Merc 2.5 advice

[91nitro]

This is a 1992 Mercury 2.5 245 Hp carb model 20" shaft.
This motor has only about 20 hrs since new and has been sitting inside (heated) for many years. Possibly nine to eleven.
1.Will there be any problems with it for sitting that long?
2.What are the pros and cons of this motor?
3.Someone advised me these motors require rebuilding every 150-200 hours. Is this true?
4.How will top-pinning help?
5.If I got this motor what would I have to do to it before I should run it?
Thanks in advance...really appreciate the help.
Mike

[Raceman]

The carbs will probably need taking off and cleaning, since they've probably got some dried fuel residue in bad places. It'd also be a good idea to replace the waterpump impeller and change the gear oil. Outside of that it should be good to go.

[Fish]

its a good motor. Rebuild will depend somewhat on how hard you run it; rpm's shorten the life. There are better folks to give advice on top pinning and lots of threads about, but basically if the pin works its way out in a side pinned motor, it can get wedged between the piston/ring and the cylinder wall and things ain't good at that point, especially at 8000+ rpms. If given the choice, go with top pin; some folks will only run them. I have side pinned right now, but next tear-down, top pinned are going on my motor.

BTW, welcome to scream and fly!

[91nitro]

Do you think rust would be a concern?

[91nitro]

What is the weight of this motor?

[Capt.Insane-o]

It's a coated bore motor, so little worry of rust on the bores. If it was in a dry heated environment, very little worry of any rust on the crank bearings.


1. With out any doubt at all it will need a water pump impeller and the carbs cleaned.

2. Cons...weak charging system. I always use a 1000 cca battery and had a solar charger I rolled out on the back of my boat when at the beach or where ever. Between the ecu (not in your case)/fuel pump/jack plate and trim. They sometimes have a hard time keeping up.

3. Run like they should be, 100-150 hours is common for a refresh. I had a friend with a 260 on a bass boat and logged 400 some.. drove it like a sissy though.

4. Top Pinning. Cheap cheap insurance. And more so peace of mind.

5. See #1

Weight is 400 ish.