YAHAMA ENGINES

Phil · Post by **Phil** » Wed Apr 30, 2008 8:14 am

WILL A YAMAHA HDPI GET AS GOOD FUEL ECONOMY AS A YAMAHA 4 STROKE ...........IS A HDPI LIKE A MERC OPTIMAX ????

kopper_bass · Post by **kopper_bass** » Wed Apr 30, 2008 9:16 am

Jigs,
I love my Yamaha HDPI - its extremely reliable, loads of power, and just intimidating on the back. I would not hesitate to buy another one, if we could in CA.

But, the one adjective i wouldn't use to describe it is "gas efficient".
At low and moderate speeds, it consumes the same as an Optimax, and does moderately well! But at high speeds and surely WOT, it eats at a faster rate than the Optimax; both gas and oil. Not too extreme, but surely more.

I can't speak for the 4 stroke on a bass boat but certainly, 4 strokes dont eat oil, so thats always a plus. i do know that the saltwater guys really love them and they are becoming the engine of choice; both for reliability and efficiency. They of course dont run at WOT like we tend to do, so it stands to reason that they get good mileage. But my friends who all have them on their saltwater boats say they still consume less than the traditional 2-strokes.

Hope that helps you,

Kopper_Bass

Kopper_Bass

Dave Wilson · Post by **Dave Wilson** » Wed Apr 30, 2008 6:31 pm

Re: Optimax engines: My Pro XS uses less fuel than my regular Optimax- this is pretty typical. The XS also uses less oil.

Rex · Post by **Rex** » Wed Apr 30, 2008 9:40 pm

Yamahas LOVE oil at WOT, seem to do better by far at 5000 rpm or less. Fuel-wise, same deal.

parker · Post by **parker** » Wed Apr 30, 2008 9:48 pm

the HPDI i had was not very reliable for me at least
I had quite a few issues that arose with it
motor housing (I dont know what this is called) wouldn't stay on
for a period of time it wouldn't go into reverse
when running it got a little faulty at higher speeds
and it is very loud
(this was on a bay boat in saltwater)

now running an opti max pro xs on a bass boat in my opinion the opti max is much better

SloppySeconds · Post by **SloppySeconds** » Thu May 01, 2008 11:15 am

Take a look at some of the performance bulletins on the Yamaha website. You should be able to get a good comparison between the two. I think that at WOT, the 4-strokes will consume just as much gas as the opti's and HPDI's... except no oil. At "normal" cruising speeds, the 4-strokes tend to do a bit better - especially in the smaller horsepower motors like 115's, 60's, 90's.

I've been running a Yamaha 150 4-stroke at work for a few years now. It's bombproof and gets good mileage. We've also got a VMAX 150 HPDI and a carbed 150 VMAX - both good fast motors, but not as good with the gas mileage.

I wouldn't hesitate to get a 4-stroke. You may lose some hole shot, but you'll make it up in reliability, gas mileage, oil cost and longevity.

Jason Milligan · Post by **Jason Milligan** » Thu May 01, 2008 1:04 pm

Maintainance on a fourstroke outboard is horrible. You have valves that need to be adjusted, timing chains that stretch and need to be adjusted and or replaced, etc... Paying for two stroke oil sucks too though.

M. Warner · Post by **M. Warner** » Thu May 01, 2008 2:17 pm

I have a zx 225, (skeeter) with a 225 hpdi, I ran for 40mins two ways, 80 mins total at wot, used alot of oil, but I used just under a half of tank of gas, and the second day did the same thing but in 4 foot rollers both ways and used the same amount of gas , just under a half of tank. I have had guys in my boat saying that it gets great gas mileage compared to there mercs. I am not sure about that, I have only owned a yamaha, and have never had one problem with it. I love my skeeters and the yamahas.