Sending Unit Leaking

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Would be curious to know if any 310 owners have fuel guages that actually work and are accurate?
My 2003 still works and is fairly accurate.
Would be curious to know if any 310 owners have fuel guages that actually work and are accurate?
My 2003 fuel gauge works ok. Depending on sea state and heeling angle, the readout can vary quite a bit, of course. I still keep track of how many hours I have motored since the last fill up, and figure 1/2 gallon consumption per hour. So far, my estimates of fuel use and the readout of the gauge at rest seem to agree pretty closely. Unfortunately, our fuel tank installation makes using a dip stick impossible.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
I take it the opening on the top of the tank is standard size,
The opening in the tank was cut (by Catalina) to accommodate whatever brand of level sensor was installed. If you buy a different brand of sensor, you have a different sized opening.
 
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
WEMA, when I purchased mine, offered different sizes and configurations so I was able to match my tank configuration.
 
Aug 23, 2020
27
Catalina 310 323 Mamaroneck
First, thanks to everyone who gave me advice on the sending unit - much appreciated. Last Sunday I pumped about 2.5 gals of diesel out of the tank, tightened the existing flange/gasket back in place and cleaned her up. Yesterday I went to the boat and found the paper towels I left on the sender unit's flange bone dry, do the leak is stopped it's good for the winter. Diesel smell is almost completely gone. My plan is to replace the gasket in the spring, when I'll have access to water again (my club shuts the water down this weekend for the winter months) so it doesn't leak when I'm heeled over and the fuel level reaches the gasket next season.

I put a zip-lock bag under the primary fuel filter to see if that was also leaking, and I found a few drops of diesel in the bag yesterday after 5 days, so that also needs addressing. If I can't just tighten down the fittings on that to prevent it leaking, I might just bleed that line for the winter. Any other suggestions on the fuel filter? Since I'm new to this, I'm still learning how they work and what adjustments might.be needed.
 
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Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
Sounds like you are doing it right. It is a learning curve. Appears you are on the positive side of the graph. Keep exploring and asking the questions. Not sure about your area, but in the PacificNW, I go to the boat and just sit and examine all the little things I ignore when I am racing to get out on the water. You will be amazed at the way the boat is put together exploring the voids that all boats have.
Have a good winter.
 

Tom J

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Sep 30, 2008
2,301
Catalina 310 Quincy, MA
Any other suggestions on the fuel filter?
I doubt that the fittings would be leaking. There is very little pressure on them but it would be wise to double check them, since you don't want air getting sucked into the system. Most likely one of the gaskets on the filter canister is weeping. When you install the new filter, rub some diesel on the gaskets before installing the filter.
 
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Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
rub some diesel on the gaskets before installing the filter.
:plus: You might also take a rag or paper towel and be sure the filter base where the gasket sits is clean of all debris. A grain or two of sand can create a path between the metal base and the gasket for air or fuel to escape.
 
Mar 6, 2008
1,078
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
My leaky primary filter turned out to be missing paint at the bottom where the rubber gasket ring tests. This uneven surface provided path for the fuel to leak out. I removed the upper bracket and sanded the paint off completely around the ring with 400 grit sandpaper. After cleaning there was no more leaking.
 
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BillyK

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Jan 24, 2010
502
Catalina 310 Ocean City, NJ
i had 5 gallons of diesel in my bilge last winter from a failed tank. tried every cleaning product known to mankind with no joy in getting the smell out of everything inside the boat. It happened over the winter so the diesel just sat for months unnoticed giving it a serious chance to work its smell into everything..
After cleaning it all out and flushing the bilge several times with dawn/simple green/pure ayre, and then cleaning everything in the cabin, the ONLY thing i was finally able to get the smell out with was, believe it or not, essential oils.. i picked up one of those nebulizer style vaporizers.. i ran cinnamon, tea tree, rosemary and lemon oil mix with every door, cabinet, floor hatch and cushion propped up to all all sides to get treated. i ran a fan to move the air around and nebulized 1 fl oz of the oils inside the boat with the doors and windows shut.. i let that sit for 3 days and then opened everything up for fresh air.

the diesel smell was gone. and what was left was the best smelling boat i've ever been in.. in fact, it stayed fresh smelling through the entire summer. i'm planning on treating the boat again like this in the spring.
 
Aug 23, 2020
27
Catalina 310 323 Mamaroneck
...and what was left was the best smelling boat i've ever been in.. in fact, it stayed fresh smelling through the entire summer. i'm planning on treating the boat again like this in the spring.
While I'm thrilled that you ended up with the best smelling boat, I'm truly sorry you had to have that experience. I've stopped the diesel smell for now and have removed all cushions / mattresses for storage at home while I clean those. I will definitely try the nebulizing essential oils - great way to get my wife to enjoy the boat more!
 
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