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Hi,

I'm rebuilding my fuel pump (kit from Merrit) and I am soaking it in a gallon of chem-dip. I noticed that when I removed the parts and wiped them clean, there is a light black/grey "film" that is coming off. Are these parts anodized/plated? I'm figuring that the the answer is yes.

I wasn't going to scrub these parts to be spotless. Do I need to be concerned that this stuff will gum up the fuel system?

Thanks,

Mark

Do you know the chemical components of your "chem dip"? Major ingredients indicated on the label? The fact that it's leaving a black "smut" indicates that it's acidic and perhaps attacking the base metal. Unless you know it's intended for such alloys and metals it's much safer to stick with a solvent cleaner like carburetor cleaner or something like Brake-Kleen.

This is the Berryman chem-dip carb cleaner. I used on the carb rebuild (WDO). I didn't notice anything on that.

Here it is -->berrymanproducts.com/products/eco-friend ... m-dip-carburetor-and-parts-cleaner/

I looked at the major hazardous components listed (those at greater than 1%) on the MSDS sheet, looks like it should be suitable for a fuel pump. No explanation for the black smut. Did it rinse right off? Any signs of attack on the alloy?

Probably zinc oxide. I would put a penny in the stuff and see if it disolves.

Zinc oxide is white to yellowish-white.

I'll try to take a picture of it. I did notice that the dip removes rust. ...as there was some in the bottom of the bowl. Wouldn't it have to have something acidic for that?

I'll try to take a closeup picture.

Thanks,

Mark

To oxidize one of the base metals in the alloy you'd have to have both an acid component and an oxidizer, or both properties in one compound such as nitric or chromic acid. No such ingredients show on the MSDS and since the solution is organic (non-aqueous neither would have been compatible anyway. I suspect the smut might be from the loosening of old, dried motor oil or perhaps even from one of the rubber components. Or maybe something left in the chem-clean from a prior use? I'd just clean the parts thoroughly, perhaps give them a little wipe with 0000 steel wool, and go from there.

Perhaps it's just the vanished fuel breaking down, or previous paint on the pump.

Zinc carbonate is a protective layer and given the cleaner contains some alkalis that is probably what is being dissolved. Try the penny experiment.