Exaust / gas smell?

[vjvillena 2]

 

 

I have had this random smell of exhaust or gas in the bilge at random times throughout the day and I cannot figure out where or why. It has always been like this since I purchased the boat in 2010.

 

I was wondering if anyone has had this issue. It's driving me NUTS!

 

Here's when I notice the smell:

 

1.) generally the bilge area has what my mechanic likes to call a "boat smell" which is basically a oily, metal, engine and fiberglass like smell".

 

2.) when coming to a stop from surfing or when I come to a stop the combination of the "boat smell" and gas and/or exhaust smell seeps through into the cabin area. Not extremely strong, but enough to wonder. I run the blower and it seems to go away.

 

3.) the smells location is completely random. Sometimes in closer port, other times it's on the starboard side. Other times it's closer to the ski lockers.

 

 

What I have done:

 

1.)My mechanic checked all fill lines and vents, looked for cracks in tank, fuel filter and also the fuel sending unit. Everything was intact.

 

2.) no visible gas in bilge water.

 

3.) cleaned the bilge.

 

My conclusion:

 

1.) I think it might be what they call the "station wagon effect" where the exhaust travels back into the cabin area and vents.

 

2.) my tank was filled too much causing more fumes to vent. In comparison, when the tank was closer to empty, the smell was less apparent.

 

3.) since the tank is plastic it is permeable and hence smelling the fumes. When all the heat from the engine is trapped while not moving, the smell of gas combined with "boat smell" is rising through all the areas where air can flow.

 

Again, I run the blower all the time and especially when I start to smell even a hint.

 

Have you or any of the mechanics there run into this????

 

My boat is a 2007 centurion enzo sv230 with Sideswipe.

 

Thanks

VJ

[WickedC4 12]

Maybe a exhaust manifold leak? When you start it up listen real good to each side. Ticking. . . .

[jiriki 13]

I hear ticking on mine...

 

I assumed it's a sticky valve..

[vjvillena 2]

I was thinking it may be exhaust related. I will listen for a ticking sounds next time I am out. I assume the ticking will be around the exhaust?

[BillC4 24]

Great thought on the exhaust manifold.

 

I put the fresh air exhaust on my boat last year and all that smell is gone. Now, when I ride in other boats I really notice the exhaust. Best mod I've done so far.

[enzo on LI 79]

I was thinking it may be exhaust related. I will listen for a ticking sounds next time I am out. I assume the ticking will be around the exhaust?

Correct. If you hear the ticking replace the exhaust manifold gaskets. Easy and cheap!!!

And will hopefully eliminate smell.

Edited June 26, 2014 by enzo on LI

[WickedC4 12]

Leaking off to the left port. easy to change out but need to people. Oh and don't drop it on the spark plugs...

[WickedC4 12]

Bill your right about the FAE.

[NW Boat Sports 232]

OP, I assume your engine does not have Cat converters? We mostly drive and work on boats with cats, but recently we have had a few in the shop that don't have them and I have noticed the gas smell you talk of. Could just be unburned gas making it's way back into the cabin from the transom of the boat. My two cents. Good luck

[vjvillena 2]

I don't believe my boat has a cat converter... I thought it might be unburnt gas as well because I usually smell it within 5 minute after throttling down from surfing or cruising.

Thanks for everyone's help. I'm going to check the exhaust manifold asap and keep you posted.

[vjvillena 2]

Leaking off to the left port. easy to change out but need to people. Oh and don't drop it on the spark plugs...

WickedC4-

Thanks for the pic!

 

What other symptoms would occur if the exhaust manifold gasket needs replacing beside "tick tick tick?" Would the performance be effected? I have not noticed any performance problems at all.

Thanks!

[WickedC4 12]

vjvillena, no problem. no performance loss if your system does NOT have CATS. And even if it did the loss would be to little to even fill.

 

take a pic. of the motor and post it.

[vjvillena 2]

Maybe a exhaust manifold leak? When you start it up listen real good to each side. Ticking. . . .

i finally was able to take the boat out last weekend. Had 2 mechanics with me at the time. NO TICKING! NO EXHAUST LEAK!

 

W

[vjvillena 2]

The mechanics and i again smelled the exhaust-gas smell at rest after the boat had been running for 30min or so. It was also really hot outside at the time - 100 degrees..... Keep in mind, it did not smell before this. They all came to the conclusion that it could be diurnal emissions:

 

http://www.boatingmag.com/how-to/fuel-system-safety-tips

 

The smell only occurs when the engine has been running for awhile, and at the same time the weathers temperature increases....

 

Thoughts?