Topping off Tank?

This is the place to get help with technical matters concerning your M151 jeep

Moderators: rickf, raymond, Mr. Recovery

Post Reply
User avatar
Surveyor
Terminal
Posts: 1092
Joined: November 13th, 2015, 3:56 pm
Location: Cajun Country

Topping off Tank?

Unread post by Surveyor » October 16th, 2019, 10:28 pm

Tried a search first but no luck. Pre-emission tank. How fast should one be able to fill the fuel tank to the top lip? The problem I've noticed is that the tank appears to fill to the top lip but then slowly draws down the neck after a few minutes. I assume the tank is filling up to the bottom of the neck. Once it gets above there the air inside is trapped and is slowly venting out the vent line as I fill the neck over and over??? Should it vent fast or is this normal? Just doesn't seem right to me that it would take so long. I'd like to keep it close to the top for the upcoming winter due to the huge temp swings we get sometimes.
1960 M151 Run #1
"There is one nut on a M151 that is very difficult to remove....." - K8icu
"She ain't a Cadillac and she ain't a Rolls, But there ain't nothin' wrong with the radio" - Aaron Tippin
Image

Mark
Brigadier General
Brigadier General
Posts: 2085
Joined: September 19th, 2009, 11:33 pm
Location: South Dakota

Re: Topping off Tank?

Unread post by Mark » October 16th, 2019, 11:29 pm

When I fill the tank, I have the nozzle pointed at the bottom of the spout/hole.It fills up quick, I'll time it next time
mark


1968 m274A5
1960 m151
1981 m151A2
1964 m416
1971 m416

Hambone
Brigadier General
Brigadier General
Posts: 2495
Joined: October 1st, 2010, 12:19 am
Location: El Dorado, Arkansas

Re: Topping off Tank?

Unread post by Hambone » October 17th, 2019, 7:39 am

Sounds like air pocket, definitely keep that tank full.

User avatar
muttguru
Colonel
Colonel
Posts: 1992
Joined: November 26th, 2007, 12:18 pm
Location: Li'l ol' England.....

Re: Topping off Tank?

Unread post by muttguru » October 17th, 2019, 1:53 pm

Here's an interesting picture. The actual marking is not "by-the-TM" but nevertheless is good advice. Whether your mutt is in SG-OD or camo, you should have the vehicle marked "Caution. Do not overfill. Allow for expansion".
I understand your reason for wanting to fill 'er up but it's it is best not to overdo it :D

Ken


Image
Kind regards....
Ken

Always wanted - Details and pictures of M416 Trailer data plates & M151 data plates & body-tags for my research. Thanks!

Contact address - - muttguru@aol.com

Note for 2023..... Ken..."Less Stress - More Exercise!"

User avatar
m3a1
Lt. General
Lt. General
Posts: 4029
Joined: August 7th, 2014, 6:36 pm

Re: Topping off Tank?

Unread post by m3a1 » October 18th, 2019, 10:59 am

As has already been mentioned, don't fill your truck's fuel tank to the top. Long experience lead the military to paint a very noticeable warning label below the filler of every tank. If you are feeling that you need to have that extra fuel on board, get a fuel can in good condition and carry it where it belongs, securely strapped in, over the left bumperette.

Obviously there is more to just having the can of extra fuel. Don't forget having a filler neck for that can...one that is clean and in good condition and stowed so that it is not underfoot. Q - Why is a fuel tank like a computer? A - Garbage in, garbage out!

Also, if you elect to use the inexpensive Chinese-made fuel cans for this purpose (or any can for that matter) consider protecting the bottom of that can by slicing a section of fuel hose lengthwise and fitting it over the top of the bumperette to serve as a cushion between the bottom of the can and the top of the bumperette. Constant vibration where two unprotected pieces of metal rest against one another never has good results.

Cheers,
TJ

User avatar
rickf
General
General
Posts: 19741
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Topping off Tank?

Unread post by rickf » October 18th, 2019, 4:54 pm

The reason they are wanting to top it off is for winter storage. The less air the less chance of moisture in the tank from temperature changes pulling it in. With moisture you get phase separation.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
m3a1
Lt. General
Lt. General
Posts: 4029
Joined: August 7th, 2014, 6:36 pm

Re: Topping off Tank?

Unread post by m3a1 » October 19th, 2019, 12:25 am

Ahhh... I get it.

Post Reply