Smell gas in oil?

BoatNoobie

Petty Officer 1st Class
Joined
Jun 17, 2009
Messages
314
I started my winterizing process today. It is a 2005 Mercury 60 ELPT 4-stroke. Picked up the used boat combo this June.

Ran it all summer with zero issues. Starts right up and purrs like a kitten. Feels like full power at WOT. My top speed is comparable to others with similiar setup.

Out on the water, never noticed anything out of the ordinary.

So today, I changed my lower unit fluids, oil/filter, and spark plugs. There was obvious water mixed in with the lower unit. Glad I changed it now otherwise I know I'll have issues when it starts to freeze up here(WA).

Then I changed the oil. I didnt smell any gas as it was flowing out. But when I wiped up the mess on the outboard, that's when I was able to smell it. So it's not a strong smell, but pretty sure it smells like gas. Or maybe something like gas? :confused:


When I changed out the oil in my Merc 15 4-stroke earlier this year, I dont remember it having any smell to it.

So is something wrong with my new motor?
 

BaileysBoat

Senior Chief Petty Officer
Joined
Sep 29, 2008
Messages
716
Re: Smell gas in oil?

Has the oil level been going up? A million posts about making oil. Probably all is well.
 

Bob's Garage

Chief Petty Officer
Joined
Apr 10, 2008
Messages
590
Re: Smell gas in oil?

Sounds like 2 issues that will need your attention this winter; Water in lower unit, and fuel in crankcase oil.

Neither should be ignored but you have all winter to fix them. Sorry I cannot give you any help on the gas, but the lower unit could be;


  • Fishing line cut prop shaft seal.
  • Oil or drain plug gasket
  • Internal seals on drive shafts

There may, of course, be other causes, but these immediately came to mind.

Enjoy your winter.
 

BoatNoobie

Petty Officer 1st Class
Joined
Jun 17, 2009
Messages
314
Re: Smell gas in oil?

Has the oil level been going up? A million posts about making oil. Probably all is well.

I dont know if the oil level went up or not, i didnt check.:redface:
But after mentioned that, i did a look searching about "making oil".

Earlier in the day, I did take it out to the local lake to give it 1 last run around. But I was too early and had to drive around at low speeds only. No more than 8MPH allowed during the time. Most I was putting around at about 2500 RPM. I was trying to use up as much gas as I could, before I drained it.

I was never able to do any full throttle runs like I usually do.

So I wonder if these is the cause of it. I mean the smell was not very strong. You had to get it all the way up to your nose before you could smell it. Then again, maybe I just suck at smelling things. :(





And about the lower unit, I'm HOPING it's just the drain plug gaskets. There's 3 of them, so more room for error. And it's the easiest fix that I can do myself.

The other 2, I have no idea how to tackle that, so a shop will most likely do the work and that'll be $$$$$. :(

Will find out next spring.
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: Smell gas in oil?

Mainly gas can get in the oil by 2 ways;

By the rings, mostly when the engine is in the warm up stage, before the rings expand all the way, or if they are worn.

Through the valve guides if they are worn.

Keep an eye on your oil level next spring. If it was as you say not very noticeable it may just be from warm up and no big deal. If you have any of your old oil you can send it in to be analyzed and find out just what is going on inside your engine. If not do so next oil change.

Do you pull your prop to grease the shaft when you do a lube service? You should. If you see fishing line there do not just grab it and start pulling or you will cut the prop seal, rather try to pull it off as if it were a sleeve straight off the shaft not around and around. Sometimes this is all it takes and you are good to go.
 

Bob's Garage

Chief Petty Officer
Joined
Apr 10, 2008
Messages
590
Re: Smell gas in oil?

You might ask a shop what it would cost to do a pressure test on your lower unit. Or you could make a pressurizer from a pump sprayer with a gauge. Pump it up to 5 psi and hope it holds.
 

grego

Petty Officer 1st Class
Joined
Dec 12, 2008
Messages
328
Re: Smell gas in oil?

take a small amount of oil , in a small container and see if it flares when lit by fire
 
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