# Yamaha cowling with oil stains



## Jared D (Mar 17, 2018)

I am not a mechanic at all…. My F40 Yamaha (2020 yr w ~ 80 hrs on it) has some oil stains showing on the port side of the lower unit cowling. (Pics aren’t the best- can take more if needed).
Not sure if this is something normal or something to be concerned with. Want to troubleshoot but not sure what to look for.
There is no oil showing under the main cowling- the head looks really clean.
Should I be concerned or is this normal?


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## Jared D (Mar 17, 2018)

Btw, motor runs great…. No issues at all. Just trying to get in front of an issue if this is problematic.


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## Sublime (Oct 9, 2015)

Where is the oil level on the dipstick? Have you sprayed some kind or corrosion blocker under the cowling and maybe it is running down the engine?


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## Silent Drifter (Apr 29, 2021)

Id either take it to shop, or pull that middle section "cowl "off and have a look! And as mentioned by Sublime check and monitor the oil on stick...

Check around your fuel pump ive read the O Ring sometimes leaks 🤔


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## Frank Ucci (Jan 20, 2019)

Check for a slow drip under your oil filter. It might just need to be tightened 1/4 turn.


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## Jared D (Mar 17, 2018)

Thanks for the replies. 
checked oil- it looks right.
I did put corrosion blocker on a couple years ago…. So run off is a possibility.

I also pulled the lower cowling. I cannot see any leaks, grime, or issues.

Not being cheap… if this is something in your mind that could be problematic… I will take to the shop.
But my dealer is 50 miles away… so time is my issue. 
what would you do if you were me?!?


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## Frank Ucci (Jan 20, 2019)

Put muffs on it and run it with the cowls off and see if anything appears.


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## Capt. Josh Gisclair (Mar 13, 2019)

Have you completed a oil/filter service recently? I also have a 2022 F40. I would check around filter area like Frank Ucci recommended. Also look around lower cowling for any left over oil from an oil filter service. 

On these current style F40's the oil will drain right down that skirt when changing oil filter. Even though you might think you contained it all during the filter change.

When I do a service on my F40 while being as neat and as clean as possible im still wiping up oil where your stains are for a couple trips then all good.


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## Jared D (Mar 17, 2018)

My last ( and second) service/ filter change was last summer. I noticed the staining this summer…. But while pics don’t really show it, the stains appear to originate under the lower cowling.

I will pull it out of the barn and run it w/ o the lower cowling and see if it has any seepage.


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## Sirhc30 (7 mo ago)

Have you tried cleaning that stain off? If not I would do so and check it again. Looking at the location of the stain, I'm of the belief it was something you sprayed on the motor. It's impossible for the oil to pool there while running and you would have seen the oil below the engine when stored.


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## Jared D (Mar 17, 2018)

I have tried scrubbing the stains off- but just using soap and water.
I am open to anything that may be better to remove it. I normally would not care about a stain on the motor but want to be able to see if this is an issue or just something that happened once and is not an issue.


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## Frank Ucci (Jan 20, 2019)

WD-40 will clean off the stain if it is an oil based stain.


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## Silent Drifter (Apr 29, 2021)

Try tooth paste on a small area.a "lil" on a rag rub it with finger in rag , i thought i ruin my lights on my cat 988 i was spraying the guards infront of lights got black over spray on lights,thought to myself no problem, got a can of brake cleaner it took the overspray right off ,but made the light look milky.i had toothpaste in my back pack in break room got a lil on a paper towel rubbed the lens it looked new in no time! I used the Colgate paste white in color ,not the gel stuff

If that dont work get more aggressive go buy a 10$ bottle of scratch doctor......just about everyone carries it ....its in a orange with black top tube


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