What am I missing?! 78 with Trollhole Carb which has worked great until now.
All of a sudden, over the past couple of days, my rig won't idle once it has warmed up unless the choke is pulled out pretty much all the way. I can get it to lug along at 5-600rpm at 80%choke. It's clearly starving for fuel-if I give it a little shot of carb cleaner, it speeds right up.
I've checked the idle solenoid. I pulled it, cleaned it out (wasn't dirty), tested that I can blow through it when energized and can't when not. Fuse is good, but for good measure I hot-wired the solenoid to the battery and ran a separate ground from the carb to battery negative. While the solenoid was out, I sprayed carb cleaner in the opening and blew it out with compressed air.
Idle mixture screw. Pulled it, cleaned it (wasn't dirty), sprayed carb cleaner and compressed air and reinstalled it.
Vacuum. I only have 3 lines. PCV, Brake Booster, and vac advance. All of the lines and connectors are new. I sprayed them with carb cleaner and eventually disconnected and plugged everything. I sprayed all over the carb and manifold and vacuum lines and the only minor leak I have is at the throttle shaft, but that has always had a minor leak.
Fuel filter is new and fuel appears to be running freely. Air cleaner on or off doesn't matter. It does generate some vacuum in the fuel tank, so I tried it with NO gas cap. No difference.
Level of fuel in the carb window is not quite in the middle of the glass but at the top of the dog bone-maybe 1/8" low. It has always been there-even when it was running well. When I installed the carb I checked the intake manifold for the crack that you sometimes see in the bottom. It looked perfect. I have sprayed all over the intake manifold and see no sign of vacuum leakage.
I've got a newish ground cable from engine to frame and frame to battery. And I ran a separate one for testing from the carb mounting bolt to the battery.
Otherwise, it runs fine. I had it out for an hour today and except for having to pull the choke when I pulled up to a red light, I had no issues at all.
WHAT AM I MISSING?
All of a sudden, over the past couple of days, my rig won't idle once it has warmed up unless the choke is pulled out pretty much all the way. I can get it to lug along at 5-600rpm at 80%choke. It's clearly starving for fuel-if I give it a little shot of carb cleaner, it speeds right up.
I've checked the idle solenoid. I pulled it, cleaned it out (wasn't dirty), tested that I can blow through it when energized and can't when not. Fuse is good, but for good measure I hot-wired the solenoid to the battery and ran a separate ground from the carb to battery negative. While the solenoid was out, I sprayed carb cleaner in the opening and blew it out with compressed air.
Idle mixture screw. Pulled it, cleaned it (wasn't dirty), sprayed carb cleaner and compressed air and reinstalled it.
Vacuum. I only have 3 lines. PCV, Brake Booster, and vac advance. All of the lines and connectors are new. I sprayed them with carb cleaner and eventually disconnected and plugged everything. I sprayed all over the carb and manifold and vacuum lines and the only minor leak I have is at the throttle shaft, but that has always had a minor leak.
Fuel filter is new and fuel appears to be running freely. Air cleaner on or off doesn't matter. It does generate some vacuum in the fuel tank, so I tried it with NO gas cap. No difference.
Level of fuel in the carb window is not quite in the middle of the glass but at the top of the dog bone-maybe 1/8" low. It has always been there-even when it was running well. When I installed the carb I checked the intake manifold for the crack that you sometimes see in the bottom. It looked perfect. I have sprayed all over the intake manifold and see no sign of vacuum leakage.
I've got a newish ground cable from engine to frame and frame to battery. And I ran a separate one for testing from the carb mounting bolt to the battery.
Otherwise, it runs fine. I had it out for an hour today and except for having to pull the choke when I pulled up to a red light, I had no issues at all.
WHAT AM I MISSING?
