ligtly rebuild 235 engine?

hi i was thinking i bought my boat about a month ago with that engine and it got overheated and started opening it checking what could have broken and disasembled lower unit and all , should i change the piston rings, gaskets beside changing water pump, impeller, sparks,wires , broken head bolt so that i dont have to worry when i asemble it back that something that i did not change could now break example power head gaskets piston rings ect?

Re: ligtly rebuild 235 engine?

Probably the first thing to do is find out why you did not get a hot horn in the control box-and fix that problem. No mention was made of any damage from the overheat...cylinder walls,pistons or head face damage. If you literally have it all apart, it is an opportune time for at least new rings and honing of the cylinders. In addition to the parts you mentioned, a new powerhead gasket kit and three carb kits will be necessary. I would also tear down the thermostat housings, replace the thermostats and check the nylon pressure relief valves-replace if warped. On overhauls, we always replace the VRO pump too, but it sounds like this was not the root cause of the failure and it's replacement would be your option.

Re: ligtly rebuild 235 engine?

those 235 engines are a son of a b.they are over bored to points that the cyl. walls have little left.that causes many problems,one,the ports crack easy when overheated,or pushed hard,the alum up by the top of the cyl,where the head gasket seats often corrodes to a point that just the steel sleeve makes the seal with the head gasket,allowing failure easy,you say you have a broken headbolt,that needs to be fixed,but I got to think you may have an eng.run in salt water,if so,be certain to look this engine over real well.
if you have it apart,with pistons out.look with a flashlith ate the port holes in the cyl.notice if you see line cracks between,if you see any,that sleeve needs to be changed,you wont get away with just honiing that block and sticking new rings on the old pistons,the cylinders need to be round with a boring,the exhust plates on the eng,should be resurfaced guareeting an even seal to keep water out,once taken apart,you need to do this.there is no lightly rebuilding those large bore crossflows,you will suffer constant problems