1998 Evinrude Power Head Blown

[MMadatic]

I recently bought a 1998 Evinrude 150 (carburated) engine for use on my Sea Fox center console Model E150EXECD. The engine was blown with the number one piston bad. I replaced that piston, new sleeve, new crank, new main bearings, new head on that side, and all new rings. Engine ran fine during initial breakin and next 5 hours. The engine failed running at 3500 RPM. It did not lock up however started to knock. NO engine warnings prior to failure. I should note here I was still using double oil mix as recommended by the manual.
I have disassembled the engine. Here is what I find. The number 4 cylinder has failed. The lower part of the cylinder sleeve has broken and of course has been broken up by the piston. No parts broken off the piston. It is very dinged up and must be replaced. Piston rod is in tact. No bolts missing. All berings in tact. Rings in place however broken due to the debris. I checked read valves and all is in tact. It appears that the sleeve broke on it own. I cannot find a reason why the sleeve broke....NO lose bolts, no ring peices etc. Any ideas. I dont know if I want to rebuild this engine again without a reason for this failure....

[ChampioNman]

The sleeve may have already been damaged when #1 went and you just didn't happen to notice it. I would make sure that the locater pin in the #4 piston is there also and have the head flat ground at a good machine shop.

[MMadatic]

Just checked. Both locator pins are still in the piston. I checked the rings again. Although cracked, all peices are still in the piston. Also, the head is badly pitted due to metal peices hitting it from the sleeve. I have a spare head from the first rebuild. Recommendation for proceeding?? New piston, New sleeve, Rod??, Rod bearing?? Any special checking on the unaffected cylinders? (I will need to pull all cylinders to have the sleeve put in)

Thanks for the help..