gas under pressure

[andydap]

hi everyone, just got a massey ferguson 165 with a perkins gasoline engine. went to check the gas tank after using it awhile and the cap exploded off the tank. on closer reading the cap it said, open slowly. why and is it necessary to have the tank under pressure? can't i just use a normal cap. this tractor uses a lot of gas.
thanks,
andy

 

[M-MAN]

Sounds to me like the gas cap vent is stopped up. I would replace it with a new vented cap. There's also the possibility you should have a heat shield and it's missing.

 

[EFV]

hi everyone, just got a massey ferguson 165 with a perkins gasoline engine. went to check the gas tank after using it awhile and the cap exploded off the tank. on closer reading the cap it said, open slowly. why and is it necessary to have the tank under pressure? can't i just use a normal cap. this tractor uses a lot of gas.
thanks,
andy

It's not necessary it's very dangerous. Very likely you can get a vented gas cap for free. IH didn't build tractors with vented caps
and that's why you can still get a free vented replacement. As you noted the pressure would force gas and vapor out with force
often igniting and causing incredible harm. If your cap is vented clean or replace it. Burn units are horrible places to visit and
burn injuries can be painful forever.

 

[Jim.ME]

It is supposed to be a vented cap. I have seen aftermarket vented caps with such a warning on them. They might be putting the warning on all caps vented and non-vented (manufacturer's CYA). I believe the warning is a caution to avoid a fuel spray if the vent plugs as it appears is happening with yours.

 

[urbancase]

Agree that should be vented, I know my 65 and 135 are.

 

[used red MN]

We had a Farmall 656 gas on are farm as the big tractor in the 70’s. Unlike the older Farmalls that had their gas tank completely behind the engine on this tractor the tank became shallower and extended roughly a 1/3 to 1/2 the way over the top of the engine. Even though the vented cap was open and venting as designed on hot Kansas days a steady flow of vapor would blow out of the vent hole. It didn’t take you long to figure out that if you didn’t “open it slowly” so the pressure would vent off you would probably be hopping off the tractor to retrieve the cap because it got blown out of you hand. I often wondered how many GPH (probably more like pints) actually just evaporated out of the tank on those days.
If you determine there is at least some type of venting in your cap what you experienced is probably normal.

 

[BarnyardEngineering]

https://www.yesterdaystractors.com/Massey-Ferguson-165_Fuel-Cap-Vented_184806.html

 

[John M]

It's not necessary it's very dangerous. Very likely you can get a vented gas cap for free. IH didn't build tractors with vented caps
and that's why you can still get a free vented replacement. As you noted the pressure would force gas and vapor out with force
often igniting and causing incredible harm. If your cap is vented clean or replace it. Burn units are horrible places to visit and
burn injuries can be painful forever.

Not accurate. IH caps had 1 vent hole, that would get blocked by rust, dirt, etc. An accident occurred, IH was sued and lost and came out with the 2 vent hole cap as a replacement and gives it away for IH tractors. The program continues today through whichever company owns them this week.

 

[EFV]

Not accurate. IH caps had 1 vent hole, that would get blocked by rust, dirt, etc. An accident occurred, IH was sued and lost and came out with the 2 vent hole cap as a replacement and gives it away for IH tractors. The program continues today through whichever company owns them this week.

I stand corrected. One of the presenters at the last Red Power Roundup said there were
multiple accidents. An aside to this is that when John Deere was developing the New Gen
tractors the fuel tank was absolutely and positively going to be at the front of the tractor
and NOT over the engine for safety reasons.

 

[andydap]

hi everyone, thanks for your comments. i did replace the cap with a known vented one and not only did it not explode but i also used half the gas i did before.