Build up in fuel fill. What is this crud???

[egleas84]

This is a 1983 Mercruiser 120. Popped off the fill an saw this inside.. normal? if not, what can be done? or is this boat screwed!?

 

[JWebber]

Re: Build up in fuel fill. What is this crud???

Welcome to ethanol deposit ash. I have this in my jeep on gas cap. Seem to go away after using sta-bil gas treatment. I also have this in my boat but it's gone due to using fuel treatments like sta-bil. Rub it with your finger it's like ash powder. I don't know what chemical reactions is going on but it leaves a deposit. Alot of people are starting to see this on lawn equipment too! Nothing like corn liquor for gas these days! LOL!

 

[Home Cookin']

Re: Build up in fuel fill. What is this crud???

JW may be right, but I would have guessed salt water corrosion, possibly from condensation collecting there and drying (which could also be from ethanol evaporation) or possibly electrolysis--unusual unless you have any current in that area, such as from your fuel guage.
Anyway I'd get it out with a rag damp with gasoline or acetone, then maybe spray some OB oil in there.

 

[egleas84]

Re: Build up in fuel fill. What is this crud???

no salt water in in Wisconsin ethanol ash sounds like a winner to me. interesting idea with the current coming from the fuel gauge... sounds dangerous.

 

[egleas84]

Re: Build up in fuel fill. What is this crud???

Welcome to ethanol deposit ash. I have this in my jeep on gas cap. Seem to go away after using sta-bil gas treatment. I also have this in my boat but it's gone due to using fuel treatments like sta-bil. Rub it with your finger it's like ash powder. I don't know what chemical reactions is going on but it leaves a deposit. Alot of people are starting to see this on lawn equipment too! Nothing like corn liquor for gas these days! LOL!

a gas station a quarter mile from my house sells 91 octane with no ethanol. i suppose I'll use that! if it keeps happening... hmmmmmmmm

 

[JWebber]

Re: Build up in fuel fill. What is this crud???

I've seen this in lawn equipment, Inside pulse carbs internals. I would like to find the main cause of this.. But sta-bil marine treatment is golden! You would think corrosion form of some type, but it sticks to all kind of surfaces, plastic, metal etc.. etc..

 

[DuckHunterJon]

Re: Build up in fuel fill. What is this crud???

I pulled my snowmobile carbs off this year and found some of this in them. Started looking into it and found out it was biological growth caused by the ethanol. A coworker brought in a petrie dish, and sure enough, the stuff grew. Story was that since ethanol is plant based, it has sugars in it - and where there is sugar, water, and oxygen - there will be nasties growing. I found it came off easy with gum-out and a rag.

 

[scoutboater]

Re: Build up in fuel fill. What is this crud???

I know that the ethanol has been causing a lot of problems in all different kinds of engines. I would recommend StaBil's marine fuel treatment. Its the same as the regular stuff, just several times stronger. It takes care of the ethanol problems.

 

[H20Rat]

Re: Build up in fuel fill. What is this crud???

you guys are over analyzing!

That looks ALOT like frost buildup to me...

 

[egleas84]

Re: Build up in fuel fill. What is this crud???

Bought some of the marine treatment, going to use it to clean it off and then dump some in the tank and then take it to get filled up... then it will wait for "the day"