water in gas tank

[plow_truck]

Hey,

I've been experiencing issues... I could get the engine to start. It would kicks over and then stall immediately, the carb clearly flooded (gas leaking out over the top).

Initially I was going to rebuild the carb (edelbrock 1406) but decided to replace it instead. I've never rebuilt a carb before so having a new one as a baseline to compare to seemed to justify the the expense. Anyway after a drop in replacement she ran fine, no issues. BUT a week later same condition.

I had been thinking of the possibilities and one that I came up with is water settling in the carburetor (see pictures of the air cleaner and carb... So I carefully extracted the "gasoline" out of the carb (mounted to the engine) into a glass jar to see what it looked like. It was clearly mostly water. Then it started right up and ran for a half hour.

In the pictures the jar of gas on the left came out of the carb. The one on the right came out of the tank AFTER running (still some water on the bottom).

Next day (after rain) it was hard to start again, though I was able to without pulling the top of the carb off.

I have a new sending unit on order. I am at this point thinking that replacement of the sending unit is in order anyway since the tube looks like its starting to rust though I suspect that the seal is probably the issue...

I've got mechanical fuel pump and do not think that the lines are the issue.

I have a plastic gas tank so corrosion of the tank is not a concern but I've never worked on this one so I don't know if the mounting of the sending unit is good. Worst case would be pull everything apart and then put a new gas tank on order...

Does anyone have any thoughts? Feel free to point me in the right direction if you think my assessment is wrong, all I'm after is getting the truck to start up reliably... Also, are these plastic tanks problematic or an improvement? Plastic tanks seem like a good idea but I guess I'll see what it looks like when I work on it.

Thanks

[Shifty]

First off, dump the tank, and clean as necessary.  Blow the lines out with shop air.  I would simply rebuild the carb, unless the water has destroyed the integrity of the metal.  Change the fuel filter, and possibly add a clear one inline as well.  Add a bottle of Heet (drygas), and see where you are.  If it dripped raw fuel/water into the engine, change oil as well.

[plow_truck]

agreed, step 1 is to empty the tank. I don't have a lot of storage capacity but it doesn't take much liquid and the tank is heavy and hard to handle. I'm just working in the driveway, I have no lift or anything like that which does make it harder than it would be (if I had a lift).

As far as the new carb, that is already done. Its waste on some respects but as someone whose never rebuilt a carb it just made sense... initially I thought that the linkages were not moving correctly and I needed a baseline of how the carb linkages should move and operate. Anyway the old carb will still be rebuilt, its small enough and with the box that the new came in I'll just hang on to it.

My fuel filter is a sintered bronze inline type right in front of the carb. I have cleaned this and yes of course will check it again.

All fuel lines will be checked.

I'll make sure to clean out the gas tank. I've been thinking of that for some time as I've been having these issues. In addition I want to make sure to do a good job to verify the seal between the tank and the sending unit. I'm not really sure what to expect with the connection probably I could have just ordered the seal kit, maybe I should leak check that before the replacement.

Anyway it looks like it should arrive sometime Saturday so it leaves Sunday to work on it, but that also means if anything comes up it'll wait until next weekend.

Oil change will be coming up soon either way.

[Shifty]

I find it a lot easier to just take the bed off (or tilt it back if you're working solo) to be able to get to everything. 

[plow_truck]

Taking the bed off would be the way to got but I got an old hemlock bed and the sander is still mounted.

Next year I'd like to put a dump body on.

I'm working to build a carport this year so even if I came across what I'm looking for its doubtful I could do the work (refurb the old dump body and swap everything out)... The carport will have chain hoist and trolley and this will be a huge help.

[Shifty]

Um, yeah....maybe not the bed...


 

[plow_truck]

I plugged the breather line then pressurized with a bike pump connected to the 3/8 fuel line. I applied soapy solution around the sending unit and sure enough there were bubbles. So the sending unit was failing at the seal.

The old gasket is a square section gasket and seems to have been installed with RTV. In addition the lock ring gets clamped down with dogs made out of 0.060 thk strip steel using sheet metal screws. There are bosses internally and the screws don't poke though the wall but I have approximately zero faith that I can get a good seal that'll last the winter.

I'm going to buy a new tank... and possibly filler neck too.

Here are some pictures. At present the fuel and breather lines are plugged, the old tank is not installed.

[JohnnyPopper]

Good catch!

We sure love us some pictures-Thanks!

[plow_truck]

so the new steel tank came and I was able to install it over the weekend. I ended up getting the "spectra Premium" GM1B steel tank. Note that this was under the 1984 model year. After a bit of searching it seems that 1979-80 use a 1.38 od filler neck  on the tank and the later years use a 1.75 od filler neck. Since my truck is a flatbed and since the connection to the tank was pretty rough I replaced this rubber, the clamps and hardware too.

Anyway putting the new tank on isn't so bad. It took a while and when I was under there I became aware that exhaust hangers were broken so I replaced 4x exhaust hangers too...

Its too bad that the tank cannot be drained completely without removal. What I'm thinking is that if the seal ring fails again you really need to drop the tank to clean it thoroughly since the most the sending unit will pump out leaves about a gallon in the tank. Of course all the water is at the bottom so need to make sure you get rid of this.

Prior to running the engine:
I put 6 gallons of gas in the tank.
I made sure to clean out the carb with the same process as earlier and it was again full of water.
I cleaned out the gas lines by disconnecting the fuel line from the carb and putting it into a gas can, then turning the motor for about 15 seconds.

Once the fuel line was reconnected she started right up and ran fine. Sadly the radiator sprung a leak when she was idling... so thats next up.

[bd]

Coming along nicely!