I have a 90HP 1996 Johnson V4. The bottom most piston is severly damaged as well as the cylinder wall. The cause appears to be water (salt water) entering either from the head gasket or maybe a crack. <br /><br />I have just finished pulling it all apart to inspect the damage and I need to figure out if I can get the cylinder re-sleeved (because it was just a leaky gasket) or get a new block because this one has a hole in it.<br /><br />Any help would be greatly appreciated, thanks!<br /><br />Is there a way to test for a crack /hole in the block? If it were a leaky gasket would I not have had a gradual power loss as well as white exhaust for a bit instead it going rather suddenly?<br /><br />Here is more detailed info on what I found:<br /><br />The bottom lobe of the crankshaft was very rusty and so were the cylinder walls and top of the bottom most piston. The connecting rod bearings broke (most likely due to corrosion) and there were bits of metal from these in the crankcase, intake manifold and in the cylinder. The wrist pin was also seized. The other three cylinders all look good but they all had a tiny bit of what looked like white salt crytals begining to form on the top of the pistons.<br /><br />When the motor seized I had been cruising around for about 10 minutes (but had been using most of day earlier as well as the day before) when then motor started knocking/rattling very loudly. I then stopped the boat but kept it running so I could try to find out where the noise was coming from. It ran for about 2-3 minutes more very roughly then seized completely.<br /><br />5 months ago I had some a problem with my gearcase and had the powerhead inspected while it was in the shop. The compression was nearly identical on all four cylinders and the VRO pump was good.
