Fuel fumes

[skibard]

Newbie here.  I hope I chose the right forum.

I have a 92 Legend with only 180 hours on it.  It is pristine and got tender loving care every year.  It's had fresh fuel with stabil in the fall of every year.  My problem is fuel odors.  When stored in the garage, the fuel odors become overwhelming in the whole garage.  Especially on a hot day.  I suspected evaporation from the carb, but it would do it all winter long - 10 months some years.  Surely the float bowl would have evaporated dry and stopped fuming by then?  I tried putting the cover on the boat with the tank vent and filler cap outside the cover - and the fumes still built up inside the boat, so it is not coming from the tank vent.  There are not visible leaks or traces.

Experienced marine mechanics insisted (without seeing the boat) that it is very likely coming from the fuel hoses because of ethanol.  I am a little skeptical of that explanation  The hose looks great, is flexible, and has 1/4 in thick walls!  Anyway, I got some high quality hose and started trying to replace it.   Ugh.  The hose is clamped with screws into the hull in multiple places behind the exhaust silencer where they are impossible to access.

Finally, getting around to the questions:
1. Has anyone replaced the hose and found that it fixed a big fuel odor problem?
2. Any advice on how to replace the hose?  (Removing the exhaust silencer looks like it is way beyond my pay grade.)
3. Any advice on finding the source of the fumes?

Sure appreciate any thoughts.

Oh, and a bonus question - I'd like to get access to the area aft the fuel tank someday (to clean the speedo balancing tubes, etc.)  It looks virtually impossible.  Is there a way to do it?

[backfoot100]

Welcome and post some pics of your boat.

Strong fuel fumes would have to be raw fuel being dumped someplace-aka leak. A carb or the tank vent wouldn't cause that without some obvious dripping. The fuel bowls and the fuel lines could indeed evaporate away so strong fuel odors for that long is an issue. You definitely need to investigate where the leak is coming from.

The fuel line actually could be an issue with the new ethanol fuels as the mechanic has told you. The rubber on the old hoses were never intended to be used with ethanol and they can deteriorate causing leaks or fuel delivery issues. I hope the replacement hose you got is marine and ethanol rated? Even if the hose isn't the problem, it's a very good chance that it eventually will be a problem and a good idea to replace anyway.
Yes, you have to remove the exhaust silencer and hardware to get at the fuel line clamps. This is easily done by loosening up a few hose clamps, twisting and yanking a little bit on the silencer and removing it from the exhaust hose that it's clamped to. It probably took you longer to remove the center floor to gain access to the that area of the bilge than it does to remove a silencer. If that's above your pay grade, it's probably best to just take it to a marine mechanic. When replacing the hose, it can be snaked up behind the tank to reattach it without removing the tank.

You should make sure the tank itself isn't leaking either. The tank has an anti-syphon valve at the top of the fuel supply tube that prevents any fuel from syphoning into the bilge in the event of a fuel line break. Even if you have a leak in the fuel line, the anti-syphon valve should prevent any extra fuel from leaking so what is in the hose would evaporate away and the smell would dissipate. That is IF the anti-syphon valve is doing it's job. They've been known to fail too.

As for the balancing tube cleaning, the only way to do that is removing the fuel tank....period. That's not hard to do either but time consuming. Syphon out the tank, disconnect fuel lines, disconnect sender wires and grounds. Disconnect the fuel fill and vent tubes. Remove six hold down bolts on the bottom of the tank and wrestle it out of there. It takes a little "finesse" to do it but it can be done in an hour once the tank is empty.
My question is why do you think you need to clean out the balance tubes? I've owned my A/S for 25 years and 1400 hrs. and I've never done that. 

Hope this helps.

[skibard]

Thanks for the thoughtful reply.

I did proceed with replacing all the fuel hose and vent line hose with marine and ethanol rated hose.  She fired up and ran with no visible leaks.  Time will tell if it made a difference in the odor, but it is good to have it done anyway.  I will continue to look around for any other leaks.

I wonder if there are other concerns with ethanol.  The rest of the fuel system is stainless, so it should be OK.   Maybe there are seals, seats , or gaskets in the Holley Quad that don't like alcohol?

As for the balancing tubes, the problem is erratic speed indication.  One speedo responds quickly and shows a reasonable speed about 90% of the time.  The other one is very sluggish - takes 20-30 seconds to come up to speed after pulling up a skier.  After time it matches the other one about 80% of the time.  I can blow through the tubing between the speedos and the balancing tubes on both sides.  The pitots are clear and have no visible damage.  Both speedos respond quickly to putting a little air pressure on them.  I read somewhere (maybe on this forum) that erratic speedos is a common with contaminants in the balancing tubes.  There is a fair amount of seaweed in the river where I use the boat.  Not a big deal.  I may just bite the bullet and put in a gps speedo.

Thanks again.  It helped.

[skibard]

You wanted some pics.  Is there a separate place to post them?
Here's a few.

[RonT]

The ballast tubes are very simple 1" diameter brass tubes with no moving parts, I suppose its possible that they could collect fine debris that would build up over time, I've just never seen that before. What I do see is freeze damage to the tubes. Have you switched the tubes between the rt & left at the dash? you may have a speedo head issue.