Boiling Gas in tank.

[Panhandlewillie]

I have been having an issue with the gas in my fuel tank coming to a rolling boil when my tractor gets hot. I have to run with the cap loose and it hisses. Opening the tank scares me. I keep waiting for a fire. Has anyone had trouble like this and how do I remedy it?
Thanks, Brett

 

[john_Bud]

First off --> STOP USING IT !!

Next, you probably have a faulty heat shield between the exhaust and the fuel tank. They rust and rot fairly easily. You will need to undo the sheet metal and tip it forward (it pivots), then remove the tank and if you can find one - replace the shield. If not, you can bolt or pop rivit a new shield in place.

If you can find some mineral wool (not fiberglass!) put that in a sandwich under the tank for better insulation.

Your exact symptoms are what thousands of people told the fire department after the fire was out -- if they lived. Gas boiling is a huge bomb waiting for an excuse to go off with either a fire ball or a ka-boom. Don't mess around, get it fixed.

jb

 

[jimNCal]

AS JOHN SAID----------STOP USING IT!!!

Liquid gasoline isn't a problem......VAPORS EXPLODE.

I have a used/ (somewhat abused) heat shield I'LL GIVE YOU for the cost of shipping it to you IF, IF you'll STOP USING that tractor until you get this PROBLEM FIXED!!!

jim

 

[Dell (WA)]

Brett......modern no-lead gas seems to be more willing to "boil" than real gas. Butt just the same, yer "heat-shield under yer gastank ain't working. Missing??? More insulation needed??? Think coal stove ceramic insulation in a buckett. Its "water-proof". Also think NEW breather gas-cap 'cuz yer tank vent is probably plugged by mudd-daubers. ......Dell

 

[Dean]

Brett:

Assuming that you are speaking of a 9/2/8N, there is no heatshield between the engine and the fuel tank. If you are speaking of another Ford, model years 1953-1964, there is a heat shield between the muffler and fuel tank, which must be in place and functional.

IF you can find gasoline without ethanol and use it, the boiling gasoline problem will vanish.

 

[Panhandlewillie]

It"s a 600 with a 172in 800 engine & petronix ignition.
Does anyone have a pic of the heat shield so I can verify if I have one?

Thanks, Brett

 

[Dell (WA)]

Brett.......the 172 engine ain't the issue, ittz'chur HEATSHIELD ain't shielding. What do you think a heat-shield looks like that you need a picture??? Think cookie sheet about 1/2" away from bottom of gastank. They're NOT as robust as they should be and often times have "rusted and melted" and thrown away. Its NOT rocket science. sheesh ....... respectfully, Dell

 

[JMOR]

 

[Blindhawg]

I speak from experience. Never open that gas cap when the tractor is hot! I have a brand new tank and cap (which was unvented) One day after bush hogging the heavy stuff, I popped the cap after shut down and experienced a geyser of gas! I was lucky, no fire.
Trust me, even with a perfectly good shield, you"re still going to get a lot of heat build up under that hood. It"s just a bad design. I"m not knocking the old tractors, but 11 gals of gasoline underneath the hood and on top of a hot engine???? Just like any tool,know they can hurt you and be safe.

 

[Anonymous-0]

Boiling gas dosent have to ignite to burn your hands and face.

 

[Anonymous-0]

Buy a vented gas cap from CNH dealer.The free exchange program may still be good.Bring your serial number to the dealer..DO NOT OPEN THE GAS CAP ON A HOT ENGINE.

 

[Dave in MS]

When I bought my 640 it was a basket case with a few missing baskets. I made a heat shield from some 1/8" aluminum sheet that had been a road sign in a previous life, and cost a dollar at a local scrap yard. I had nothing to look at for a pattern, but it wasn't difficult to take some measurements and transfer bolt hole locations to the sheet. I made a cardboard template and kept trimming it until it fit, then drew around it on the aluminum with a sharpie, and cut it out with a jigsaw. If you go this route, make two sheets, and bolt them together with 1/4 inch bolts with 4 or 5 washers between the sheets to give you an air gap. When you drill the mounting holes, make the holes in the lower sheet big enough to let a 7/16 socket pass through . If you are going to show the tractor get a stock shield.. If you're going to work it, the aluninum shield will keep it cool, and it will never rust. The fan blows cool air through the gap between the sheets, and I have yet to run hot, including last week in 100+ degree weather

 

[Dave in MS]

This is what the finished product lookes like:
Under side view of clearance holes in lower part.