1998 225 Optimax Advice

[BayHouse]

Folks, new to this board and appreciate your help in advance. I'm looking at a buying a boat with twin 1998 225 Opti's with ~315 hours. The engines are original on the 1998 hull and have seen very low use. The hull is in great shape, supporting the low hours claim.

BUT.....there is a lot of noise on the web about the Opti's. Some have had a lot of success/love, others failure/misery. I have received mfg. info from another poster on the engine S/N and very little maintenance has been logged on the engines.

In another post, I read "you should make sure he is using the blue air injector's, the solid black and black with blue dot were both recalled" - is this universal truth for every 1998 Opti or just some? Where are the air injectors on the engine?

I haven't done a compression test, that is the next step before an extended sea trial
.
Any other words of advice before I take this purchase further? Don't want the seller or me to incur any unnecessary costs.

Thanks!

[gregpro50]

The biggest issue I have seen with the older optimax is air compressor failures which clog up the air injectors, causing the cyls to run hot, causing the motor to blow.

[BayHouse]

The biggest issue I have seen with the older optimax is air compressor failures which clog up the air injectors, causing the cyls to run hot, causing the motor to blow.

Does the air compressor just fail or does it die a slow death? Any way to diagnose the performance of the compressor, kind of an early warning alert?

[gregpro50]

It can go both ways. Catastrophic or slow. The compressor is water cooled and if you suck up some junk and the water intake for the compressor gets plugged it can overheat. The metal shavings then go right into the air injectors plugging them up which is bad.

You can hear it when the bearings start to go or pull the belt off and wiggle the pully to see if it has any play.

I did alot of research before I got an optimax and it seems the compressor is the achilles heel.

[BayHouse]

You can hear it when the bearings start to go or pull the belt off and wiggle the pully to see if it has any play.

I did alot of research before I got an optimax and it seems the compressor is the achilles heel.

Great advice, added this suggestion to my pre-buy check list. What year engine did you buy and has it served you well? Did you have any fuel rail issues?

[gregpro50]

I have an 05 Mercury racing 250xs with 110 hours. No issues so far. Runs great. Lots of power and easy in fuel.

[merctech5591]

I personally would stay away from the older optis and try to find a 2002 and newer opti. It will have the Motorola computer and have all the updates . If the motors have the older style Injectors u at looking at almost 2500 in injectors alone.

[pwrman]

to many compressor issues, 12 years later a real fix.

[sosmerc]

to many compressor issues, 12 years later a real fix.

And what, was the "real fix" ???????

[Scmarineperformance]

And what, was the "real fix" ???????

the real fix was to make the replacement compressors in usa using two main bearings on the crankshaft as opposed to one

[gen2flight]

compressor design improvement for sure. My gen2 200xs ros uses the NEW compressor but it was made in mexico. I,m sure merctech 5591 has your best interest at heart, upgrades in computer controls/diagnosis, injectors ect. Not sure that a new compressor fixes other potential trouble spots.

[Glasply150]

I wouldnt bother with the older optimax's. Especially the 98/99 years..They were brand new at the time, injectors, compressors, reeds, they've all been updated since then. Like merctech said, Try to get an 02 and above, there just a more dialed in motor.

[cali kid]

Early opties were called optipops.Many upgrades later, great motors.02s are good Big change in 03 04.Red filter vst motors.Even better.~ Randy