RobSelina
Jedi Warrior
Offline
Okay, my HS4 leaks fuel into the intake. That's what's causing it to run rough. Last time I took the carb off and found fuel in the intake, I assumed it was because the piston wasn't traveling freely. I took the carb apart and cleaned the damper well. There was some grit in the chamber.
Pulled the carb this morning after I could not get it to run consistently last night. Here's a description of the details I've noticed:
* Standing fuel in the intake. Roughly 1/16"
* There was no fuel pressure on the fuel line. Note that during testing last night, after firing up the pump and then cycling the ignition off, there was good fuel pressure when I pulled that line. I'm relatively confident the float/intake valve are operating correctly
* The float bowl was nearly empty. Even if the foat was malfunctioning, this wouldn't explain why the fuel leaked into the intake right?
* This time, everything is sparking clean. The damper comes down with an authoritive thud when lifted. The rate at which it falls and the resistance it presents when lifted, all seem appropriate.
* The needle isn't straight on the piston. It's spring loaded and offset slightly to the engine side. After reading the Haynes SU manual, this apears to be a design feature. There's a slight dimple in the metal piece that holds the needle to the piston.
* The jet is clean and shows no signs of irregular wear. I had previously blown carb cleaner through it to remove any sediment. I don't really know how to inspect a jet or needle, but the needle seems straight and does not have any visible scaring, neither does the jet.
* During reassembly last time, I only applied WD40 on the exterior of the jet to allow it to move up and down. I gather I should have used petroleum jelly according to the manual. I don't think this explains why the fuel was leaking but I mention it for completeness.
I'll also mention I'm using a Facet electrical fuel pump with no external regulator. Although I've always had a positive impression from this pumps operation, I'm reading some nasty stuff about it on google. Could my fuel pump pressure be to high?
The float presntly sits at a 20-degree angle to the carb body, I'm planning on grinding down the grommet so it sits level & rotating the float so it actuates front to rear, not left or right.
Related question - when the manual says to oil something, what am I suppsed to use as oil? motor oil? I'm planning on putting a little wheelbearing grease on the throttle shaft and exterior of the jet (where it slides inside the housing). On the piston/dome, I'm planning on using a little motor oil on the housing, just to provide light lubrication.
This one has me stumped. How/why is this thing leaking? could I just have the jet adjusted too low so it doesn't close against the piston?
Thanks!
Rob
Pulled the carb this morning after I could not get it to run consistently last night. Here's a description of the details I've noticed:
* Standing fuel in the intake. Roughly 1/16"
* There was no fuel pressure on the fuel line. Note that during testing last night, after firing up the pump and then cycling the ignition off, there was good fuel pressure when I pulled that line. I'm relatively confident the float/intake valve are operating correctly
* The float bowl was nearly empty. Even if the foat was malfunctioning, this wouldn't explain why the fuel leaked into the intake right?
* This time, everything is sparking clean. The damper comes down with an authoritive thud when lifted. The rate at which it falls and the resistance it presents when lifted, all seem appropriate.
* The needle isn't straight on the piston. It's spring loaded and offset slightly to the engine side. After reading the Haynes SU manual, this apears to be a design feature. There's a slight dimple in the metal piece that holds the needle to the piston.
* The jet is clean and shows no signs of irregular wear. I had previously blown carb cleaner through it to remove any sediment. I don't really know how to inspect a jet or needle, but the needle seems straight and does not have any visible scaring, neither does the jet.
* During reassembly last time, I only applied WD40 on the exterior of the jet to allow it to move up and down. I gather I should have used petroleum jelly according to the manual. I don't think this explains why the fuel was leaking but I mention it for completeness.
I'll also mention I'm using a Facet electrical fuel pump with no external regulator. Although I've always had a positive impression from this pumps operation, I'm reading some nasty stuff about it on google. Could my fuel pump pressure be to high?
The float presntly sits at a 20-degree angle to the carb body, I'm planning on grinding down the grommet so it sits level & rotating the float so it actuates front to rear, not left or right.
Related question - when the manual says to oil something, what am I suppsed to use as oil? motor oil? I'm planning on putting a little wheelbearing grease on the throttle shaft and exterior of the jet (where it slides inside the housing). On the piston/dome, I'm planning on using a little motor oil on the housing, just to provide light lubrication.
This one has me stumped. How/why is this thing leaking? could I just have the jet adjusted too low so it doesn't close against the piston?
Thanks!
Rob