ALMOST BLEW UP MY GAS TANK...READ THIS!

Gas fumes in an open bilge (unlimited oxygen) would reacts much different than it would a confined tank. I could see a lack of oxygen in a tank full of baffles not exploding. Sounds like the op dodged a big one.
Post a pic of the sender if you can. If the tank got as hot as you described, it would be coming out for inspection and testing if it were mine.
 
Creekwood said:
And it makes no sense that 12 gallons of gasoline would be boiled away by current coming from a gas gauge sending unit. That much current would melt the sending unit wire. And the boat would have blown up. Any heat source strong enough to boil away 12 gallons of gas would absolutely have ignited the boiling gas vapor. This all sounds very strange.
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12V no less
 
As LD pointed out, the wire should be pink and not red. The light wire and potentiometer on a fuel sender is meant to handle milliamps. Bet it would light up like a cig lighter if a high amp or unprotected circuit was connected to it.
 
now that i know its possible to access without pulling water tank, and seeing this thread, i will let the mechanic deal with it. best case, it gets fixed. worst case i call Geico and buy that 450DA for sale in another thread after this one blows up.
 
FredM said:
I removed some old gas in my tank. I put in 12 gal of new gas and began to crank it until it got thru the system.
I heard something that sounded like boiling. Then hot fumes started belching from my gas weep hole. I rapidly cut off all power and got off the boat until things cooled down. The entire 12 gal. was gone. The inside of my gas tank was scarred.
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Come on Maaan.:rolleyes:
 
Creekwood said:
And it makes no sense that 12 gallons of gasoline would be boiled away by current coming from a gas gauge sending unit. That much current would melt the sending unit wire. And the boat would have blown up. Any heat source strong enough to boil away 12 gallons of gas would absolutely have ignited the boiling gas vapor. This all sounds very strange.
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Thank you very much for your insight.
 
Creekwood said:
And it makes no sense that 12 gallons of gasoline would be boiled away by current coming from a gas gauge sending unit. That much current would melt the sending unit wire. And the boat would have blown up. Any heat source strong enough to boil away 12 gallons of gas would absolutely have ignited the boiling gas vapor. This all sounds very strange.
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Thank you very much for your insight.
Currently I am reviewing every detail of the installation. I will be checking with Sea Ray local and corporate for some answers. A very small amount of resistance can cause a great amount of heat, especially when aluminum is the carrier. I totally understand your reasoning about the sending wire melting. But the tank got hot. There is a reason why Sea Ray changed grounding of the sending unit to include a ground wire connection in later model boats.
 
Pirate Lady said:
now that i know its possible to access without pulling water tank, and seeing this thread, i will let the mechanic deal with it. best case, it gets fixed. worst case i call Geico and buy that 450DA for sale in another thread after this one blows up.
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I will learn the answer soon about this fiasco. I will keep you posted.
 
FredM said:
Thank you very much for your insight.
Currently I am reviewing every detail of the installation. I will be checking with Sea Ray local and corporate for some answers. A very small amount of resistance can cause a great amount of heat, especially when aluminum is the carrier. I totally understand your reasoning about the sending wire melting. But the tank got hot. There is a reason why Sea Ray changed grounding of the sending unit to include a ground wire connection in later model boats.
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You're contacting SR corporate regarding an issue installing an aftermarket part on a 30 year old boat?

And yes, a small amount of resistance on a very high amperage circuit could *potentially* create some heat, but this isn't a high-amp circuit.

I'm not saying you're trolling, not saying that your experience wasn't a bit frightening, but there's a huge piece of information that is lacking here.
 
Lazy Daze said:
Re-read my response.
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I am contacting SR on the non use of the ground tab on the sending unit in 1990 vs the use of it now. It has nothing to do with an after market part. No ground wire was provided in the 1990. You have a ground wire today. I want to know why.
 
FredM said:
I removed some old gas in my tank. I put in 12 gal of new gas and began to crank it until it got thru the system.
I heard something that sounded like boiling. Then hot fumes started belching from my gas weep hole. I rapidly cut off all power and got off the boat until things cooled down. The entire 12 gal. was gone. The inside of my gas tank was scarred.
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FredM, how long were you cranking it over? How do you know the fumes from the vent were hot?
 
