Hawk not starting. I think fuel is not being pumped.

[lamelylounges]

Hi folks.

This is on my 88 blue hawk that had been sitting for 20 years in a garage.
I have cleaned the tank, replaced the petcock and replaced the fuel filter.
New fuel line running from gas tank to the fuel filter.
Cleaned the carbs very thoroughly.
Brand new battery.
Gas in tank (I put in probably 1/2 gallon of fresh gas).
Petcock turned to the reserve.

After putting it back together, I'm hitting the starter button and it cranks but I don't hear any combustion and I don't smell any fuel.
I need to do the obvious step of check if fuel will flow out of the petcock. If you could humor me and pretend we know fuel will flow from the petcock to the pump, I'd like to ask about this troubleshooting step below.

What and where is the "sub-fuse (10 A)"? I looked through my service manual and looked through the parts fiche and am having trouble finding this thing.
I think it's different from the fuel pump relay pictured below, right?

As long as I'm asking questions, what is the "Bu" wire color?
Bl must be blue.
Y must be yellow.



image.png​

Thanks!

[ParcNHawk]

Fuse panel is under the headlight.

Bl is black
Bu is blue
Br is brown

[bitzz]

Pull the fuel line off the carb and see if gas comes out.
The bike will run without a fuel pump if there is more than half a tank

[lamelylounges]

Thanks folks!

[yorkshire]

Hi, the fuses are under the headlight, the fuel pump fuse is number 6 marked as ignition, I believe the only fuse under the seat is on the starter relay, I do not know about sub fuse another than what I have said.

[6]

It has to crank for a good while before it will fill the carb bowls.

[lamelylounges]

Pull the fuel line off the carb and see if gas comes out.
The bike will run without a fuel pump if there is more than half a tank

I added more gas (tho maybe not quite up to a full 1/2 tank. Gas flows out freely when on reserve.

[lamelylounges]

Hi, the fuses are under the headlight, the fuel pump fuse is number 6 marked as ignition, I believe the only fuse under the seat is on the starter relay, I do not know about sub fuse another than what I have said.

I looked at the ignition fuse and it was fine. I should've looked at all of them while I was in there. DUH. But I was a bit rushed since it was lunch break.

[lamelylounges]

It has to crank for a good while before it will fill the carb bowls.

I have been letting it crank quite a bit, both last night and today at lunch.

[ParcNHawk]

I don't think the pump will let fuel flow freely through it. The valves will prevent that. If you remove it then the carbs will gravity feed with > ½ tank.


Also: jump the fuel pump relay to fill the carbs; don't do it by cranking it.

[rpcraft]

I have been letting it crank quite a bit, both last night and today at lunch.

A good while means like maybe 30 seconds, not 2 days...

if you want to test the fuel pump the best way is to disconnect it at or around the filterrs and dump it into a pan or fuel can. I can't recall what causes it to stop (time or pressure) but I know if you take it off and run some tube into a container it is far easier to tell

[squirrelman]

dija check for sparks

[Forcerouge]

It has to crank for a good while before it will fill the carb bowls.

To speed things up a bit, what I'm doing is to crank the engine and then block the carburettor intake with my hand for 1 or 2 seconds.
This creates a strong vacuum in the carburettor, sucking fuel almost instantly. It fills the carb right up.

Not sure if this is a recommended or proper way to do it, but it works very well for me.

[ParcNHawk]

So... you're filling the float bowl by using engine vacuum?

[Forcerouge]

So... you're filling the float bowl by using engine vacuum?

Essentially, yes.
Probably not the cleanest technique, I'm really no expert, but it worked well for me so far

Otherwise you have to either crank forever which isn't great for the starter motor, or you have to unscrew the little bowl screw and get fuel pouring all over the place, which are both techniques I'm not a big fan of.