Boat exhaust smells very gassy - kinda like me :)

[Rupp]

Guys,
When I'm reversing my boat I smell the exhaust and it smells very gassy. The boat runs very well but from time to time if I stop on the lake and do not let it ldle for a few secs it's hard to start and appears to be flooded. Any ideas on what causes an engine smell like this? Is it running to rich?

 

[Don S]

Re: Boat exhaust smells very gassy - kinda like me

It happens with carbed engines. Let it idle and cool down to burn some of the excess fuel it gains from bringing the throttle back to idle really quick.

 

[Rupp]

Re: Boat exhaust smells very gassy - kinda like me

So the "gassy" smell is normal when going in reverse?

 

[Augoose]

Re: Boat exhaust smells very gassy - kinda like me

So the "gassy" smell is normal when going in reverse?

Like Don said, with carb'd engines its easy for there to be unused fuel from all of a sudden going from open throttle to a stop or backing up, and yes you can smell fuel on occasion. When you back up, the wind is carrying the fuel vapors to you so you notice it. Or, you may notice it if you are swimming to the back of the boat after skiing as well. Fuel smell all the time or just while its idling is a problem IMO.

If you are running rich, there are several things which can cause a fuel smell. Start with this- pull a spark plug, take a photo of it and then post it online so we can see how it looks. Dark soot can indicate rich conditions which light or whitish powder can indicate too lean conditions.

Doing a tune-up on carburetor seems daunting buts its really fairly easy if it comes to that. There is a wealth of info on line for the holley carbs the 5.0 runs.

 

[Don S]

Re: Boat exhaust smells very gassy - kinda like me

So the "gassy" smell is normal when going in reverse?

If, the choke is on or it's running rich and you put it in reverse and back up under the fumes, then yeah, it's a normal smell.

 

[Rupp]

Re: Boat exhaust smells very gassy - kinda like me

Hum.. This has me wondering. Don't get me wrong the boat starts withing two cranks most of the time but the choke comment brings up a new question. In most applications when an engine is choked it idles at a bit higher rpm's until it's warmed up. My boat has never done this. Should it? Maybe I'm having a choke issue.

 

[Don S]

Re: Boat exhaust smells very gassy - kinda like me

Hum.. This has me wondering. Don't get me wrong the boat starts withing two cranks most of the time but the choke comment brings up a new question. In most applications when an engine is choked it idles at a bit higher rpm's until it's warmed up. My boat has never done this. Should it? Maybe I'm having a choke issue.

No, most AUTOMOTIVE carbs do that, not marine carbs.

Marine carbs do not have high idle stepped cams like automotive. You have to use the throttle lever in the neutral only position and put it where you want it for rpm.