Woody said:
FredM, how long were you cranking it over? How do you know the fumes from the vent were hot?
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Stuck my hand to the vent above the filler. The gas was very hot coming out of the vent.
 
FredM said:
I am contacting SR on the non use of the ground tab on the sending unit in 1990 vs the use of it now. It has nothing to do with an after market part. No ground wire was provided in the 1990. You have a ground wire today. I want to know why.
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Re-read my post.
 
FredM said:
Stuck my hand to the vent above the filler. The gas was very hot coming out of the vent.
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The vent is below the fill. Where exactly where you sticking your hand?
 
Lazy Daze said:
The vent is below the fill. Where exactly where you sticking your hand?
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Friend,
The vent was whistling for no reason. I put my fingers at the vent hole where it was whistling, and hot gas (not liquid), was coming out the vent with so much force that I could not stop it. That's when I raced to cut off all electrical and abandon the boat.
I am an industrial engineer and an x- ham operator. I have experience with electricity traveling backwards thru grounds. I have a close friend who owned a Sea Ray Sundancer and is a certified Master Electrician. I will be contacting him today to discuss the incident.
 
Geez. Whatever happened I’m glad it wasn’t at a marina.

Sounds like you built a bomb.
 
FredM said:
Friend,
The vent was whistling for no reason. I put my fingers at the vent hole where it was whistling, and hot gas (not liquid), was coming out the vent with so much force that I could not stop it. That's when I raced to cut off all electrical and abandon the boat.
I am an industrial engineer and an x- ham operator. I have experience with electricity traveling backwards thru grounds. I have a close friend who owned a Sea Ray Sundancer and is a certified Master Electrician. I will be contacting him today to discuss the incident.
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Lazy Days gave you your answer why a ground was added to later fuel senders. Its because use of poly tanks become much more common and the sender needs to be grounded to work.

You said 12 gallons of gas boiled off. Are you sure of that? That makes no sense. Even if the sender/ground had enough gauge of wiring and had a direct short, it would heat only the area where the ground is mounted or at worst the sender top unit. That heat would not heat the full tank, it would heat the top only, and would not boil the whole gas tank off. And that much current would burn through the wire.

And aluminum is a very good conductor. You could connect jumper cables to your batteries and on each side of the tank and it would not heat up with that amount of current going through it. It might spark at the connection point if it was a bad connection.

So if this did happen, there is something else going on. By any chance do you owe a lot of money to the mob?
 
Creekwood said:
Lazy Days gave you your answer why a ground was added to later fuel senders. Its because use of poly tanks become much more common and the sender needs to be grounded to work.

You said 12 gallons of gas boiled off. Are you sure of that? That makes no sense. Even if the sender/ground had enough gauge of wiring and had a direct short, it would heat only the area where the ground is mounted or at worst the sender top unit. That heat would not heat the full tank, it would heat the top only, and would not boil the whole gas tank off. And that much current would burn through the wire.

And aluminum is a very good conductor. You could connect jumper cables to your batteries and on each side of the tank and it would not heat up with that amount of current going through it. It might spark at the connection point if it was a bad connection.

So if this did happen, there is something else going on. By any chance do you owe a lot of money to the mob?
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There are WAY too many tangents here.
The amount of gas boiled is strange to me. I left the boat for overnight. The use of poly tanks for a ground wire is obvious.
I simply asked if anyone had this happen to them. I didn't ask if anyone thought I was crazy. SMILE.
I just got off the phone with my Master Electrician pal in South Carolina. Aluminum wire is no longer allowed in houses due to additional resistance.
The aluminum tank also acts as a diode due to its resistance, meaning it keeps voltage flowing in the right direction. When I added a jumper from the ground of the sending unit to the ground terminal of the gas tank, I bypassed the resistance barrier of the gas tank. Voltage flowed backwards thru the gas tank and heated it up.
The discussion of how much gas evaporated is a rat hole. I can't solve that mystery.
I simply know what I did and now I know why it happened. Now the solution may be disputed by some very good, knowledgeable, folks. Granted it is a theory backed by experience.
I am trying to go the extra mile to support the validity of my experience.
One gentleman asked for pictures. I am composing those.
I will repost this article with pictures probably under a title something like "installing aftermarket gas sending unit in a 1990 Sea Ray". Give me a week.
 
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