Leaky fuel tank?
 

Having adjusted the lower shift cable on the trailer last week, I was really pleased to find that it worked perfectly once in the water. The engine didnt miss a beat all day and I had perfect gear changes.

...Until I was about 100 yds from the slipway and I slowed down from about 7mph to about 4mph, the engine started to run unevenly and gradually lost power and then stopped. I left it a while and tried to restart but it wouldnt. Then I put a 5 Gallon can of petrol in and after a bit of effort it started. I am not convinced I ran out of petrol because I filled right up after the last use a couple of weeks ago (I put over 100 litres in) and after yesterdays use would have expected to have used around 50-70 litres. I think the tank is around 150 litres so I should have had about half a tank left so if I did run out, I must have a leak.

I noticed a very strong smell of petrol coming from the ski locker when I was working on the boat last week. Is this normal or would it confirm my suspicions of a leak?

Re: Leaky fuel tank?
 

First off, DO NOT START YOUR BOAT AGAIN until you are sure the leaks is fixed or non-existent. Fuel leaks of ANY kind in a boat causes fuel vapor to settle in the bilge area. All it takes is one spark and the boat can explode.

If you ever, EVER smell fuel inside your boat again, please don't try to start it. You've gotten lucky once, the next time could prove fatal.

Now, the carb starving for fuel could be caused by many things. Check your water separating filter, this would be my first bet on your problem. If you don't know how long it's been on your boat, then it's definitely time to change it.

Since you've been working on your boat, check to make sure there are no kinks in the fuel lines. Also, check the fuel line between the tank and fuel pump, if it's cracked or cut in any way it can leak fuel and cause the pump to suck air instead of fuel.

Also, there should be a clear line running from the carb to the fuel pump, if AND ONLY IF, you don't smell fuel in any way try cranking the engine and see if any fuel appears in the clear line. If there is, your fuel pump needs replacing.

Please be safe and err on the side of caution in your troubleshooting.

Re: Leaky fuel tank?
 

Hi Kylakerat

Thanks for the advice, scary thought.

The smell of petrol only came from the ski locker. The engine compartment had no smell, which made me think it might be the tank rather than a fuel line. I keep the fuel tap turned off when the boat is on the trailer.

Having run the bilge blower for 10 minutes before starting the engine, the smell didnt seem too bad. Absolutly no sign of fuel starvation until the very end of the day (fuel/water separator filter changed a couple of months ago). If it did run out of petrol, I am wondering where roughly half a tank went. Anything in the ski locker drains into the bilge which would have made the engine compartment smell the same. I will investigate further. If all fuel hoses are OK, is there a way of finding out if the tank is leaking - obviously I dont want to put more fuel in until I am sure there is no leak?

Cheers

Grommett

Re: Leaky fuel tank?
 

Never, ever do anything that might generate a spark or flame in the vicinity of gasoline fumes, especially if there are fumes in an enclosed space, such as a bilge or engine space.

I suspect you don't yet have the proper appreciation, or should I say "respect," for petrol fumes. Allow me to put it in perspective: The vapour from one (1) cup (about 1/4 liter) of gasoline is said to have the explosive power of two sticks or five pounds (about 2-1/4 kg) of dynamite.

Btw: Gasoline fumes are heavier-than-air, which is a big part of why they're so dangerous.

I don't know, but you have two issues: 1. Explosion danger, 2. Pollution.

Jim

Re: Leaky fuel tank?
 

Not to sound brash, but it usually has to be leaking to be able to find where it's leaking from. It's almost impossible to find a hole in a tank that is filled with air.

Put it on the trailer and fill it back up to the top. Look and smell for any fuel in the ski locker & bilge area. If nothing, then wait a few days and try to fill it again. If it takes fuel, you have a leak, if no more fuel goes in, then you don't have a leak and you just mis-calculated the amount you had left (happens to the best of us ;) ).

Why were you figuring you had half a tank left and not just looking at the fuel gauge? Did the gauge show as being half full when it died on you?

Oh, and I agree with the other posts, don't try to start it until you're sure you don't have fuel leaking into the bilge area.

Re: Leaky fuel tank?
 

Unless it's pressurized air ;). (I believe that's how the pros do it.)

No offense intended, but if I suspected I had a leak, re-filling the tank would be the last thing I'd do.

His fuel gauge is busted.

Jim

Re: Leaky fuel tank?
 

Thanks to all of you for the warnings, I am new to boating so all your advice is invaluable. A freind who is experienced with boats told me he thought the smell was normal but clearly this is not the case.

Actually Jim, I have a third issue - petrol (sorry - gas) is £1.03 per liter at the gas station and £1.30 per liter at the marina. I think you guys get it a bit cheaper! As you correctly point out, I would rather establish any leaks without filling right up again. I will try and find a way of finding if there is still fuel in the tank. If there is then there is some other reason why the engine stopped.

By the way, when you say pollution, I assume you mean vapour escaping to the atmosphere, is this worse than exhaust gases?

Grommett

Re: Leaky fuel tank?
 

Definitely not normal to smell fuel in the boat.

At that price, it probably cheaper for you to take it in and have it pressure tested (and yes, Jim's right, that's how the pros do it :wink_thumbup:). Here at 2.50 a gallon, it's cheaper & quicker for me to put in the fuel and find out where the leak is than to take it in or buy the tools to pressure test it.

Here's a thread talking about leaks and fixes for them.

Let us know what you find out.

Re: Leaky fuel tank?
 

Unburned hydrocarbons lead to an increase in ground-level ozone creation, which is a major source of ground-level pollution, so yes. (This is why they ask you not to fuel your car on very hot, sunny days.) But I was thinking more of where all that petrol is going. If you're losing that much (yet to be established): Where's it all going? After all, unless I'm mistaken, you're talking about missing gallons of petrol, right? Could some of it be ending-up in the water, somehow?

Jim

Re: Leaky fuel tank?
 

I have had that fuel smell in my ski locker for years. It does not leak, but gas odors will permeate out of plastic fuel tanks.

It's a common problem in many models of boats.

Take care, inspect your tank throughly, but don't be surprised if you don't find a leak.