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1948 DeSoto starts then sputters and loses power while driving but will not stall


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jharring10
New User

Aug 19, 2010, 8:33 AM

Post #1 of 6 (3095 views)
1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

 I used my 1948 DeSoto in a wedding for a family member. She ran flawless prior to 2008. The wedding was around 30 miles away and I hit some heavy traffic prior to hitting the highway so I pushed her pretty hard around 75mph to make it in time but she ran fine. After leaving the church, she started sputtering and loss of power once I got on the highway. She stayed running and I could rev her up when I pushed in the clutch (semi automatic) but never stalled. However, when I released the clutch she would bog down again. I luckily made it to the hall and the wedding was a success. I thought that the gas might be bad as this was her fight time out on the road that year. I filed her up, and then headed home after the event was over. I got on the highway and the same problem occurred. I then decided to take back roads with no issues driving under 40mph. I took her to the lake last Labor Day weekend via back roads (about a 1 1/2 ride). She was ok for about 30-45 minutes then she started to act up again. I topped her off at the next station and the problem did not improve, it may have even gotten a little worse but I did make it. I left her in the garage at my lake house for the long weekend. I headed back (after a few days) without gassing up at all (had almost a full tank) and the car ran perfect all the way home. This is my theory. I think that ethanol in the new gas may have cleaned or loosened any sludge in the tank after 60 plus years. When the vehicle was sitting for the weekend, any dirt has settled to the bottom of the tank but when I gassed up it stirred and disrupted all the junk in the tank. This fall I was going to drain out all the gas and replace the tank. Does this make sense? I would appreciate any feedback.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 19, 2010, 9:42 AM

Post #2 of 6 (3088 views)
Re: 1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

Hi,

I've had more troubles with ethanol in fuel as it keeps junk suspended. Don't know this engine'sl layout but probably has a glass sediment bowl you can see the junk. If so or it could be metal it should have a bail and dump out the junk and after that it's just a screen for larger degris. Dang ethenol is hard on some gasket material so a carb kit might be in order now and then.

Plenty to know. Floats should be brass and can get heavy or leak. There would be a spec for how much then should weigh.

More: Gas tank may have a drain plug! Wish they all did. If so just drain it and have something to catch that much. The dirt in there if any will come out usually with just that.

With low use you do need stabilizer for the fuel. Two types - one just keeps it stabil and another marketed by the Stabil Company claims to take out the ill effects of the ethanol. IDK but that's what it says.

Gelled gas if old enough sometimes will break up with a product called SeaFoam. Use stuff in moderation as I'm not a fan of magic in a bottle stuff too much.

I also suggest running engine dry of fuel if being left a while without much use. Put an in-line shut off so you can do that. Watch out and avoid using teflon tape for any sealing. If threads don't do it find something with just hose clamps.

Have issues with a 48 tractor and always run it dry and it love that. Harder to start of course but worth it.

Fuel is terrible today! If this sits a long time I'd be seeking out fuel from a Marina perhaps or an airport that doesn't use junk in the fuel. Haven't persued that yet but they can't always sell this junk gas for everything out there.

You can beat this. If nice dry storage I wouldn't leave the gas tank full like we always used to suggest and burn it out now and then for new.

I'd also think about adding a fuel filter for this with a popular part # that's large and can hold a lot,

T



jharring10
New User

Aug 20, 2010, 8:44 AM

Post #3 of 6 (3074 views)
Re: 1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

Tom,
You have provided some great suggestions. I do have a drain plug on the gas tank. I think that I will start with draining the tank, install a shut off and the biggest in line gas filter I can find before going to extremes like replacing the gas tank.

Jack Harrington
Nashua, NH


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 20, 2010, 9:25 AM

Post #4 of 6 (3071 views)
Re: 1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

Nashua! You are about 40 min from me in Marlborough, MA!

Just read a PDF which you can't copy about the ill effects of even 10% ethenol usually in small engines but at the age of this car it would apply. See if this link works to see the info from a popular small engine (and some larger) repair area of Robinson's Hardware.com, Hudson, MA............

http://www.robinsons1874.com/service/index.html

Just look around for the clickable file on effects of ethanol. It said they DON'T trust the Stabil brand as much as some marine grade fuel stabilizers!

It's my understanding that in NH if you are about 50 miles from an "X" populated city or town you can still get gas without the ethanol! Not sure if it's still true and I always fill up when up there as far as Jackson, NH.

If you do drain that gas I'd still use it but filter it thru a coffee filter or something real fine and use it in some non fussy something.

I don't have the filter part # on hand but just get a Ford fuel filter for an 88 Town Car - NAPA gold is best (wix filters really) and they are much larger and would fit in most rubber fuel line. Skip GM threaded ones and some of the junk for small engines - nice some are see thru but not good for a full size car.

Betcha this is the problem and can be solved with some thought here but might take cleaning some things too,

T



jharring10
New User

Aug 24, 2010, 8:27 PM

Post #5 of 6 (3027 views)
Re: 1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

Yes we are neighbors. I am going to try to use as little ethanol as possible. This car ran flawlessly until we were forced to use this crap. Last year I could buy non ethenol gas on the lake for my boat. This year they are offering ValvTect Marine Gasoline that is "specially formulated" for marine engines and is designed to prevent the problems of ethanol gasoline, such as phase separation, moisture, poor stability and the formation of power-robbing carbon deposits. So far so good. I found this web site that lists all non ethanol gas station by state. link deleted Meanwhile, I will drain my tank and start fresh. I have not found marine gas on land as I just may thry it. Can't be any worse than ethanol!


(This post was edited by Hammer Time on Aug 25, 2010, 2:43 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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Aug 25, 2010, 3:38 AM

Post #6 of 6 (3019 views)
Re: 1948 DeSoto starts then sputters and loses power while driving but will not stall Sign In

Been around here a while meaning New England. Amoco used to be the only gas stations that likely had a pump out back and called it "White Gas" meaning unleaded as well which was colorless and cheifly additive free specifically sold for Marine use but we always bought it for storage of seasonal items anyway. All that long before "unleaded" gasoline became the norm.

Gasoline we buy is only part pure product. IMO the additives are really just a way of selling the "gallon" but doesn't mean it's all gasoline! It's been weighed with as much as a pound difference when loaded with junk. Lead was a lie in hindsight too and was more of a problem than any help for you machine but you could use a lower chain of petroleum and get the same anti-knock effect of genuine higher octane gas. Just a cheap trick really. It takes a higher % of crude oil to make fuel behave to spec than diluting with cheaper additives.

If you use things all the time these additives don't matter much but many are the unstable part of fuel which if left alone is pretty darn stable!

So we buy additives to defeat additives - sounds smart to meCrazy Perhaps good intentions gone bad or plain greed.

It can still be solved. Seems for now #1 is not to store fuel too long. I've been marking the date on stored gas now for a while in an attempt to avoid the aggrevation.

Keep trying and please let us know what works the best as you know it,

Tom







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