Merc 250 xs mods/upgrades/general maint.

[WHISKEY-7]

Hey guys I'm new to the site so thanks for hosting this place so we can all share info. I just picked up a pair of 250XS optis from 2003 with about 1400 hrs on them. They were on a fishing boat so most of the hours are from idling while drifting. They are super clean corrosion wise and they run good but they still needed some care so I decided to do some upgrades to keep them going. Just got done putting on a pair of new compressors, and 2 new alternators b/c they were both not charging. I also upgraded the wire that ran from the alternator to the starter solenoid with the inline 100 amp fuse. I changed a few oil lines that were in rough shape and all the little filters. Also took the compressor water strainer out and cleaned that all up as well. They had the torque master lowers recently rebuilt and they are perfect right now which is nice. I took the boat for a spin the other day and after I borrowed some props (rev4 19P's) I was able to get 54mph and 5600+ rpms with a full load of 250 gallons fuel and 100 gallons of full live wells. The boat is a 31 contender so not light and not a racing boat when she weighs in around 11K fully loaded. Light with about 100 gallons of fuel she will bounce on the rev limiters around 5800ish while trimmed up but she is only hitting 56 with that load. The plan is to take the motors off and find an older project cat hull from 27-33 ft to set up for some fun and repower the contender later on.

Next up for the engines is to get the fuel and air injectors out and send them to Brucatos to get flow tested just to be on the safe side and then get some new plugs installed. Im also gonna check the reeds this weekend while I have some spare time. Then maybe while the injectors are out I might pull off the heads and change the o rings just so I can get a good look at the pistons and combustion chambers.

I joined the site b/c there seems to be a lot of guys running opti xs motors and I figured I may be able to help where I can and also get some help where I need it as well.

Here are a few things I'm looking for...

Where can I acquire some of the billet compressor pulleys that some optis come with? Im guessing these started being used on some of the later model xs motors but I really am not sure. I'd like to get them if I can so if anyone can point me in the right direction I'd appreciate it.

Also is the lightened flywheel a common upgrade that guys do or is it even worth doing?

What else are you guys doing to these older optis to get em spruced up???

[WHISKEY-7]

Oh ya, also did new oil tanks b/c the magnets were bad in the old ones and kept setting of the 2 min beeping alarm. I bypassed the sensor for a few runs then decided to just put new tanks on. Im pretty good about keeping an eye on the oil level but Id rather be safe than sorry. These optis have run DFI red oil for the last 1000 hrs b/c the owner fished a lot and did a lot of idling. I was debating switching back to premium plus but not sure if I'll do it or not. Maybe when I swap the motors to a cat hull and I start keeping the engines in the upper end of the rpm range for more than a few minutes I might make the switch. Right now I haven't really been doing that yet so Im not in a rush to swap.

[2jz]

Welcome to S&F
Billet pulley by mercury 843224........new # mercury 8m0051194. You can find them little cheaper priced using old part#
I have lightened flywheel if your interested pm me

[WHISKEY-7]

Hey thanks for the part numbers man! Is it necessary to order the longer bolts for the billet pulleys? The standard bolt says m6x12 and I'm sure that the pulleys on my 250xs are the same as the old 225 optis that I used to run b/c I did the compressors on the old 225s as well and I saw no difference. The pulleys are identical.

I'm guessing I will need to order the longer m6x20 bolts for the billet compressor pulley since there is a washer that fits on top but just wanted to double check before I put the order in. Do you know if the billet pulley comes in that blue anodized color or dis merc tone that down?

PM sent on the lightened flywheel.

[2jz]

It's best to buy washer ring and bolts. Washer ring is to protect aluminum pulley form bolts wearing groove in it from tightening down bolts. Yes it's blue anodized color

[WHISKEY-7]

Gotcha Im gonna order them as well. Hopefully the billet pulley will help reduce some of the stress on the upper bearing of the compressor as well as help with cooling since aluminum disperses heat well. I have the new style compressors which are supposedly upgraded internally and are said to be much better than the previous design which some people got 1000's of hours out of and others never got 1 trip out of them.