Give me methods to determine if the 63-gallon aluminum fuel tank on my 1991 GUARDIAN [UNSPECIFIED MODEL LENGTH] should be replaced?
BACKSTORY
[From sources identified only as] "folks" [conflicting advice on the need to replace the fuel tank has already been given].
[By the visual examination of the outside of the fuel tank, its condition appears to be] "great." No odor of gasoline is detected.
[Presumably from a label on the fuel tank the material is said to be] 0.125-inch 5052 (aluminum alloy) M32 "temp", manufactured in November 1991 by Florida Marine Tank.
The center deck removable section [that covers the fuel tank cavity] is being worked on.
Method to Assess Condition of Aluminum Fuel Tank
Re: Method to Assess Condition of Aluminum Fuel Tank
You have already explored two methods for assessing the condition of an aluminum fuel tank made by Florida Marine Tank, a visual inspection and a smell test. According to your narrative, so far neither of those testing methods indicate any need to replace the fuel tank.
If you closely inspect the label on the fuel tank you should find information on the maximum internal pressure suitable for the tank. This should be a very low pressure, perhaps 2-PSI or less. While observing that maximum pressure limit, you can pressure test the fuel tank to see if there is an indicator of a leak. A leak would be indicated by the inability of the tank to hold pressure for long durations.
There are difficulties in conducting a pressure test. The principal problem is that in order to test only the tank itself, all connections to the tank--the fuel inlet, the vent outlet, the fuel pickup outlet(s)--must be suitably sealed and be holding pressure themselves.
If you plan to perform a pressure test, further advice can be offered regarding how to perform the test and assess the results.
I will offer an additional comment, based on owning a 1990 REVENGE 22 W-T Whaler Drive boat with a 77-gallon fuel tank manufactured by Florida Marine Tank. The fuel tank on my boat appears to be in like-new condition. Visual inspection of the fuel tank by removing the three circular pry-out deck access plates which reveal the upper surface of the fuel tank show the surface of the fuel tank to be free from any decay or corrosion, and remarkably free from dirt or evidence of water. The adjacent foam surrounding the tank (limited only to the starboard side because of the location of the access plates) appears to be completely dry and unaffected by infiltration of water into the foam. There is no sign of any gasoline odor. On that basis, I have NO plan at this time to replace the fuel tank.
Regarding determination of a need to replace an aluminum fuel tank based solely on the detection of the odor of gasoline, such a test is not dispositive of the source of the gasoline leak to be in the aluminum fuel tank. A more likely source of the odor of gasoline fuel will be from permeation of the rubber fuel hoses, particularly the large diameter rubber hose that connects the deck fuel filler fitting to the fuel inlet fitting on the tank, and particularly in the segment of that hose that runs horizontally across from the gunwale to the tank fitting, and particularly if in that hose segment a low spot has developed.
If you closely inspect the label on the fuel tank you should find information on the maximum internal pressure suitable for the tank. This should be a very low pressure, perhaps 2-PSI or less. While observing that maximum pressure limit, you can pressure test the fuel tank to see if there is an indicator of a leak. A leak would be indicated by the inability of the tank to hold pressure for long durations.
There are difficulties in conducting a pressure test. The principal problem is that in order to test only the tank itself, all connections to the tank--the fuel inlet, the vent outlet, the fuel pickup outlet(s)--must be suitably sealed and be holding pressure themselves.
If you plan to perform a pressure test, further advice can be offered regarding how to perform the test and assess the results.
I will offer an additional comment, based on owning a 1990 REVENGE 22 W-T Whaler Drive boat with a 77-gallon fuel tank manufactured by Florida Marine Tank. The fuel tank on my boat appears to be in like-new condition. Visual inspection of the fuel tank by removing the three circular pry-out deck access plates which reveal the upper surface of the fuel tank show the surface of the fuel tank to be free from any decay or corrosion, and remarkably free from dirt or evidence of water. The adjacent foam surrounding the tank (limited only to the starboard side because of the location of the access plates) appears to be completely dry and unaffected by infiltration of water into the foam. There is no sign of any gasoline odor. On that basis, I have NO plan at this time to replace the fuel tank.
