Burning Rubber/Plastic/Electrical Smell

[Gearyg]

While I am out on the water, I keep getting wiffs, kind of like burining rubber/plastic/electrical or when your brakes are working too hard and you get the buring brake smell. I am never able to pin point it as I smell it and then it is gone. I smelled it while on the stern and the bow and even had a friend on the boat that smelled it too.

I have smelled it while near the docks, 12mi out and when I was at Catalina...it's driving me nuts! I Ohm tested most of my wiring and cannot locate a short (if it was a short, I am thinking that my boat would have burned up by now).

Has anyone have any ideas to my annoying nose? Could this smell be coming from the cargo ships or other. Could it be my washdown pump or bait pump going out?

[fridaysoff]

Gearyg,
I hope its not burning PLASTIC!!!! Just kidding. This may sound stupid,but do you have a 4 stroke engine or a two stroke? You will get some odors from a two stroke that you do not get from a 4 stroke.
JD.

[Gearyg]

I hope it is not the plastic also, I saved some pieces from holes that I cut out in the past, I think I am going to burn them to see if the smell is the same.

I have a Yamaha 4-stroke. I was thinking last night, when I did my oil change, the oil is just past the full line on the dip stick, could it be the oil that is burning off.

[cagrove]

Have you tried to isolate what is "on" when you smell it? Is it only when the engine is running? Was the baitwell pump or bilge pump running at the time or just shortly before? Any navagational lights on? Fishfinder? GPS? etc. There are so many things that "it could be" that you need to rule out the things that are not under power at the time you smell it. Your wiring may still show continuity with your Ohm meter even if it had a short or was getting hot, so I wouldn't rule that out yet.

Have you tried to pinpoint the smell ( stronger in the bilge area, under the console, baitwell, etc)?

Just brainstorming here.

My thoughts are that if you smelled it in so many different places on the water that it has to be from your boat. It's definitely something that I wouldn't ignore.

Keep us posted.

[Grubbs Marine]

Sounds like you have too much oil in her. Yamaha is kinda strange. Yamaha four strokes are full of oil when it is half way between the two lines on the dip stick. If you are above the top line then you have way too much oil in it. We have had this problem before and use a file to mark the dip stick on all the Yamaha four strokes we sell or service so the customer will know not to over fill. Hope this helps!

Todd Johnson
Grubbs Marine

[BarryB]

Burning oil smell is somthing that stays with you for life. So, if it doesn't smell like oil, probably is not. Not sure of the smell, find an old car and sniff.

When I was fishing wires from the battery compartment to the center console, I noticed two wires pinched between the engine mount bolt (Murphy's law, had to be the bolt hardest to get to). I loosened the bolt and carefully pulled out the pair. The wire had been flattened and some insulation was cut. Luckly, I had found this before the other wire had lost some insulation and the two shorted together.

I would look for pinched wires or something overloading a circuit. If a wire or fuse is warm, something is wrong.

[MolarBoater]

It's a long shot but do you ever spray silicone spray on the engine/electronics(with engine cover off)?

[Gearyg]

Thanks for the replys everyone. Unfortunately, the smell very "patchy" I only get a wiff every now and then, and then it is gone...that is what is making it really difficult to trace it.

I am going to run the engine on muffs with all the electronics on this weekend in a nill wind condition at home, maybe I might be able to have a longer duration to trace the smell (or at least confirm that the smell exists off the water) I am also going to drain some oil out of my engine to see if that makes a difference.

I did not spray any silicone on the engine parts though, I did change the plugs last week and based on a physical inspection and smelling around, I did not see anything out of the ordinary...on the engine anyway. I even changed the lower unit oil thinking that the lower unit may be buring up...but what do I know anyway.

Wish me luck!

[cagrove]

Please post a follow-up when you get done troubleshooting. Good luck.

[Whitto]

Good Luck Geary,

We had a similar problem with our new 195 DC ... took a while to track down, but the battery isolator was slightly fried. Must have happened during the install. We replaced it and checked all of the electrics too!

Hope this helps you.