running a thru hull - that avoids that potential problem...good move !

this is gonna sound really strange: just work with me...

flushing - sounds like a really good idea,right ?

in just about 20yrs,in this biz - i've never seen an engine failure,directly caused by an engine being raw water cooled.i've never seen a "clogged cooling jacket",never seen a block rusted through...

if the engine's filled with water - even sea water - there's an absense of air - no oxygen,right ?


the weak link on gas engines is the exhaust system - be it either stern drive,or inboard - these are the most common cause of an engine failure - some engine mfg's do not include the mainfolds in their fresh water cooling systems - some do - crusader,is a mfg that does...with all that,the risers,or,the manifolds are expelling sea water - meaning,these have a finite life.the normal accepted life is approx 5 years.flushing with fresh water will not prolong this - against popular belief...

it seems we're on this subject,so - i'm gonna run with this...

see next entry,for more info...

center consoles - seacraft center consoles - they've got a flush fwd deck - this is where you battle a big fish from - the engine box isn't a factor - you fight the fish from the bow - fish "pulls" the boat,plus,whoever's on the helm,you can see what's going on,to follow the fish - the boat handles a little easier from the "pointy" end...

this is how it's done...

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...

Don't have one. Typically they never last long anyway when repleced.

Yep ! That'sa right :D

nice capt !!!

Pelican-
I suggested the flusher for the bravo because my boat has the same cooling setup and with the boAt on a trailer i now have a good system to run it in the driveway.
I agree about the block flushing not accomplishing much.
I've been down the manifold failure route-aint no fun. Was able to save the motor though with some quick action.

My 350 Mag MPI has closed cooling (including the manifolds) and came from the factory with a quick disconnect for running it on the hose.

Pelican
What is the most common cause of water ingestion, manifold failure? Do the manifolds rust out from the water jacket side, or from the exhaust passage side? Or is it riser gasket failure?

Dave

i think you might wanna check that cooling system again - i don't think merc manifolds are freshwater cooled.

the cooling passages will erode - the gasket surfaces erode too - mercs are not as prone to this,later model mercs - they use a "dry joint" system...

those MPI'S with the horizon package - like the one you have,is it new as in 2011 ? if so,it would be equipped with catalytic converters - to pass the emissions standard ...your engine cat equipped ?