Regarding determination of a need to replace an aluminum fuel tank based solely on the detection of the odor of gasoline, such a test is not dispositive of the source of the gasoline leak to be in the aluminum fuel tank. A more likely source of the odor of gasoline fuel will be from permeation of the rubber fuel hoses, particularly the large diameter rubber hose that connects the deck fuel filler fitting to the fuel inlet fitting on the tank, and particularly in the segment of that hose that runs horizontally across from the gunwale to the tank fitting, and particularly if in that hose segment a low spot has developed.
Re: Method to Assess Condition of Aluminum Fuel Tank
Jim is correct and I have found him to be a reliable source of someone who knows what they are talking about vs. someone just postulating.
For what it's worth: I have a 1986 Outrage 18. I've also had a 1983 Montauk and a different 1986 Outrage 18 with a 150 Etec. I bought it for the motor. It had a soft spot(s) on the deck, it had blistering all around the bow, and it listed to port while in the water and at rest. It also had unbelievable performance, at W.O.T. it would "tail walk" because just about the only thing in the water was the prop. The hull had water in it though.
So I found this forum and reading all the posts got me worked up on replacing the fuel tank and such. Ultimately I sold the boat and now I have a 1986 with its original 1986 Evinrude 150 HP. I decided to replace the engine because of its age and after all that I have read, I was fairly certain the fuel tank needed replacing. The process is involved - it was easier for me because I was replacing the engine and I also decided to essentially keep the hull and the bow railing and replace everything else so I would have a new boat. To pull the deck means you have to remove the console. Disconnecting the steering and all the wiring is not that easy. I am replacing everything...I tried disconnecting the steering, watched YouTube videos, and so forth and ultimately used bolt cutters to remove the steering cables.
The deck is heavy, the console is heavy too. My fuel tank had no visible signs of corrosion and no smell of gas. But after reading all of the posts, I decided to pull it anyways. Getting the fuel tank out is a pretty big deal, it's locked in place with foam that has adhered to the tank and the fiberglass.
Once I got everything out - no corrosion. But it's a 1986 and the tank is 38 years old, it MUST be replaced! Says who? That's nonsense.
I also took my boat to the dump and had the truck/trailer/boat weighed on their scale, then just the truck, then just the truck and trailer, and subtracted out the weight of the motor to get a hull weight to see if the hull was holding water or fuel had leaked out and saturated the foam. I never could get the numbers to add up, they always came in lower than the advertised weights.
My original Florida Marine Tank was stamped at 4 psi for a pressure test, which seems really low to me, but that is what it is.
For what it's worth: I have a 1986 Outrage 18. I've also had a 1983 Montauk and a different 1986 Outrage 18 with a 150 Etec. I bought it for the motor. It had a soft spot(s) on the deck, it had blistering all around the bow, and it listed to port while in the water and at rest. It also had unbelievable performance, at W.O.T. it would "tail walk" because just about the only thing in the water was the prop. The hull had water in it though.
So I found this forum and reading all the posts got me worked up on replacing the fuel tank and such. Ultimately I sold the boat and now I have a 1986 with its original 1986 Evinrude 150 HP. I decided to replace the engine because of its age and after all that I have read, I was fairly certain the fuel tank needed replacing. The process is involved - it was easier for me because I was replacing the engine and I also decided to essentially keep the hull and the bow railing and replace everything else so I would have a new boat. To pull the deck means you have to remove the console. Disconnecting the steering and all the wiring is not that easy. I am replacing everything...I tried disconnecting the steering, watched YouTube videos, and so forth and ultimately used bolt cutters to remove the steering cables.
The deck is heavy, the console is heavy too. My fuel tank had no visible signs of corrosion and no smell of gas. But after reading all of the posts, I decided to pull it anyways. Getting the fuel tank out is a pretty big deal, it's locked in place with foam that has adhered to the tank and the fiberglass.
Once I got everything out - no corrosion. But it's a 1986 and the tank is 38 years old, it MUST be replaced! Says who? That's nonsense.
I also took my boat to the dump and had the truck/trailer/boat weighed on their scale, then just the truck, then just the truck and trailer, and subtracted out the weight of the motor to get a hull weight to see if the hull was holding water or fuel had leaked out and saturated the foam. I never could get the numbers to add up, they always came in lower than the advertised weights.
My original Florida Marine Tank was stamped at 4 psi for a pressure test, which seems really low to me, but that is what it is.
Re: Method to Assess Condition of Aluminum Fuel Tank
Jim/Palomino - Thank you for your responses. I really appreciate you taking the time to provide such detailed information.