cinnr

Sooty transom

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Our J/109 develops a sooty transom from diesel exhaust super quickly.  It's a pain to keep clean and looks terrible if not washed off.

Anyone have advice on how to avoid or minimize this?

I can't believe I'm the only one with this problem...

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One common cause of excess sooting in marine environments is engine overload.  Boat builders specify props that allow the boat to produce the best speed possible when new and lightly loaded, and the engine manufacturer will ensure that configuration doesn’t overload the engine. But, as boats get older, more equipment is brought on board and boats typically get heavier. 

snip

Check to see if you are over-propped.  It’s surprisingly common and, if you are, reducing pitch is easy and cheap, will reduce or eliminate transom soot, and your engines will have a much better chance to living a long and healthy life. It’s nice not having to clean the transom at each stop and potential longer engine life is an additional benefit that is hard not to like.

http://mvdirona.com/2008/04/transom-diesel-soot/

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3 hours ago, cinnr said:

Our J/109 develops a sooty transom from diesel exhaust super quickly.  It's a pain to keep clean and looks terrible if not washed off.

Anyone have advice on how to avoid or minimize this?

I can't believe I'm the only one with this problem...

Probably means your diesel needs a tune up. 

Concerning the soot stain...gelcoat or paint gets sunburnt and becomes porous.  Rubbing compound and polish is about the only way to restore it... 

when sea water evaporates from you hull it deposites minerals ...this calc film  picks up  dirt fast...give your hull a washdown with acid to  cut the calc off. 

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I only had that problem when the mixing elbow on the Yanmar engine had become constricted, which kept the engine from burning all the fuel and led to a loss of power and very dirty exhaust fumes. And a sooty transom. As soon as I replaced the mixing elbow the power came back, the dirty exhaust went away, and the transom never looked sooty again.

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13 hours ago, cinnr said:

Our J/109 develops a sooty transom from diesel exhaust super quickly.  It's a pain to keep clean and looks terrible if not washed off.

Anyone have advice on how to avoid or minimize this?

I can't believe I'm the only one with this problem...

I had a similar problem with my J/109 hull 266 with a Yanmar 3YM30 and ultimately total inability to get RPMs up.  It was a restricted exhaust elbow.  There is a good post on the J/109 forum on how to replace it.  What J/109 hull number do you have and which engine type?

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Probably a tuneup issue but if you have a four position Perko (All Off, 1, All On, 2) make sure that you aren't charging both batteries at the same time.  The load will make the engine lug and over-stress it, generating smoke.  On some of the Yanmar GM3's, a super-heavy constant load also shreds the belt (identifiable by the black rubbery "flour" all over the inside of your engine compartment).   

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Even the newest J/109's are approaching 12 years old now, so restricted mixing elbow (which Yanmars are know for)/diesel tune up are likely due/overdue if not done yet.  Then as Slug says, if hull is still gelcoat, a good compounding/polish with a couple coats of wax will make it easier to clean/keep clean.  

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Thanks all - I will look into these suggestions.  Sounds like we are overloading her (I'm seeing belt dust as well).  And I'll look into the mixing elbow too.

FWIW, hull #106, with Yanmar 3GM30.

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Good luck on the soot fix - sounds like it is the exhaust elbow.  Use the stainless steel replacement available from HDI Marine.  I have a Balmar 110 amp alternator and it wasn't an overloading problem.  I also had the belt dust problem even at idle and it turns out it was due to a misalignment on the alternator pulley.  Check it with a straight edge against the face of the crank pulley extended to the other pulley's.  The alternator pulley was too far aft and needed to have a spacer behind it.   I ultimately got the Balmar  serpentine belt upgrade kit and it actually made the engine run smoother because the belt was slipping.  Read more about it on the J/109 forum at this link.

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our 109 had a pretty clean transom in my memory, even after long hours of motoring. 

That said, a bit of wax on the transom will always make it easier to clean any dirt off. I know some people don't like to wax the hull because they think its slower, or it's too much effort, etc, but the bit of transom is pretty easy to keep a fresh coat of wax on and won't impede speed at all. 

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6 hours ago, mustang__1 said:

our 109 had a pretty clean transom in my memory, even after long hours of motoring. 

That said, a bit of wax on the transom will always make it easier to clean any dirt off. I know some people don't like to wax the hull because they think its slower, or it's too much effort, etc, but the bit of transom is pretty easy to keep a fresh coat of wax on and won't impede speed at all. 

It will if you're trying to back up very quickly!

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Our local USCG large patrol craft took care of this exhaust staining problem on their white LPU paint job by painting the area around the exhaust port black!  

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Products like Permanon are used  on the boot top and exhaust area on big motoryachts 

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On 3/22/2018 at 6:57 AM, proOC said:

toilet bowl cleaner

aggressive cleaners will etch the surface, leading to them getting dirty faster and being harder to clean. Toilet bowl's are a harder surface than gelcoat. 

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Don't let it sit for more than 5 mins.

We have a new marine wax/cleaner that did a great job on 24 yr old fiberglass.  Forgot the name but will find it...

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On 6/25/2018 at 10:48 AM, proOC said:

Don't let it sit for more than 5 mins.

We have a new marine wax/cleaner that did a great job on 24 yr old fiberglass.  Forgot the name but will find it...

Our family has made soaps/cleaners/polishes/waxes since '48, and the collective wisdom is don't use anything more aggressive than you have to. Your boat, your call. 

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