How do I re-condition a Johnson Mile Master 6 gal fuel tank circa 1968?

[Mr. Matt]

Greetings,
I purchased a 1968 Johnson 10 HP motor circa 1968 with the tank and I would like to take a shot at reconditioning the engine. I drained the gas out of the tank, but it has 10 years of crud on the bottom. I have watched videos on how to clean the tank and was considering the "cement mixer" solution, but that would destroy the float, fuel line, etc inside the tank. Is there a best practices way to clean out the rust and sludge in the tank? Pea gravel and then shaking for an hour may work, but it is a big tank...
!

 

[racerone]

Remove the gas line // gauge / fitting etc.-----Just 4 screws and it comes off.----Remove the 2 plugs and replace O-rings on the valves.

 

[F_R]

You might ask yourself if it is worth the effort. It's not like they are rare or anything.

 

[boobie]

What's the cost of a new tank ??

 

[F_R]

A quick look found several on e-bay starting at around $40-ish (used)

 

[Mr. Matt]

Time is money, that is for sure. If I clean it myself, then I know what I will have, though, when done. If I buy a used tank w/ shipping, I may get one that needs as much attention as the one I have. Once the gauge/float assembly are removed, is there a best way to clean out the interior?

 

[oldboat1]

Yes. You have some access to the interior to scrape at the rust, varnish, etc. In combination with a solvent or two, it can probably be brought back. Decals are available. Get a plastic tank for working on the engine in the meantime.

 

[F_R]

You probably will find that the entire interior is rusted. First you have to make some sort of a plate to cover the hole where you took the gauge assembly off. Then dump in a bottle of isopropyl (rubbing) alcohol and a couple handsfull of nuts & bolts, or whatever else you have on hand. Then shake it till your arms fall off. Keep turning the tank to let the nuts bang against all interior surfaces. Repeat. Repeat. Repeat. Keep it up till you give up, then check inside to see what progress you have. Eventually, it will come reasonably clean.

BUT, just like a rusty old tin can, it will rust again. The tern plating is gone. In the meantime, you will need a good fuel filter to strain the remaining rust dust out of the fuel before it fouls your carburetor.

Been there and done that. More times than I care to remember.

 

[jimmbo]

That crud you are referring to, is it rust, or just old fuel that dry up and left a bunch of oil varnish and gum, mostly on the bottom? If the tank is relatively free of rust, I would remove the float/gauge/fuel pickup, get a gallon of Lacquer Thinner, and put about 1/4 of it in the tank and let it sit for a while, agitate it, let it sit. After several hours/days drain it and repeat. Don't use plastic pails for the waste.

Of course the coat of a gallon of Lacquer Thinner is probably about 1/4 - 1/3 the cost of a new tank... A new tank is a sure thing for the money spent. Trying to clean a tank might be equal to throwing the money in a campfire

 

[Rustywrench]

IF you find one with gum & varnish ammonia works well at almost no cost? $1.00 for a gallon at any Dollar General. Yeah it stinks & nobody thinks about it anymore, but it works on varnish & gum. Rinse well as it will rush the steel. Oil well or put your premix in. Still a filter is a good idea as small bits get by.

 

[Mr. Matt]

Thanks to all for your answers and suggestions, sorry for the slow reply. This is rust and sludge from letting the tank set in an unheated space, with gas in it, for a decade or so. I pulled the gauge and have cleaned that. The tank has rust accumulation on top and side, not so much the bottom, though. Cleaned the loose stuff with a beveled hardwood scrap and shook gravel in the tank for about 10 minutes. Then, called a buddy to borrow his cement mixer. I'll strap the tank to the top, dump in washed gravel and seal the opening. Then, run for an hour or so. I'm told that it works wonders!

I'll wash the tank out with gas and then, I'd like to seal it. Any other suggestions for sealing the tank would be appreciated.

 

[alanfox55]

Lots of stuff on YouTube about cleaning a steel tank. Most of what I've seen involves filling the tank with vinegar and letting it sit for a week.

 

[Mr. Matt]

I ran the tank strapped to a cement mixer for 2-3 hours, changing out the gravel 2-3 times. I then ran it with about three lbs of loose metal scraps, bolts, nuts, etc that I had been saving foe recycling. It did a pretty good job of scouring the inside of the tank. I will start a new thread concerning installing the gasket kit.

 

[Mr. Matt]

Mile Master 6 gallon tank cleaned for service, installing gasket kit?

I ordered the Mile Master kit from Laings in N. Tonawanda. I carefully dis-assembled the tank assembly and gave it a good cleaning. I installed all the items in the re-build kit, with the exception of the fuel line o-rings and two neo-preen washers. I used eight of ten to attache the tank handle assembly back to the main tank body, why did the kit include 2 xtra?

Also, is there a trick to replacing the 0-rings? I watched one video where the person doing the job had a nifty tool for banging out the o-ring assembly from the fuel line housing, but it is probably 20-30 buck

 

[GA_Boater]

Lets keep this all in one thread since all the posts are about reconditioning the tank, including gaskets and o-rings.

Got a link for the o-ring video?

Since you had rust inside, a pressure test is always a good idea in case of pin holes.

 

[Mr. Matt]

Sure, OK, here is a link to the video:

https://www.youtube.com/watch?v=JsSTUknjg48

I was going to attempt with the tools he had on the clean work area, but, what do I know.

 

[GA_Boater]

You could use a thin-wall socket to to catch the brass thing and to tap it back in instead of the fixture.

 

[Mr. Matt]

I'm worried about scoring the brass part while taking apart or damaging some other internal part. Maybe, I worry too much.

 

[GA_Boater]

Yes, you worry. :smile:

The only face to worry about is the large side knocked into the fixture to take it apart. He tapped on the that face to reassemble. No internal parts to damage.

You only tap, not beat it to death with a BFH.

 

[Mr. Matt]

Thanks, I'll leave the "farm boss" in the tool kit and take it nice and easy. Tap-tat-tappie....