I've tried to read as many of the "only running when choke pulled" threads as I could find but I'm still trying to figure this one out. The engine will run ok when choke is pulled and runs at around 1200 rpm with a low, steady vacuum reading around 12 (at sea level). At lower rpm it will die and pop back through the carb. I don't know of a way to get timing set correctly without being able to run at lower rpm. I'm trying to decide whether or not I should send my carb off for a pro rebuild, go with Sniper or if there is some other problem on the bottom end. If i have a manifold related leak or bottom end problem then I'm thinking going with Sniper won't help anything. Here's what I know and have done over the last several weeks:
Based on all of that is this still most likely a vacuum leak?
Could it be a camshaft problem?
If compression is good does that mean valves are at least close enough until I can adjust with a hot engine? Cylinder 3 is a bit low compared to the rest so that one might be off.
What should my vacuum reading be at 1200 rpm?
- 72 FJ40 F engine with unknown history
- Replaced head gasket and valve seals, cleaned carbon buildup off of valves, cylinders looked good
- Cold valve adjustment when putting back together and will be checking valves again today (cold check again since I have manifold removed)
- Vacuum reading from fitting on the manifold in front of carb, brake booster vacuum line plugged
- Manifolds machined for flat surface, gasket from an engine gasket set bought through good vendor, will likely try remflex gasket next
- Large cap FJ60 distributor, I added a vacuum port to the carb and it has been capped during this process
- Dry compression test 1-6: 150, 158, 140, 160, 160, 160
- Idle solenoid confirmed working and clicks, since my vacuum reading at 1200 rpm is low I'm assuming that means the idle circuit is not the problem
- Rotor is pointing at number 1 plug connection when timing mark is lined up with the line on the flywheel
- PCV is connected to the insulator below the carb to the PCV valve and I did not plug this during testing
- New exhaust system
- I rebuilt the carb and certainly could have messed something up during that process
Based on all of that is this still most likely a vacuum leak?
Could it be a camshaft problem?
If compression is good does that mean valves are at least close enough until I can adjust with a hot engine? Cylinder 3 is a bit low compared to the rest so that one might be off.
What should my vacuum reading be at 1200 rpm?