Carb bowl corrosion

ed72vette

Seaman
Joined
Oct 21, 2004
Messages
71
I just opened the cabs on my 90hp 2s 2004 Yamaha outboard. All 3 carbs have corrosion inside the float bowls. Is there a corrosion leveling coating that I can apply and will not be effected by 10% ethanol fuels?
 

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,019
Re: Carb bowl corrosion

No coating. Just fully clean the carbs (I use a carb cleaner dip), keep them clean and don't let the fuel sit in them for extended periods.
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Carb bowl corrosion

That carb float chamber corrosion is caused by small amount of water there...another really good reason to drain each carb float chamber a couple of times per year and especially during motor lay-ups of more than several weeks....
 

ed72vette

Seaman
Joined
Oct 21, 2004
Messages
71
Re: Carb bowl corrosion

Thanks for the info. I have been draining the bowls over the winter for the last 9 years, but I have not been draining them when not being used during periods of non use in the spring and summer. I guess I will have to be more diligent in draining.
 

Fastatv

Petty Officer 1st Class
Joined
Sep 28, 2013
Messages
258
Re: Carb bowl corrosion

Some may disagree with me on this but, when I lived in Florida and rebuilt marine carbs, it was common to find corrosion in the bowls. I gently sand blasted the bowls, and using an acid type brush, applied a thin coat of Marine Tex ( think that was what is was called ) to the inside bottom of the bowls, filling in the areas that porosity was evident, never had one come back. Rick
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Re: Carb bowl corrosion

Thanks for the info. I have been draining the bowls over the winter for the last 9 years, but I have not been draining them when not being used during periods of non use in the spring and summer. I guess I will have to be more diligent in draining.

When you drain float chambers, tilt motor up slightly so the drain hole is a bit lower and drains completely....with drain plug out, pump primer bulb a few times to "flush" chamber a bit to remove any water/contamination. I always put a rag or towel under carbs while draining to catch drain plugs, fuel during the procedure....good luck!
 
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