stern drives...

[pelican]

stern drives - gas engines:


the smartest move you can make,is to pull the plugs and perform a compression test,anually.i normally do this at time of winterization.
run the engine,to normal operating temp,and pull the plugs - take a long look at the plugs - you're looking for either "rust stains",or a plug that's "snow white" - this is an indication,that cylinder's burning water - this shows up,way before any water is noted in the oil.mositure rises to the highest point - get in the habit of looking at the "breather hoses",from the valve covers - look for steam - this is another indication,the engine's burning water.a rusted,salt covered interior of the distributor is another - again,all due to moisture rising...
perform a compression test - what you're looking for is "uniformity",each cylinder should be within 10% of each other...

now,if you're compression is low,on a cylinder - odds are,it's caused by,that cylinder ingesting sea water,via the exhaust valve - end result a runsted valve,that has lost it's concentricity - it's not seating properly - this can be verified by a "leak down" test,with compressed air...

get in the habit of doing this,like i stated,anually

exhaust systems are the weak link...

take a look at these pictures - this is a 5.7 merc engine,it suffered an early death,due to it's exhaust system - normally,these engines,when they hydro lock - the small high torque starter,it will break the block - right where it mounts - this one,it didn't,it bent 2 rods - engine was replaced with a new 5.7 mpi merc magnum...at my shop - we do not use "remans",long blocks,short blocks,or offer rebuilds of gas engine,like these - it's repalced with new,complete,drop in engines,or the job's not done...

as you can see in the pictures,some one,used a silicone sealer on the riser gaskets - bad move - very bad...