4.3L white smoke

[Camsloop]

I bought a 96 stingray 196 I/O 4.3l this past winter time. Guy seemed like he took very well care of the boat. Beginning of this spring we took the boat out twice with no issues at all. 2 weeks ago I replaced the alternator as well as the coil. (alternator was draining power while boat was off, an coil for prev. maint. ) I started the boat up today in hopes of going out on the lake tomorrow, and it started fine. After the temp. rises to normal temp I get white smoke coming out of the exhaust, and as the engine got warmer the smoke got more excessive.Let engine run for 20 min an cut it off. I haven't ever seen a bit of smoke before even when the boat had been out at the beginning of the season.

Head gasket, cracked block, Intake crack? Any info, suggestions, or help would be appreciated! thanks , cam

 

[alldodge]

Re: 4.3L white smoke

I bought a 96 stingray 196 I/O 4.3l this past winter time. Guy seemed like he took very well care of the boat. Beginning of this spring we took the boat out twice with no issues at all. 2 weeks ago I replaced the alternator as well as the coil. (alternator was draining power while boat was off, an coil for prev. maint. ) I started the boat up today in hopes of going out on the lake tomorrow, and it started fine. After the temp. rises to normal temp I get white smoke coming out of the exhaust, and as the engine got warmer the smoke got more excessive.Let engine run for 20 min an cut it off. I haven't ever seen a bit of smoke before even when the boat had been out at the beginning of the season.

Head gasket, cracked block, Intake crack? Any info, suggestions, or help would be appreciated! thanks , cam

An alternator shouldn't be draining power unless it shorts out.

The engine: Did anything smell hot? I take it the white smoke was coming out the prop, if not where? Does the engine sound normal while running?

 

[redone76]

Re: 4.3L white smoke

stupid question but did you have muffs on and water running in the engine for the entire 20 minutes? if not....ouch

 

[RogersJetboat454]

Re: 4.3L white smoke

As asked, I assume the engine had water through muffs or some other means.

How far up on the gauge did the temp climb?
Have you checked the engine oil lately, and noted if it's gone up or gotten milky?

 

[Camsloop]

Re: 4.3L white smoke

The voltage regulator was still pulling very little power after the boat was off, problem was fixed.
As far as the engine I did have water running thru it with muffs, it reached normal operating temp. On guage an did not overheat. The oil is on full mark an is not milky, loooks like it does need to be xhanged though. when the boat is at operating temp it is pushing very little smoke out of the top vent valves as well. Smoke is coming out of prop as well as im guessing where the bellows are where the outdrive connects. Boat doesnt smoke at cold start up

 

[Zraden]

Re: 4.3L white smoke

double post

 

[Zraden]

Re: 4.3L white smoke

Does the smoke smell like gas? If it does, you might be burning rich.
I had the same problem. It wasn't excessive smoking but by sticking your nose to the prop you could
definitely smell gas.

White exhaust = gas ( burning rich ) or coolant/moisture in the combustion chamber
Dark grey exhaust = burning oil in the combustion chamber

If you don't smell gas then moisture is getting in somewhere which could be from a number of places you
already listed in your OP.

Did you winterize your boat or did you have a shop do it?

From my experience, the easiest place to start checking is your exhaust. Pull your manifolds off and
do an acetone leak test. If they pass, then start working you way through the engine. Do a compression test , ect.

The one thing I have noticed is, it doesn't take long for rust trails to start forming if there is any cracks in heads, gaskets
or blocks so if you have to pull the motor apart because you suspect the engine leak, its usually easy to find.

Also, if you have to pull the motor apart, do a dye test as it will also make it easier with a black light to find if you do have to open the motor. You will also find the dye on your dipstick if its leaking in to the crankcase.

 

[Camsloop]

Re: 4.3L white smoke

It does smell like it is running rich. Could the new coil have anything to do with the smoke? kinda has a rough idle as well wgich it never had before. Never had a bit of smoke prior to coil an alt. the boat was already winterized when I got it,

 

[Zraden]

Re: 4.3L white smoke

I cant see a coil causing the engine to run rich. But I also dont know enough about carbs to confirm that.
Im also just learning the complexity's of carbs. Lol.. I have never worked on a carb engine until I bought the boat. I remember my dad saying we need the set the timing on the boat and me having the most confused look on my face.

I also don't know enough about your engine and when Merc switched over to fuel injected models.

What I can tell you is, chances are your boat has been sitting in storage for the last few months over the winter. If fuel stabilizer was not added during winterization, then your gas has turned to a thick tar and is gumming up your carb possibly messing with the float or jets which can cause you to burn rich. Foreign matter could have entered the carb and can cause the same issues.

I would need someone to confirm you are still running a carb on that engine or not and what would be the best way to clean it up/out to correct your issue. Also, It might be a simple correction of idle/fuel screws but again .. would need to know the model carb if your in fact still running one.

I just chose to rebuild my carb and replace my float in an attempt to correct my issue. Also .. my
bowl was overfilling... a lot.