Mercury XRI 175 2.5 question....what makes it 175 versus 200?

[LdyAv8r]

1986 2.5 XRI 175 OD137199 completely stock. It has laser injection complete with factory fuel sump, oil injection ect ect.

What makes this engine a 175 versus 200?

Would I see any benefit from bolting on the intake, carburators and reeds from 2.4 200. That 2.4 really screamed before it overheated and blew from stopped up waterpickup

[Terry Jackson]

The 175 had a medium length tuner, the 150 a long one, and the 200 the short bell shaped tuner. There was also a different divider plate between a 150 & 200, but I can't remember which one was on the 175. Also 150 was iron sleeves, 175 & 200 had chrome bores.

[pyro]

If it's a 1986 It's not a 2.5

The 2.4 motors were chrome bore...

If memory serves me correct, the first Mercury EFI motor was the Laser "220" XRi in 1987. I think it was the only EFI model in '87. I don't recall a 175 XRi being made until '88 or '89, but they were still 2.4 litre motors.

You might have a mixed-bag motor on your hands, or possibly just a different cowl on the motor.

Can anyone run his serial number?

The EFI system is fine as long as you have a good battery and the TPI is kept properly calibrated. It will idle nice, it will not load up at idle like a carb motor, and the top end should be about the same.

I would recommend moving the ECU's enrichment wire connection (YEL/BLK) from the starter solenoid to the "Push Key to Choke" button, for more reliable starts, and more user control.

-Chad

[Terry Jackson]

Thanks Pyro, I missed the 2.5 part of the post. Yes, the first were the lasers rated at 220 for 87 & 88, then changed to 200 in 89.

[LdyAv8r]

Your right about the engine.....
The boat is 1986 , the engine is a 12/01/91 2.5 laser. I am pretty sure its all original, but it does say 175 xri 2.5 on the cowling.