2f Carb Tuning - Timing - and Vacuum Routing for Desmog (1 Viewer)

[Seth S]

Tonight I did the idle mixture screw adjustment. It was straight forward enough and helped but I think I’ll be doing a carb rebuild anyways and getting some propane to check for vacuum leaks. Also need to check my valves too. Depending on how they are I may do the lean drop again. Didn’t have a vac gage handy this time but next I’ll have one.

 

[dannyvp]

I’m working on the truck now. I have the carb adjusted some and the idle is around 700 ish on the dash. I have black smoke from my tail pipe though.

 

[dannyvp]

This was suppose to be a video, i'll try again.

 

[dannyvp]

<a data-flickr-embed="true" href="" title="Fj60 carb tuning"><img src="https://live.staticflickr.com/31337/48132996298_d3941d4912_z.jpg" width="360" height="640" alt="Fj60 carb tuning"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

 

[Seth S]

Black smoke is usually an indicator of being too rich.

 

[dannyvp]

Black smoke is usually an indicator of being too rich.

Yes I don't know how to fix that. Ideas?

 

[4Cruisers]

Yes I don't know how to fix that. Ideas?

Check your main and secondary jet sizes.

 

[dannyvp]

Check your main and secondary jet sizes.

That’s above my pay grade I think. This is a brand new carb. Maybe I’ll call cityracer.

 

[mattressking]

You need a timing light, tachometer, vacuum gauge if you want to set it correctly and accurately as possible without using a wideband.

1. Start truck up and drive it around to operating temp. Park and leave at idle.
2. Unplug Vacuum Advance vacuum lines from both vacuum advance ports and cap off.
3. Hook up Timing light and verify timing is set to the BB which is 7* BTDC.
4. Remove timing light, reconnect vacuum lines.
5. Check vacuum reading. You want at least 18inHg if at sea level.
6. Bring idle to 690rpms using only the idle SPEED screw.
7. Use Idle MIXTURE screw and rotate coutnerclockwise 1/4-1/2 turn at a time then race motor a few times to settle in the change. If idle raises, use idle SPEED screw to bring idle back to 690rpms.
8. Repeat step 6 and 7 until idle no longer raises.
9. Using idle MIXTURE screw, turn it in roughly 1/8th of a turn at a time, racing motor between changes to read idle. Bring idle down to 650rpms. Shouldn't take much adjustment to lower from 690 to 650. race motor a couple more times and watch idle.
10. Check vacuum again. Hopefully you are still at 18inHg or above. If not, there are vacuum leaksor other issues that need addressing.

 

[4Cruisers]

That’s above my pay grade I think. This is a brand new carb. Maybe I’ll call cityracer.

He can tell you the jet sizes installed in the carb. You're probably OK because I would imagine the default jet sizes would be appropriate for at or near sea level.

 

[Seth S]

FYI I picked up a vacuum gage at oreily auto parts tonight it was 25.99.

 

[Seth S]

Second try.

 

[NeverGiveUpYota]

View attachment 2013465

This was suppose to be a video, i'll try again.

When I hooked up my City Racer the first time the truck was idling so low I was barely able to distinguish it was running. It was around 300, I was blown away.

How much black smoke? And yeah you need a vacguage asap. That would really really help, simply to know if your holding well too.

 

[NeverGiveUpYota]

<a data-flickr-embed="true" href="" title="Fj60 carb tuning"><img src="https://live.staticflickr.com/31337/48132996298_d3941d4912_z.jpg" width="360" height="640" alt="Fj60 carb tuning"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Download to YouTube and add the link. That flicker thing doesn’t seem to be working, at least not for me.

 

[dannyvp]

Well yesterday i thought i had it tuned up well enough to travel a bit, RPM's were around 700-800 still burning rich. On the way to work after about 5 miles when i shifted and depressed the clutch the RPM's shot up to 3800. I put it back in 4th real quick and it went back to 2500. When i shifted in neutral same thing, if i pull the choke out though it will run at about 1200 rpm's.
You can feel the truck pulling me if that makes sense. Looks like i'll start over in a while and see what's up.

 

[Seth S]

With the clutch in try stabbing the throttle pedal quickly a time or two....it sounds like the linkage may be sticking. I was having the exact same problem this spring when I pulled the truck out of winter storage. I fixed it by greasing the two pivot balls on the throttle linkage arm...hasn't done that since.

these:

Carefully pull that little clip out and the ball end will pop right out. clean the ball and mating socket as best as possible...I used copper anti-sieze on mine because I figured grease would just run out...probably could use some graphite grease or some other high temp resistant lube. Then put them back into the socket and reinsert the pins.

 

[Seth S]

Have you done the "Lean Drop Method" adjustment yet?

 

[dannyvp]

With the clutch in try stabbing the throttle pedal quickly a time or two....it sounds like the linkage may be sticking. I was having the exact same problem this spring when I pulled the truck out of winter storage. I fixed it by greasing the two pivot balls on the throttle linkage arm...hasn't done that since.

these:

Carefully pull that little clip out and the ball end will pop right out. clean the ball and mating socket as best as possible...I used copper anti-sieze on mine because I figured grease would just run out...probably could use some graphite grease or some other high temp resistant lube. Then put them back into the socket and reinsert the pins.

I put grease on them and this seems to have fixed the problem. Thanks! They were greased when I put them in, but maybe not enough.

 

[dannyvp]

Have you done the "Lean Drop Method" adjustment yet?

I have not, my Fluke does not support RPM’s.
When I get back in town in a few weeks, I’m going to buy a vacuum tester and do it.

 

[Seth S]

If the city racer carb out of the box idled at 300rpm it’s very likely set to a basic default. Did the carb come with any docs on setup?

The lean drop tune works....I think....because as you turn the idle mixture screw CCW it leans out the carb and that causes the rpm to increase. I bet you could turn the idle speed screw back to get the idle down to 300ish....just enough to hold the idle. Then turn the mixture screw CCW 1/8th to 1/4 turn at a time and listen for increase in rpms. Reference the dash tach for now. Keep turning that screw out until the rpms stop rising. If the engine speed increases a lot in the process you can slow it back down to the 700 ballpark with the idle speed screw. This wont get you to the end setting but it may get you closer until you can get some proper gages.

Which fluke do you have?