Ok here is the scoop,

Lets say you have a boat 19'er, Tracker Deep V. Rated for a 175HP outboard. Boat is a 2001 model year.

Currently you have a 90hp Mercury 2 Stroke on it with low hours, very clean motor. Will push the boat at about 33 MPH.

You find a 175hp Yamaha ProV (1996) that you can afford. Will require upgrading/changing the cables, and the controls.

Do you do the upgrade to a 175HP, older "yamaha" motor? With unknown hours.

Do you wait a while longer, and upgrade into a 150-175HP Mercury Opti (2001-2005 vintage)?

Reality is that a brand new motor of this HP is out of the question. So how much difference is there between a 1996 Yamaha V/max, and a 2000-2004 Merc Optimax?

Are yamaha's all they are cracked up to be?

The motor would be purchased from a reputable TFF Member/ Dealer.

OK, Now I am ready, tell me what you all think.

compression check, computer read out for hrs. if possible, check the lower unit oil for metal and water, if all checks out (and it probably will if tffer). I say go for it. can't comment on yamaha or newer mercs. but if it checks out I say do it.

And let me know what you want for the 90...

is there anyone that can comment on a 1996 Yamaha vs 2001 Mercury, as far as maint/quality etc? I am a bit befuddled on this one, and I know there are some smart guys out there that have some good advice, I am all ears....

Yamaha makes some good motors. IMHO both manufactures are on equal playing fields. It just comes down to which one you like best.

What are you hoping to achieve by changing engines?
You might gain some speed by upgrading to the higher horsepower engine but your fuel economy will suffer. If you have to re-rig the boat for the Yamaha you will always run in to hidden/didn't think of that type expenses.
If you are willing to shop around you might find some huge bargains on "non-current" engines, I know Allison 1 Made a heck of a buy on a Opti-Max several years back and time are tougher now.

i'd lean towards the 04-05 mercury, until i got an idea about the condition/hours/etc on that older yamaha. you never know, the yamaha could be a great engine with reasonable hours, and if that's the case i'd go with it just to save money in the short-term.

I am really pondering this one, I am in no hurry to do this. It is more of a hypothetical than a reality at the moment anyway, as I dont have a boat picked out YET, and I am still in Afganistan. However, I think I have my next boat narrowed down to 2 or 3 today, tomorrow is another story. For the type of boat I am looking at I have not seen one that was matched HP for the MAX the boat was capable of. All 3 of them are in the 50-60% range of max recommended horsepower. I dont plan to use the motor other than to get to the fishin hole, then the electric TM or the 4 stroke kicker will be used, depending on conditions and type of fish I am after. Am I wrong to assume that a 175hp or a 200hp will get better fuel economy at 1/2 -3/4 throttle than a 90 hp at WOT? Even if I have to give up a little fuel economy, getting somewhere in half the time (weather conditions dependant) is worth something. 90HP I am being told will run around 33 MPH, 150 around 50 MPH, 175HP, 55 MPH, there is a HUGE difference in performance in running 55 MPH over running 33 MPH.

Lets thow another twister in there,

What about an EFI motor over a carb motor? Will the EFI run better/ more fuel efficient?

Can you pre mix fuel in the main tank on an EFI motor, or has the technology on the oil injection systems gotten good enough that you dont need to worry about it anyway?

Keep what you have and save your money for another time.

I'm not sure the costs and time is worth the difference in speed and power.

"If it ain't broke don't fix it." Bigger isn't always better. I have a 19' cc, max speed 38mph empty, I usually run about 30-33mph and that is plent fast for me. The only time I would want to go any faster is if I were going to make a long run, which I never have.

i heard the other day yamaha eliminatede 2 strokes from there line anyone esle heard this

If you go with Yammy or Merc. Get the HPDI Yammy or the Merc Opti.
Then fuel economy wont be as much of a concern. They use a LOT less fuel than the others....some say 40% less.

If the boat U are buying only has 50% of max rated HP on it, it's probably going to work harder and wear out faster.

Sound advice Bazz tex

Would a 1998 EFI merc be comperable to the OPTI?

NO. Difference is night and day.