Mercury 25-XS

[Guest]

I have spun the flywheel so often on this engine that it is time to replace the crank and flywheel. I have the crankcase split and wondering what size wrench fits the rod screws. It appears to be 1/4 12 point screws but I am not sure. Tried a 7mm but that appears a little to loose on the head. Have the new crank and flywheel ready to go in but don't want to mess the rods up in that the screws are NLA from Mercury.

Thanks for your help,
Alan

[ZUL8TR]

question

Alan have you determined why the flywheel keeps spinning off? The new flywheel and crank might go thru the same failure? Does your 25xs have the earlier heavy flywheel? Will you be balancing the new flywheel?

Don't know on the size for the con rod bolt.

[Guest]

25XS flywheel.

I think the issue started before I acquired the engine. I have lapped the flywheel to the crank with little luck so I decided to change the crank and flywheel and start over. I can do a static balance on the crank/flywheel. The engine has the standard flywheel and not the light one. I believe the rod bolts take a 12 point 7mm socket which I will have to buy. Lots of 6 point tools.

Alan

[Guest]

Crank Changed.

The rod fasteners turned out to be 1/4" 12 point so it was quite easy. There are only 30 total fasteners to remove and replace to change the crank. Quite an easy job which took less then 3 hours.

Alan

[Guest]

25 XS is finished

We decided to fire the 25 XS after the crank and flywheel change and all is well. Now we will have to try it on out C boat at the NBRA race next weekend. Anyone have an idea on what we can expect speed wise?

Alan

[Fast Jack]

rod bolts

I Just got 2 bags of 25 mercury rod bolts -They were available- in stock at Seaway !!