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Discussion Starter · #1 · (Edited)
ok, i got my boat out and it runs fine. But it is smoking. it doesnt smell like its oil related, it looks and smells like exhaust does when its a cold day.....you can see your exhaust. anyone have any clue what would cause this? i have check the pressure on all cylinders, all are good. oil was just changed and looks great, not milky at all. everything is tight. boat runs fine just when i get on it, it smokes. when i let off the throttle, it will smoke for about a minute then stops. doesnt smoke at all during idle. im lost any ideas? its a 1985 mercruiser 260. 5.7 thanks.


Think it might be water in the fuel? moister in the exhaust?
 

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Mine does that by choice - I run my exhaust almost dry
so I get alot of steam.
It might just be steam. could be you need a new impellar in the water pump. could be that you have a blocked water passage causing the exhaust to run hotter than normal.
 

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Discussion Starter · #4 ·
im pretty sure its the original exhaust. thats what i was thinking...steam. how would i remedy this? new exhaust? i will put a new impellar in it before i take it out again. see if that fixes it.
 

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Discussion Starter · #5 ·
WHAT NOW!!!!
put a new impeller in it, and it still steams... how would i check to see if the exhaust was blocked? Thanks. also how much would replacement manifolds be?
 

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Discussion Starter · #7 ·
not for sure the exact amount but a pretty good bit. is just as much as last year when it wasnt steaming. it stays cool. like i said everything runs fine. the right side seems to have less water coming out, but both sides steam. any ideas?
 

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If those are the original manifolds I would think about changing them. How do your plugs look? If they are super clean you may be getting some reversion. I had some intake valves ruined by bad manifolds on my Scarab 1. If you run in fresh water get some aluminum ones. Those old iron manifolds weigh a lot. Mine does not steam much unless the water is cold.
 

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Discussion Starter · #10 ·
any particular brand that you recommend? Im not looking for performance. i just want to enjoy the boat and not have to worry about anything. is there a what to take the old ones off and have them cleaned out? or just trash them and get a new pair? Just looking for the easiest way to get it fixed.
 

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Trash them. If your looking for a good replacement be it cast or aluminum, Sierras and Osco's are good. For aluminum ones the GLM are good.
 
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