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Gert's post got me thinking about this: I'm taking a look at a 1977 bahia mar this weekend and my major concern with it is the fuel tank (gas engines). She's been in California for a long period of time (over 10 years) so she has been exposed to ethanol in the fuel - however, the current owner (purchased her in 2008) states that as far as he knows the tank is original.

Current owner uses ValvTect fuel, which contains ethanol, but has not reported any problems with pushrods being trashed, leaks, delamaniation, etc.. What can I check to see if the tank is ethanol approved? I can't look for a tag or stamp on the tank since it has been painted over. Maybe check for soft spots? Is there any way to know for sure if the tank is ok with ethanol (aside from opening it up and taking a look inside)?

Minimum of 5.7% up to a max of 10% of ethanol has been required to be in all fuel sold in California since 2004. Could this explain why the tank has not failed or started delaminating? Because it's less than 10% and that in itself will decrease the effects on the resins used to make the tank? Even Vavltect states 10% is a problem in older fiberglass tanks (http://www.valvtect.com/fileshare/docum ... 5-2009.pdf)

Just some random thoughts and hoping for some insight from the knowledgeable folks here.

John

10% is what has been in the midwest for a while now. It is enough to cause problems. I think what you will find as the concensus around here is maybe not today, maybe not tomorrow but at some point it will rear it's ugly head and then you will wish you jerked the tank and replaced it with a stainless, aluminum or best choice a vinylester (I think thats what it's called ask Capt. Patrick) tank. There is a link around here somewhere to the manufacturer. Not cheap but dependable.

my$.02

I had a problem with my tank early on...1962 Original glass tank.

It was so early on nobody knew what to look for. I Opened my inspection plate and tank looked great...still pulled all fuel out and cleaned it best I could and replaced with fresh fuel...only to have the same problem. Tank was real clean on the inside....apparently too clean. No soft spots...I don;t think you could check tank that way.

I believe some guys had fuel samples from the tank checked that showed a level of chemicals that make up the resin and then it was pretty clear what was happening. I know Boat US asked about me giving them a sample, but they had someone closer.

I think the easiest way to diagnosis the tank breakdown is to look at one symptom in particular. Pull a spark plug...the resin turns the plug end into a mass of Black Goo. Similar to carbon buildup, but gooey and sticky without the smell of oil or fuel. You could also pull the intake and carbs...on these you'll see a thick Black Coating that just won't want to come off, again like carbon buildup, but you can stick your nail into it...but the plugs are quick and easy check.

My problem with using one fuel location..what if you travel, fuel dock gets a 10% blend on mistake...For me if tank is fine...keep an eye on it with expectation you will be changing. If I'm wrong...good for you.

I test all gas before I put it in my boat. It only takes 5 minutes!!

Rawleigh wrote:I test all gas before I put it in my boat. It only takes 5 minutes!!

What are you testing for?
If ethanol, what do you do when your at the only fuel dock and need fuel with a positive result?

Or checking for water, particulates and algea which can be filtered out.

Checking to make sure that the fuel does not contain ethanol!!