Fuel Level Sight Glass Replacement?
 

My fuel level sight gauges are old and completely opaque, can't see a thing even with back lighting. What is the proper tubing to use to replace them?

You will get lots of suggestions here. When I replaced mine on two tanks I used tubing from West Marine; the same stuff used for water. Although others will criticize my choice, I’m happy to report that after 7 years they are still in service and perfectly clear. Cost was minimal. I do have shut off valves at top and bottom of the tubes which remain closed unless I’m reading the fuel level. BTW, the “proper” tubing is Tigon.

Howard

Tygon perhaps?

Perhaps.

I use the same re enforced water pipe for a small tank that feeds the boiler. While mine aren't clear, they can still be read easily enough. Whatever type one uses, it's important to have shut off valves in place top and bottom when not being used to measure tank levels.

Clear PVC is probably fine. Because it is so easy and cheap to replace, its likely not worth doing anything more. Even the "better" alternatives will still melt and spill fuel in a fire situation. But, if you're so inclined...

Below is what I have just installed. (I'm still fabricating the guards and indication markings, so they haven't even seen fuel yet.) Meet up with me in 15-20 years and I'll let you know if it was worth the effort :lol:

Tygon (and Versilon) are brand names that refer to a multitude of different tubing, all with different properties and not all rated for hydrocarbons.

What you want is one of them formulated for what you intend to put in it. I bought mine from McMaster-Carr, about $20 for two 2 FT pieces that made up both my sight gauges. They were one outfit where I could buy a reasonable length (less than a 50 ft roll.) The tubing is specifically rated for use with diesel fuel. Its basically the same clear PVC tubing you can get at a local store, but has a thin inner liner of another clear polymer that has the chemical resistance...In this case FET, which resists a lot of dang stuff.

Here's a pic of the material installed as my stbd side sight gauge (still waiting completion and installation of the guards and markings for level indication.)

Attachment 83969

Below are the details from the the McMaster-Carr website.
_________________________

Ultra-Chemical-Resistant Versilon PVC Tubing

Formulation: SE-200
Very Flexible
Compatible Tube Fittings: Barbed
Soft (Durometer 65A)
Temperature Range: -30° to 160° F
Formerly known as Tygon, this tubing is lined with FEP (fluorinated ethylene propylene) for better chemical resistance than PVC alone. Tubing is clear, so you can easily monitor flow.
___________________

Here's the part number and cost to ship to me in the PNW.
___________________

David Bowman placed this order.
Line Product Ordered Shipped Balance Price Total
1 6519T14
Ultra-Chemical-Resistant Versilon PVC Tubing 3/8" ID, 9/16" OD, 2 ft. Length 2
Each 2 0 9.64
Each 19.28

Merchandise 19.28
Sales Tax 2.44
Shipping 8.78
Total $30.50
Payment Received 10/12/18 (30.50)
Balance Due $0.00

Thanks for the detailed info. This question was driven by my paranoia about what I don't know will kill me. What I have for gauges now is some sort of tubing with cross hatched reinforcement. I guess fuel line of some sort. Wasn't sure why reinforcement was necessary on this.

Tygon F-4040-A :thumb: eBay and Amazon sell various sizes. When we replaced our fuel tanks we used Tygon.

https://www.usplastic.com/catalog/it...x?itemid=23487

Tygon for sure. It is constructed with a liner that is impervious to fuel. This is true, I replaced mine 10 yrs. ago, still perfectly clear. The PVC tubing I removed was yellowed and nearly opaque. SE-200 is available from McMaster. It's apparently now marketed as Versilon.

We just replaced our TygonnF-4040-A site tubes after 4 years. It got to the point I couldn’t see through them without a light behind them. :facepalm:

I went with the Versilon SE-200 that Steve recommended. The change over went good with the exception of figuring out how to slip the hose on the hose barb without detaching the lining from the tubing. I ended up using a small tapered plug to slightly enlarge the hose first.

Here’s a before and after. The first 5’ section I ordered was kinked and the lining had separated. McMaster-car overnighted a replacement at no cost. Five feet was $42.57 including tax and shipping.

That looks great. Congrats

Is there a standard size tubing for fuel tanks or a size that is most often seen? I haven't done anything with mine yet and keep forgetting to measure. Would measure before buying but just curious.

I owe it all to Steve on Maerin. :thumb:

I don’t think there is a standard. Ours happen to have 1/2” hose barbs. Easy to check though. I just pulled the hose off the upper hose barb and measured. To change out, I opened the lower ball valve and blew the diesel back into the tank and shut the valve. I didn’t spill a drop.

Most tubing will yellow and/or become brittle over time.

I use clear polyurethane tubing for sight gauges.

I used clear fish tank tubing 2 years ago. I keep an eye on it but is good so far.

How did you blow it back into the tank?

With my mouth. I took off the top hose and as i was blowing back, I shut the lower valve off. Our tanks were less than half full. It was like blowing bubbles and very easy:D

Thanks. I was thinking that given a low level of fuel, gravity, etc. it would be pretty safe to do that.

In the 14 years that I owned my boat I never looked at the sight tubes other than to make sure they weren't leaking.