque , revs and HP graphs and work out your HP you are actually using at cruise, torque and the fuel flow at that revs. If teh new motor can't do that or better you will have to go up a size.

Shame there isn't exactly comparable graphs between manufacturers but you can create a reference table pretty fast or graph it yourself.

You are sometimes better off with a bigger HP motor that you run in it's sweet spot rather than a buzz box and vice versa depending on the boat , hull and application.

The 10% rule on HP by manufactures under or above sticker label has been around for years in US and we have adopted it . The way they measure the weight of motors is the other industry joke but that's another whole story and all marketing bull.

[finga]

Are you getting a new BIGGER boat Mike ? A 1770 weapon ? ;D ;D
Or it'll make theircurrent boat go just a tad better.
Well better then the electric anyways ::)

And yep, it would be a minefield buying a new motor especially one on the upper end of the market considering the money they're worth.

What boat are you considering matey?

[Malcolm W]

The August 2007 overlander has an interesting comparison of motors in 2 prado's. A 127kw diesel and a 179kw petrol and its not until 3500 revs that the 179kw petrol catches up to the 127kw diesel. At lower revs(@2500rpm 106kw v 90 kw ) and with the big torque difference of the diesel it was way out in front for power. If these 2 motors were in a boat you would think the 179kw motor had a huge advantage.The only time it had any advantage was when it was at very high revs. We can get torque figures for cars but not boats? This would help a lot in choosing a motor.

[Tim_N]

When rating engines, companies are allowed a 10% leeway, meaning a 165hp outboard can be sold as a 150 hp ie 10% difference. Similarly a 140hp only needs to produce approx 126 hp to be sold as a 140 hp ie the early Zukes. So, yes, the 150 hp Yammie can and will produce up to 165-167 hp, it is all above board.
If I remember correctly, the Yammie is a 2.7l Opel engine and they could not dyno it down any lower than 165 hp, but at its lower max rpm range it was producing 150 hp.
I also think, and I may be corrected, that Foxy re-powered his cat with 2 of these and now it goes like buggery.
I hope this helps.
Tim