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White smoke out prop!

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Ups151

New member
Is just rebuilt a merc 305, this was my project boat for three years. I have check the plugs and they are perfect, compression is spot on, oil is a super clean no milky color what so ever, I saw a few posts about a bucket test I am not really sure what that is or if someone could reach out and give me some advice on where I should look next I would be in your debt, or I'd buy the frist round or two! This has been an epic battle between this Wellcraft and I, from stringers to the kitchen sink it is now a matter of will I just hope this white smoke is not the death blow. I haven't even left the garage with it yet, any direction would help.

Thanks for reading

Derek
 
he means besides yours... do you have a frame of reference for what normal is?
(same question my therapist asked me lol)
 
hystat said:
he means besides yours... do you have a frame of reference for what normal is?
(same question my therapist asked me lol)
Click to expand...
Same here..... my therapist asked my the same question, and more than once! :D


Derek, can you give us a bit more info?
Is this engine fitted with a Closed Cooling system, or is it Raw Water cooled?

White smoke may actually be steam gasses.
Water when warmed up in the exhuast system can turn into white steam.

The task is to find out what's causing this.... or to learn if there is an actual problem at all.

Could be:
  • unequal exhaust cooling water. i.e., one side getting warm enough to turn it into steam.
  • not enough cooling water.
  • cracked manifold allowing water to enter directly into the exhaust flow.
  • head gasket failure.



You'll want to do a P of E.... process of elimination..... one item, and one item only at a time.


.
 
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Doin't be shy with the water to the muffs during test running!
You should open the tap wide open, and there should be enough water flow such that excess sprays out the sides of your muffs.
The white smoke you see may be steam if you have insufficient water flow, and that ain't good.

Rod
 
What year is your Wellcraft?
I had a '77 tri-hull back quite a few years, with the model 898 305 2 bbl and pre-Alpha drive.

Rod
 
I wanted to say thank you to everyone that replied, I found three inches of rust under the thermostat, my heart was pounding when I saw that smoke pouring from the exhaust. Rick I want to personally thank you your knowledge and advice, one step at a time and one problem at a time. Thank you very much.

Derek
 
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