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A lesson in dirty old fuel tanks

KT3survivor

Active member
Like many Kristi's still alive out there, mine has spent a large portion of its life sitting still and because of this, the fuel tank has suffered. Here are some of my discoveries that could possibly help someone else out someday. But I will tell you, dont trust the work of the previous owner or it will bite you in the ass.

when I took ownership the engine started and ran, seemed to be in decent running order. then I let the machine sit for another 7-8 years. when I finnally got around to working on it It had a siezed up cylinder and a couple bent pushrods.


it also had a very clogged oil strainer,

indicating that the last time it ran it was sucking dirt and rust thru the sump.
so I cleaned, measured and rebuilt. during this time i was told by one of the two previous owners that the other owner/operator removed and flushed the tank. one less thing to do I thought . . . . I'll just flush it out with fresh gas. . .

then I broke in my rebuilt engine. all was well untill i tried to start it (cold) for the second time, resulting in a couple more bent push rods. one intake valve was completely stuck closed and another was stiff. pulled the engine back apart and found this on the stuck valve

hard to see but imagine using molasses instead of assembly lube and you will get the idea. solvent was useless against it. had to use acetone but once clean, the clearance measured good.

everything pointed to the old smelly tank so i removed it and found this


here is the last bit of fuel after settling


so i have spent the last couple days sloshing acetone and a chain around inside the old tank. still getting this red gunk out after 4 rounds.


what do you guys think of this crap? is it a failed tank liner kit by a previous owner? did kristi coat the insides somehow?? anyway, my por-15 kit literally just showed up at my doorstep but i think i need a few more rounds of acetone. . . what do you guys think?




so the red shit looked like dried paint before i used acetone on it. but the grey seemed like alot of fine sediment and sand that was very similar to what was inside the siezed cylinder and oil strainer. starting to think the two are related.

any comments on my forensic analysis??
 

PJL

Well-known member
My guess would be rust and material flaking off of the inside of the tank. Looks to be a horrid mess to fix.
 

snowcatt

Member
hi
My Bombardier tank had the same lining in it .
i bought a gallon of muriatic acid at home depot
i dumped it in let it sit and kept turning the tank it all came off .
then i lined it with 3M sloshing compound
seem fine
good luck
 

Track Addict

Bronze Member
GOLD Site Supporter
Sounds like a good time to replace the tank. Plastics can be had pretty cheap and in many sizes.

Had no luck with kreme or sealant as a long term sometimes.
 

KT3survivor

Active member
thats good to know about the muratic acid, and its cheaper than acetone so I'll give that a try for sure. as much as I'd like to replace, I would end up building a new steel or aluminium one from scratch since it supports the front and rear bench seat and fits inside a tight spot in the frame. but sadly I dont really have a budget for that so, liner it is. I did a por15 kit on my datsun 10 years ago and its doing just fine. hopefully I will have the same luck here.
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
if you are using por 15 the acid bath is unnecessary the as the por 15 kit comes with a catylizing rest converter you apply first the item only needs to be degreased. por stands for paint over rust
 

Cidertom

Chionophile
GOLD Site Supporter
feel for you. I had similar, the old lining in the tank was coming off in shreds and it had about 3/4 inch of solid varnish on the bottom. Acetone didn't cut the old lining very well, I wound up using MEK, which I hate as it's nasty stuff. I was saved I think by having two inline filters.
 

KT3survivor

Active member
if you are using por 15 the acid bath is unnecessary the as the por 15 kit comes with a catylizing rest converter you apply first the item only needs to be degreased. por stands for paint over rust

I agree. But any other debris must be removed and this crap is more than just rust. comes out by the handfull, when you can get it out and i can still see edges of it. im not as worried about the rusty sides and top, just the layer im still cutting thru on bottom is the concern.


feel for you. I had similar, the old lining in the tank was coming off in shreds and it had about 3/4 inch of solid varnish on the bottom. Acetone didn't cut the old lining very well, I wound up using MEK, which I hate as it's nasty stuff. I was saved I think by having two inline filters.

that sounds pretty similar to what this started like. but sounds like yours was thicker. mine also had 2 filters so i plan on cutting them open just to see what was getting thru.
 

KT3survivor

Active member
hi
My Bombardier tank had the same lining in it .
i bought a gallon of muriatic acid at home depot
i dumped it in let it sit and kept turning the tank it all came off .
then i lined it with 3M sloshing compound
seem fine
good luck

this is legit. thanks again man!!


overnight soak & slosh and it should be clean enough for a liner
 
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