Fuel tank cleaning?
 

I have a 1991 Formula 311 that will not idle and they think the tank could be rusty and clogged the idle jet, does this seem possible? It runs great over 1000 RPM but will not idle. They checked the timing and choke. The fuel separator had some junk in it that looked like rust particles. Any ideas? Both engines are acting the same.

How old is your fuel? I would change the filters and runit for a bit then dump the contents of your filters into a glass jar and see what it looks like.If its contaminated pull the sending unit out of the tank and look inside with a flash light.If your tank got water/crap in it better clean it out first or you will continue to have the same problem.Most times the crap gets stired up when you run in rough conditions and causes problems at the worst times.If you have junk in your tank it will end up in your carbs.

Thanks for the help. Whats the best way to clean out the tank?

The fuel is old a few years, and we pulled off one fuel filter and it had some particles in the bottom of it that is why the mechanic thought the tank was rusting, but it is aluminum. Would there be another filter going into the carb? And I guess small particles would clog the idle jet?

If the fuel is a few years old then it's likely varnished up the carb bowls. You will need to clean and rebuild to solve that. Since you can't have tank rust the important thing is to get the old fuel out and then look for particles on the bottom. If there is tank varnish the new fuel will eventually take care of that (ethanol cleans stuff really well). Of course all new filters are needed too. There may be a small one right where the fuel line goes into the carb.

There should be a fine acrylic filter in the carb.
Loosten the fuel line and remove the 1" nut and filter is inside. They can rupture and are available at any Boat US or West Marine on the shelf.
Despite junk in the tank it should not get into the carb.
Perhaps water sat in the carb allowing the carb to deteriorate inside (corrode) and that will definitely clog it up.
Water inside a steel filter will cause rust inside the filter and filter may have to be changed more often thanks to our new enemy ETHANOL ! BBB:D

change filters and fuel &run it .

My Cary had the same problem. I tried everything but after clogging up about 20 large fuel filters I started researching fuel polishing. Here is how I fixed my problem.

Sent my four carbs off to Colorado to be rebuilt. I researched fuel polishing systems but couldn't find one for gasoline so I built one myself. Do a search for fuel station supply company. There you will find commercial fuel filters. I pieced together 2 fuel filters (the first 10 micron and water and the second 2 micron). Get a commercial fuel pump. Some assembly required. For the input, use all of your fuel cocks. If you only have 2 engines then you will only have 2 inputs. Hook everything up and filter the fuel from your tank and let the filtered fuel flow back into the tank through your normal fuel fill port.

This completely fixed my problem. For whatever reason there was a bunch of this black fine particulate in my tank.

I bought everything to do the filtering from these folks:

http://www.jmesales.com/item/35552/C...l-Filters.aspx

I used the Cim-tek 800 filters which is where the link will take you. They have everything you need. I bought my fuel pump off of ebay but this is the pump I used :
http://www.absolutehome.com/web/cata...0EAA7B49E0C2FF

Diesel fuel polishing systems are over $2000 and I put mine together for around 550 and 10 hours work.

After I polished my fuel for a couple of hours I took it out and afterwards had clean fuel filters for the first time.

sorry for the long post,
brad

Good idea Rb