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Discussion Starter · #1 ·
Hey, newbie here. Had my Shadow for a few years now and haven’t really had too many issues until I was getting busy and riding less. I left the bike for 2 months and couldn’t start it on return. I didn’t use any fuel stabilizer, plus the gas cap has a little leak when the tank is completely full… so probably lets more air in to ruin the fuel.
The battery is good, the engine cranks, and it even started for a little bit, but then couldn’t start again afterwards.

I figured that the carbs are bad, but before pulling them out and learning how to rebuild them, I wanted to try a few things. My goal was to get seafoam into the carbs and let it sit to clean them out. (I was going to try the following: https://www.youtube.com/watch?v=FonLaCVFMcU)

I first cleared out the old fuel from the fuel lines and tank and changed out the old fuel-filter. I noticed that the fuel pump did not seem to work, at least I couldn’t hear it working when the ignition was pressed. I followed this post (http://www.hondashadow.net/forum/72-technical-discussion/65947-bridging-fuel-pump-relay.html) to troubleshoot the fuel pump system. Either the fuel pump went bad, or the fuel pump relay did.



After cutting out the relay, it seemed like the pump was working. I disconnected the fuel lines before and after and had fuel pumping through with enough pressure to shoot out of the downstream line.

? One question I have here is, does the fuel pump shut-off if the carbs and fuel lines downstream are full and there is no space to pump gas into? When I had all the lines connected and full of gas, the fuel pump did not crank. Even when the float boat drain screws were open.

So to get the seafoam in, I wanted to drain the float bowls in the carbs along with the bad fuel left over in the connecting fuel lines.

I unscrewed both of the float bowl drain screws.



From the left side, only a few droplets of fuel came out. From the right ride, maybe one ounce of fuel came out. I thought there would be much more.

Using a funnel I poured in a bit of fuel directly into the fuel line connected to the float bowls (by passing the fuel filter and pump). With the float bowl drain screws open, I would have expected fuel to flow through. I even added some pressure to by blowing into the fuel line, but still no flow.

? How much pressure is needed to fill up the float bowls? I expect it isn’t much. I have seen that people run without fuel pumps and use gravity feeds to get the fuel in.

? So what could be the problem?
- Is there something I missed in trying to get gas / seafoam into the carbs? There is no other little fuel pump or valve somewhere just for the carbs is there?
- Could the fuel line be clogged somehow so that even a bit of fuel can't go through?
- Could the carb be so gunked up that I can’t even pour seafoam through?
- Is there something else I can try before taking out the carb?

Thanks in advance for any help!
 

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The gas cap doesnt leak, there is a vent to prevent you from overfilling it. In the 26k i owned my 2001, i NEVER heard the fuel pump.

Also, you never said if you checked spark, fuel is not even half of the whole equation.
 

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1983 Honda vt750 Shadow
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My thought also . Did you check for other systems working before ripping off the carbs?
If you spray a little carb spray into the carb throats or intake duct it should fire for a little bit if there is spark and compression, etc.
Don't forget the kill switch too.
 

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Discussion Starter · #4 ·
Could you guys comment on why no fuel would be pouring through with the float bowl drain screws open? How would someone get new fuel (or in this case seamfoam) in there?

Furball - The previous owner wrecked the bike and the gas tank had been redone. If I fill up the tank and slosh it from side to side, fuel leaks out of the top. I don't think it is the original gas cap.
I never heard the fuel pump either until I bypassed the relay, which lets it run without the engine cranking.
I did not check the spark pugs yet... my first step was to put new fuel in the system, which led to trying to drain the float bowls and run sea foam through them so that they would be in better shape.

Now that I did drain most of the fuel that was sitting in there, I am concerned that any other step won't help since there is not much fuel anywhere in the system. I am thinking that I already discovered the problem, since no fuel can move through the system.

Swifty - I didn't try out the other systems. My first step was to change out the old gas. Since I drained out the old gas, I thought I might as well get the seafoam in there to clean the carbs a bit.

I did buy some spray, which I want to try, but will it make sense without fuel in the system?

I appreciate any help or comments.
 

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Hi new guy!!! Welcome aboard!!! Sounds like the fuel system has got you in a bind. Now I don't know if the pump has a pressure cut off or not. I do know there are screens at the carbs fuel entry point. Then needle valves that are controlled by the floats. If all lines are clear then yes a few ounces should be all that is needed to see something pass through to the drains. A "trick" you can try is use a screw driver and tap the bowls a few times and then retest if fuel will pass into the carbs. If not try taking the fuels lines off and spaying carb cleaner in the inlets. If no progress from those atepmts, pull the carbs. Hope this helps. BE SURE TO USE EYE PROTECTION
 

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1983 Honda vt750 Shadow
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I put some Seafoam in an oil squirt can to shoot some into the carbs. You might try the same thing and pump it into the fuel line going into the carb bowl and see if you can clean the inlet screen and pop the needle open if it is stuck shut. With the drain screw out you should see the amount of fuel or Seafoam running out as you pump it in. At least you will be able to fill the float bowl to let it sit and clean inside.
 
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