No start after gas tank flush

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SLOdatsun
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No start after gas tank flush

Post by SLOdatsun » Wed Mar 13, 2019 12:39 pm

Hey all!
1967.5 1600 with new water pump, thermostat, fuel filter, headers, shorty starter, rebuilt alternator.

Wanted to let you know that I looked through posts for hours before writing, so I appreciate the personalized help...in advance!

My gas tank had so much sediment it made my fuel filter look like a cement mixer after 20 miles of driving so I dropped the tank and had it boiled at a local shop. I used my air compressor to blow out any sediment from the filter line back to the (not present) tank. Reinstalled the tank, hooked up the lines to the tank, replaced the filter, then put in new fuel. I can see gas bubbling in the glass but the car won't start, even after shooting starting fluid thinking that maybe it needed to run a little to get everything cycling.

Bear with me, I'm teaching myself car repair and maintenance so *fingers crossed* I'm missing something glaringly obvious. If not, what would be a good easiest-to-most-invasive strategy for finding the issue?

Again, thanks in advance for the help.
'67.5 1600 w SU carb, Spanish Red
1st time "restorer"
Central Coast, CA

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mraitch
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Re: No start after gas tank flush

Post by mraitch » Wed Mar 13, 2019 2:04 pm

check that there is fuel in float chambers - perhaps some starting fluid??
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notoptoy
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Re: No start after gas tank flush

Post by notoptoy » Wed Mar 13, 2019 2:20 pm

Bubbling at the fuel filter sounds like an air leak to me. Check and replace any rubber hoses, and most importantly check the gasket on the glass filter fuel bowl. They tend to dry out and let air by. A light smear of grease on both sides of the cork gasket may be enough to seal it back up. As Peter says, check for fuel in the float chambers and try some starting fluid.
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Linda
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Re: No start after gas tank flush

Post by Linda » Wed Mar 13, 2019 2:24 pm

You may go thru many fuel filters despite the tank clean out. I did after having the tank professionally cleaned. Maybe try another filter after trying everything else.
You might have to prime the fuel bowls to get the carbs going too, then be sure they are sealed well.
Good luck !
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GeoffM
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Re: No start after gas tank flush

Post by GeoffM » Wed Mar 13, 2019 3:34 pm

Its probably that the fuel line needs to be primed so it takes a long time for the pump to suck fuel from the tank all the way to the pump. The air in the filter may be the air being displaced by the fuel as the pump draws it towards the engine. You may have to crank it for a while.
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spags1986
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Re: No start after gas tank flush

Post by spags1986 » Wed Mar 13, 2019 3:46 pm

I agree with notoptoy and in fact had the same experience. My glass bowl started leaking and ended up just ditching it for an inline. At the time I wasn't aware people make rebuild kits for them but I am thinking this is the root of your problem.
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Re: No start after gas tank flush

Post by C.Costine » Wed Mar 13, 2019 5:37 pm

Blowing out with air can leave way more than enough crud to plug the line. I would flush it backwards with a quart or two of mineral spirits followed with a little acetone. You don't mention the pump. The OEM pump has little valves that can get hung up by crud. Depending on what type of pump it is, once you have the clean gas going to it, disconnect the discharge and verify that it is pumping as it should.
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fj20spl311
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Re: No start after gas tank flush

Post by fj20spl311 » Wed Mar 13, 2019 8:38 pm

Its not the fuel if it wont start with starting fluid!!!!!

Check your spark and voltage to the coil.

You need three things to run....spark, fuel and air. Air is almost never the problem.
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Linda
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Re: No start after gas tank flush

Post by Linda » Wed Mar 13, 2019 10:31 pm

Don't you have to spray and crank at the same time, and right into both carbs? If so, that seems hard to do by yourself.
I don't think I have ever used starting fluid lol
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jrusso07
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Re: No start after gas tank flush

Post by jrusso07 » Thu Mar 14, 2019 7:09 am

If you accessed the fuel line at the hard line, down by the frame, you may have inadvertently knocked the wire off the distributor or resistor as they are in close proximity.

if you think it is fuel related, you can disconnect the output side of the fuel pump and run it (fuel) into a containr. There are specs on pump rate. You can disconnect the fuel line at the carb input.

Here ard specs on pump viewtopic.php?t=29404


The stock pump uses a rubber diaphragm - if it ruptures or is torn, it will suck air. There is a weep hole on the underside of the pump. See if it is wet from fuel leaking out. Use a paper towl or cleandry rag.if it is wet, you nee ed to rebuid or replace the pump.
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redroadster
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Re: No start after gas tank flush

Post by redroadster » Thu Mar 14, 2019 8:55 am

Use Flamable carb spray .... not starting fluid
unless its 0 to -30 degrees its only use

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Gregs672000
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Re: No start after gas tank flush

Post by Gregs672000 » Thu Mar 14, 2019 10:30 am

fj20spl311 wrote:
Wed Mar 13, 2019 8:38 pm
Its not the fuel if it wont start with starting fluid!!!!!

Check your spark and voltage to the coil.

You need three things to run....spark, fuel and air. Air is almost never the problem.
My first thought as well... pull a plug or coil wire and confirm spark first, should fire on starting fluid. Don't soak it, just a quick shot.
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redroadster
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Re: No start after gas tank flush

Post by redroadster » Thu Mar 14, 2019 4:13 pm

Gregs672000 wrote:
Thu Mar 14, 2019 10:30 am
fj20spl311 wrote:
Wed Mar 13, 2019 8:38 pm
Its not the fuel if it wont start with starting fluid!!!!!

Check your spark and voltage to the coil.

You need three things to run....spark, fuel and air. Air is almost never the problem.
My first thought as well... pull a plug or coil wire and confirm spark first, should fire on starting fluid. Don't soak it, just a quick shot.
fire and break a ring land ! you know a 50 yr old one . you can do the same thing with carb spray ,just retard the timing severely so the the power hits at near TDC or before causing a sever buck ...but why would you want to do that... gas in a mustard squirt bottle is my choice .
when a car came in to the datsun shop and had staring fluid in the back or you could smell it in the engine , they blew it out the door ...no thanks

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Re: No start after gas tank flush

Post by SLOdatsun » Thu Mar 14, 2019 5:32 pm

Thanks all. I'm going down the list and trying my hand at all your suggestions, but I found a solution (kind of) right away by adding fuel in the float chamber. It started immediately and ran...until the float fuel ran out.

I re-seated the glass/gasket/filter to make sure that was good and there's no bubbling in the glass, but it looks like the fuel is just staying there. I visually inspected the hard lines, and already replaced the rubber fuel hose from the filter to the pump, then I took the top off the pump for a visual inspection and the metal screen was clean. The whole thing looks brand new.

Before I dig deeper tomorrow, can I get an opinion on what I might check next?

Very thankful for all your suggestions so far.
'67.5 1600 w SU carb, Spanish Red
1st time "restorer"
Central Coast, CA

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Linda
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Re: No start after gas tank flush

Post by Linda » Thu Mar 14, 2019 6:09 pm

There are float valves inside the fuel bowl lid. They can get stuck or be worn and either not seat or get stuck. Try carb spray first. Also there is a little filter inside at each intake, which can also get plugged. Check a car diagram to see these parts.
Glad it ran!
You might not be pumping gas from a shot fuel pump as explained, so check the outflow.
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