cleaning fuel tanks

My motors would die as I powered up, so we figured there was some kind of vaccum leak because the carbs were adjusted to factory specs. After draining the tanks and examining the pickups, they crumbled like potato chips and since the bottom screens were broken off, you could surmise that the small fragments could easily be sucked into the fuel lines. Also, since we don't know how much of the one pickup was broken off from the top of the starboard tank, this could also have affected the acceleration problem when the boat and tank and fuel shifts on acceration. Plus, after changing the primer bulbs, I noticed that they would now prime hard before starting both motors. And finally, when I changed to both new Yamaha fuel connectors, they would engage where you would feel and hear the snap when plugging them in, thus giving me the confidence that there were no air or fuel leaks. I purchased my boat back in October and the prior owner had not given it much use and although the motors had only 100 hrs each, I would have been far better off to have first checked the tanks and changed the hoses, fittings and filter. Anyone who has plastic pickups, should definitely change them out right away!

Hope this helps.

Vern
 
In reading some of the latest posts it would seem there is a problem with the fuel pickups in boats around the same age as mine
so I think I'll be removing mine for inspection.
back in nov not long after buying the cd I tried removing the fuel tanks with not much success. I was unable to get the large fill tube off the top of the tank it almost seemed like it glued onto the post. Has anyone else had this problem?
I should have time next weekend to give another go, I was thinking about cutting the intake line but then I'm left with problem of replacing it.

if some how I manage to get the tanks out how would I go about removing the fuel pickups?
 
I found the easiest way to remove tanks is to first siphon as much gas as possible. Remove both starboard front covers. Then take some silicon spray with a tube and spray lightly between the connection of the black fuel hose to the male fuel tank inlet after removing the clamps. Do this for both the fuel and air lines. Then tilt up the section of the tank closest to the center of the boat and twist gently until you free up the fuel and air lines. Once you free the lines, get a pry bar and gently pry both hoses off, they should come off fairly easily and then the tanks will easily slip over the starboard tank strips. My mechanic ordered the pickups but I believe you should be able to easily find them at most online marine stores. If your pickup has disintegrated (like mine did), after you get all the large pieces out, take some air and blow it dry. I then took a shop vac and put a smaller hose taped to the main hose and sucked any small remaining particles in the tanks.

Vern
 
Next question:

When reinstalling the pick up tubes, how far off the bottom of the tank should the intakes be placed?

I assume they can be cut to the desired length and the filter/screened intakes replaced on the tubes.

Too long and they'll pick up debris or water in the bottom of the tank, too high, and they'll waste fuel capacity by not picking up as much fuel as practically possible.

As a guess, I'd say 1 to 1 1/2', but I wonder what the directions (if any) on the pick up tube box says?

Joe. :teeth :thup
 
For those who are going to be removing or working on fuel tanks, or changing out fittings, here's a suggestion: be VERY careful.

The fuel/air mixture inside gas tanks can be explosive, which is why spark arrestors are required. Although the tank is plastic, not metal, it's still capable of providing everything but the spark needed for an explosion. I would be particularly concerned about purging the tanks with air (which can introduce a static discharge to an accidentally grounded fitting), or sucking them out with a shop vac (which can introduce a spark in the vac, and a flame which would travel back to the tank).

I don't know if there is an accepted procedure for making a plastic tank safe to work on, but if you have any reason to believe that the vapors in the tank could possibly be ignited, you might consider filling the tank to overflow with water, and then removing only enough water to allow you to do the work. Once the work is completed, remove the rest of the water. The reason for not removing all the water at once is that plastic absorbs and is itself a source of vapors, and that sometimes you think you’ve purged all the gas out, but have managed to miss a little pocket. If you decide to drain all the water at once, you're still going to be way safer than had you not put the water in the tank to begin with. Draining the water onto an absorbant pad will catch any fuel or "gunk" that the water removes from the tank. If any water remains in the tank afterwards, it can be removed by letting the tank sit in the sun, or via the fuel/water separator.

I once did work for the wife of a poor fellow who managed to ignite what he thought had been purged from a tank. He hasn’t been doing boating, or much of anything, ever since.
 
Rick:

I checked our log book, and the Rideau Boating & Road Guide, and found that the hesitation/stall problems I experienced began immediately after taking on gas at Aylings Boatyard, Merrickville, Ontario, on Saturday, August 25, 2007. This was before the long run to Pirates Cove, and the first time on our trip where the motor acted up.

As I recall, I radioed after the hesitation began while cruising. Then, it took the form of hesitation when advancing the throttle. I seem to recall that you or Dun had noticed something after taking on gas, but not as pronounced as I experienced. When we got to Pirates Cove, I got a full stall after waiting at idle for a slip, and then throttling forward.

I have several theories on what's causing this, but want to try out one adjustment to the motor before having that discussion. Any of this jog your memory?

david
 
Hi David,

Yes, I was thinking of that fuel stop when I suggested correlating mutual fuel stops with the hesitation. I also remember some other mutual fuelings and got the data from my log.

8/25/07 - Peter Ayling Marina at 1545, then we cruised thru 4 locks and stopped for the night at 1900 at Pirate’s Cove. I don’t remember that I had any engine problem, and there is no entry in my log.

9/14/06 – Just before Waterford, you and I got gas about 1600, before entering the flight of 5. No mention of engine problems in my log.
9/11/06 - Marina at Brewerton where many of us got gas along with showers in the AM. Then we crossed Oneida. No problems noted.

9/14/05 – Pittsford got gas at lunch time at the convenience store just before center of town. No problems logged.

Rick
 
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