Sending unit glue / compound

[Weso]

My 22 Seafarer sat for over 6 years I jacked the front up siphon everything I possibly could from the pick up. I put like 10 gallons of 91 in it. Ran great but I'm getting to the bottom of the tank and it's acting up the motor. I'm thinking pulling the sending unit and just cleaning the tank out that way. What do I use to seal back up? I'm not seeing any sight of a hole just the guy I bought from left it half full for all them years. Like milky substance. I bought new fuel/ water separate with clear bull that drains. Bought couple inline filters.

 

[Hookup1]

Like milky substance.

Is this on top of the tank or what is in the fuel filter bowl? Water and crud in the tank is on the bottom and comes out first. Whats on top is fuel. Tanks are difficult to clean in place. I would get setup and work the filters hard.

Here is a previous post I did on the subject...

If it ran for 20 minuets then died you immediately need to pull the filter can off and dump into a somewhat clear plastic quart container (West, Home Depot or takeout). Or a glass jar as seasick said. It will take less than a minute for the fuel to separate from the water.

It's difficult to get all the water out of the tanks at the dock. I found that running the boat and bouncing around gets the water somewhat in suspension where the pickup in the tank gets fuel and a little water up into the filter. Remember the water sits on the bottom of the tank and the fuel floats. And it takes a while to fill the fuel filter up with water - maybe 20 minuets in your case.

Once it stalls you need to get the water out of both the can filter and the one on the engine. I bring a small can of gas with me and a disposal container (orange juice bottle). Dump the filter can into a container, give it a minute, dump only the fuel back in the filter, top off a little with fresh fuel and put it back up. Same with the filter on the engine. Pull cowling off, unscrew filter, dump into container, give it a minute, dump only the fuel back in the filter, top off a little with fresh fuel and put it back up.

I don't really like messing with fuel out on the water but its the only way it works for me. Always have someone with you and a good fire extinguisher handy.

The alternative is to run the boat for a while, shut the motor down, inspect the bowl on the Sierra clear bowl. If you see water tap it off into a container. Start more back up and run around. Re-check again.

It's really important that you deal with the water in the larger filter can BEFORE it gets up into the engine. Otherwise you will stall the engine and have a hard time restarting it.

 

[Legend]

The sending unit has a rubber gasket that comes with the unit, unless the tank is in rough shape that should be adequate to seal it. If the gasket does not seal it completely there are sealing compound that are made for sealing gas. Do not use silicone products as gaskets.

 

[SeaVee]

Personally I’d bite the bullet and get the fuel professionally polished. I bought a 265 that the prior owner hadn’t used the Aux tank in 13 years. Was about 1/2 full ( 130 gal tank). Was about $400.00. USA Fuels did it, I think they are nationwide.
To answer your question. I used this stuff and it is working great. Be extremely careful removing the sender screws, if you get too rough with them you can damage the tank:

 

[seasick]

My 22 Seafarer sat for over 6 years I jacked the front up siphon everything I possibly could from the pick up. I put like 10 gallons of 91 in it. Ran great but I'm getting to the bottom of the tank and it's acting up the motor. I'm thinking pulling the sending unit and just cleaning the tank out that way. What do I use to seal back up? I'm not seeing any sight of a hole just the guy I bought from left it half full for all them years. Like milky substance. I bought new fuel/ water separate with clear bull that drains. Bought couple inline filters.

There is some risk when removing a sender. Usually I don't recommend that unless the sender flange leaks or the sender needs replacement.
If you remove it and all the screws come out without incident, the challenge is the condition of the tank flange and to an extent the sender flange assuming you are not replacing the sender. Do not reuse the gasket, get a new one. If the tank and sender flange are relatively clean and not corroded, a simple clean up with sand paper should do. If again, the flanges are smooth and clean, no sealant is required, just a new gasket. Do not over tighten the screws.

With respect to the motor issues when the tank level gets low, that can be a few different things, You could have gunk in the tank or perhaps water. Before removing the sender, inspect the gas filter on the motor and also remove the gas filter/water separator and pour it's contents into a glass jar. Let it sit for 10 minutes or so to see what settles out if anything.
What you are doing is looking for evidence of water or crud.
Your problem may not be crud but rather may be weak fuel pumps. As the gas level gets lower, the pumps have to work harder to suck up fuel.
If your motors act up on low tank levels try running at slow speeds ( hull plowing, not on plane) to see if the motor issue clears up. If the problem happens only on plane and when the tank is low, gunk in the tank is a good possibility

 

[Weso]

My 22 Seafarer sat for over 6 years I jacked the front up siphon everything I possibly could from the pick up. I put like 10 gallons of 91 in it. Ran great but I'm getting to the bottom of the tank and it's acting up the motor. I'm thinking pulling the sending unit and just cleaning the tank out that way. What do I use to seal back up? I'm not seeing any sight of a hole just the guy I bought from left it half full for all them years. Like milky substance. I bought new fuel/ water separate with clear bull that drains. Bought couple inline filters.

 

[Weso]

I think I need to keep working the tank. I will drain the fuel separater and inline filter. Frustrating cause I'm itching to hit the islands for White sea bass and I don't want to break down across the channel.

 

[everwhom]

This is the gasket I just used for my replacement sender (assuming you have the standard 5-screw mount): https://kus-usa.com/product/gasket-mounting-kits/
I got the "Viton" gasket on the assumption that more expensive was better

 

[Weso]

This is the gasket I just used for my replacement sender (assuming you have the standard 5-screw mount): https://kus-usa.com/product/gasket-mounting-kits/
I got the "Viton" gasket on the assumption that more expensive was better

Thanks

 

[Legend]

One other tip, if you remove the sender mark a line on the tank and the sender so you know how to replace it. The screw pattern is very specific and you can damage the holes if you do not have it aligned correctly