Fuel tank cleaning

[SubtoSail]

I would like to give my fuel tank a cleaning. It’s been at least several years, if ever. The tank is white plastic and ratchet strapped down to a 2x4 cradle. I could try to wrestle it out, but it would be much easier if it can be done in place. What’s the best way to go about this?

I could use the mechanical fuel pump to drain the tank, but I think I’m more likely to use an outboard style squeeze bulb. A few cycles of fill and drain with some type of cleaner?

How often do we think this should be done?

Thanks!
-Joe

[prstack7]

cleaned tank in place

I cleaned my Monel tank in place 8 years ago. I pumped all the old gas out with a mechanical siphon pump through the fill tube, then filled with a gallon of acetone, sloshed it around by rocking the boat, then pumped that out, getting the last bits out with a rag (my fill tube goes straight down to the lowest point of the tank). I don't know if a plastic tank should be cleaned with a different solvent.

[TimBSmith]

Here is what I did to sample, filter, and then clean tank in place.

Inspired by others here I filtered and scrape tested my monel tank this fall to see condition of fuel and tank.

Filter and scraping rig

https://photos.app.goo.gl/kzhjGWWnZNce86HQ8

I used the pvc pipe to scrape the bottom of the tank to see if sediments appeared. They did not. If they had, I would have agitated tank in addition to adding cleaning detergent and soaking.

Here is what I added to tank to soak for 2 days before filtering.

https://photos.app.goo.gl/jESiFaGLHnqC6bGdA

If I needed to agitate. I planned to used a small palm finish sander to externally agitate the tank all around from below deck. Pearson 30 tank access. I would have done 2 one hour session over 2 days and checked again after filtering.

After soaking, here is what the filtering process looked like.

https://photos.app.goo.gl/6syyeCvL5vBBQUhNA

There is a fine filter before the intake on the pump I bought. There is a gross filter that I added upstream. Don't recall the micron rating for either. I found very little passing through.

I also tested electronic fuel pump function while I was at it. Jumped the oil pressure safety switch.

https://photos.app.goo.gl/wNjZmtjAGQdVWpje7

I was fortunate. All evidence upstream fuel system in good shape and found that PO had replaced fuel lines recently.

Before buying this boat I had little to no experience with engines. Initiative, study time, this forum and Moyer Marine have taken me a long way safely effectively and quickly. Here is the entire album of my upstream fuel system adventure. I have not gotten around to captioning key pictures yet.

https://photos.app.goo.gl/pDpgEJST4Kj2GF9B8

Happy holidays.

[Al Schober]

I would NOT put any solvents into a plastic tank. Soap & water should be OK. If brave you could try the Zep Purple stuff, but thats alkaline and eats aluminum - not sure what it would do to poly.