Things to do after engine sucked in water

saf

Petty Officer 3rd Class
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Nov 22, 2019
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Can somebody point me to a list of recommended procedures after water intrusion into the engine cylinders?
So, I had a slight cylinder head overheat due to brief water flow restriction to risers during cooling system testing. Nothing substantial, engine temperature gauge barely moved above 160. Was enough though for dieseling to start (note to self, those ACDeloco are crap, never had that with Champion plugs I had before). Long story short, the engine spun in reverse and sucked in salt water. Tried cranking it - no turning. Immediately realized what happened, took the spark plugs out (water came out), cranked the engine without plugs to push the remainder of the water out, reinstalled plugs, started the engine (took some cranking), the engine seems to be OK. Took the bout out for a spin, everything seems normal. Engine oil looks clear. I will do the oil change ASAP (obviously), anything else I should do?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Dieseling comes from the timing being off, not brand of plugs. Verify your timing
 

Augoose

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Scott is right on....
as for the water intrusion when it happened to me recently I pulled each plug, turned the engine over like you did to exhaust water, then sprayed WD-40 inside each cylinder as my engine was going to sit a bit. Running yours should have taken care of any moisture in the cylinders.
Going forward, check the oil level on the dipstick and see how much water you took on by seeing how much higher the oil level is. Mine was significantly higher. Change the oil and filter asap. I flushed my engine twice using cheaper oil and running it a bit on muffs between flush cycles.
 

Lou C

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Also; the dieseling is not due to engine temp per se which in your case was not excessive. Excessively lean fuel mix can be a likely cause as can carbon deposits from running too cold (no thermostat, defective thermostat). In fact I recall there was a service bulletin from Merc on dieseling and what to do about it. What did your plugs (center electrode insulator) look like? Blistered white suggests that the fuel mix is too lean, tan/brown or grey is good. This may be peculiar to the carb Merc used and how it was jetted/set up because I have the same engine but with a Quadrajet and it’s never dieseled in the 18 years I’ve had it.
 

Lou C

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PS nothing wrong with AC Delco Marine plugs in fact they are preferred to Champion. If need be you might be able to go to a cooler heat range.
 

saf

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Nov 22, 2019
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Thanks, guys. Will do the oil change ASAP. The reason for the question was an old conversation with a VP mechanic who mentioned that Volvo recommends flushing the engine with something to prevent salt deposits on valves (I might have misunderstood what he was saying though). Do you know anything about this?

On dieseling issue: perhaps I used a wrong term. I was talking about the situation when engine continued firing after ignition was off. Not sure I see how timing would play any role in this (with ignition being off). Lou, I think you are right, I did notice several plugs were bright white. Several others were nice golden brown color though. Vacuum leak? I looked for it multiple times using the "carb cleaner spray" technique - could not find anything. Do you have any other suggestions on how to find the leak? Maybe it's something else entirely?

My ACDelco spark plug frustration is based on this: I've replaced Champlions with a new ACDelco set to look for color diagnostic (been struggling to tune my Edelbrock for a while now) and this is where I started having the dieseling issue. ACDelco model cross-referenced to Campions, nothing else has changed, hence, I was inclined to blame ACDelco plugs. Perhaps the cross-referencing sheet was off, found it online...
 
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