200 Mercury 2.5L opinions
 

I found a pair of 225 Optimax engines locally for sale for $3500 each. I only need one for the V but need some thoughts on how the Optis perform. I know it is heavy at 497lbs. I know they are DFI. But talking with the marine mech instructor today at school he said they are prone to predetonation. Is this a problem with them? They are 2002 models hours unknown. The dealer will back them with a thirty day warranty which is useless because my v is too far apart to run it. Any advice is appreciated.

I would go with an 04 or newer if it was me. Up to early 03 they still had quite a few problems with the OPTI's.

I see a bunch of those motors running around here, Biggest key to keeping them alive is good gas, the good DFI oil($$$), and running ring free or carbon guard in each tank of fuel. Those motors are heavy, but they are fairly fuel efficient. Biggest draw back to the opti's are the stuff on the outside of the block(compressor, fuel pumps, injectors, sensors, etc) can cost more to replace than the power head itself. Look real hard at the pivot shafts and steering arms on those motors, for that price, they probably came off of a kingfish boat with a couple thousand hours on them

I had a 2001 -225 Opti and currently run a 2003 -250 Opti. Neither have high hours,(600 to 700) the 225 was near trouble free, a harness replacement under warranty, a poppet valve after warranty and plugs for good measure at 500 hours. Always ran ring free and tried to keep non-ethanol in the tank.
The 250 is new to me, but the history has it as trouble free thru the warranty and a denied claim for a compressor replacement sometime shortly after the warranty ran out. As an XS motor it requires 91 octane or better, I mostly run 93 octane with 10% ethanol.
The compressor seems to be the weak link IMO but I have no personal experience there. I have heard of some coil issues from other owners.
X2 what Ferm said, The later ones are better. With the early ones you either got a good one or you didn't. Early on Merc was replacing lots of powerheads with less than 50 hours, if the Merc owners knew then what they know now, there would have been some litigation over the frequency of the compressor failures. Merc claims the Compressor has been redesigned.
The go-fasts are starting to warm up to the Direct Injected Mercs. Dave Bush has a Level 1 kit that hops up the 300xs Mercs. They are making reliable power at 15 to 20% over stated hp. The internals seem to be stout and they have thousands of hours of testing time running them hard on the dyno. The tuners seem impressed with what Merc engineers have come up with. (meaning they had to do some serious homework and testing to better what the factory came up with.)
I wouldn't shy away from one so long as it checks out. They are heavier than advertised by a touch. It would be hp a plenty for a V20 they are snappy and fuel efficient. Talk the dealer into 30 days from initial water test on the warranty. That would be the only fair way to ensure you got what you paid for.

Thanks for the replies everybody. Couple more questions. Is there any way to find out the hours? What controls do i need, digital or mechanical? And what about the oil injection system? Should i plan on removing it? Right now i am awaiting an answer on a loan from my credit union. I planned to purchase an outboard next tax season after rebuilding the V. If i get the loan it may throw a wrench into my rebuild plans and money. All depends on the payment.

You CANNOT remove the oil injection from a DFI engine. DFI engines inject the fuel directly into the combustion chamber, so NO fuel goes through the crankcase, only air and oil that is injected. Most newer DFI's inject the oil directly into the main bearings now to furthur reduce oil consumption, and with no fuel going through the internals of teh engine to wash the oil off they use even less oil. DFI's though are VERY picky about what oil you use, and should only use an ashless 2 stroke oil with carbon removing additives which means you need to run a DFI oil(conventional 2 strokes do not have the carbon build-up problems as the fuel going through the engine prevents it. OPTI's though also use the oil to lubricate the air compressor, so cheap oil will not only carbon up the engine, but will trash the compressor with it. MANY DFI engine failures are DIRECTLY a result of using cheap oil in them. OPTI's are not bad engines, aand neither are the FICHT's, but early ones did have growing pain issues as it was such a new technology. As for how to tell the hours, a MERC dealer can hook it up to the scanner and tell you as the ECM keeps track of how many hours and at what RPM's.

Thanks Ferm. I looked up the Merc Opti/DFI oil and found it for $26a gallon. Not too bad. Although amazon wanted $66 per gallon, had me scared for a minute. What about the controls? Are these digital or mechanical? I hope to do like Ridge said, and try to get my warranty after i mount the outboard. Then i will run the piss out of it. As you can tell i do not know alot about dfi. I have only owned carbed motors. So bear with me.

I believe most of the OPTI's can be used with the regular MERC cables and wiring harness's like the older carbed engines used. They also have hook-ups though for the smartcraft if you want to use the SMARTCRAFT guages and controls as well.

Looking at gauges already and i like the Mercury Flagship gauges. Smartcraft gauges are nice but dam that sounds expensive. Should know tomorrow about my loan. Is there any way to identify if a compressor has been replaced? I will be able to look at the engines next week, I may put a deposit on one and take it to a MarineMax and let them look it over and check hours, compression, etc.

I talked with some of the guys at marine mech at school today and i am beginning to think they are biased against MERC. So i decided to stop listening to them. :fight: Especially when they mentioned "pOptimax" :you: Before i knew it i was hearing bs about getting an OX66 or a suzuki. (i just bought a suzuki car and not impressed with it and its check engine light that wont stay off, so yeah, piss on suzuki, might even change my avatar back)

Early 150/175 OPTIMAX's earned the reputation OPTIPOP's for injector problems that caused powerheads to go left and right, and also early on MERC reccomended there regular oil which was found to have caused alot of issues as well. SUZUKI makes a DAM FINE outboard, so they are right on that one.