Starts great with Choke out. But then dies. (1 Viewer)

[fj40cm1980]

Hi all -- new this forum with a 1980 survivor that I recently purchased. Engine was running good when I purchased it and I've barely put any miles on it...just around town here and there.

Recently it just won't stay running unless I have the choke at least have way pulled (or foot on the gas a little). Even after I warm it up plenty, it just dies immediately upon pushing the choke all the way in. Eventually I need to push in the choke so its not idling so high but as soon as I do that...it dies.

I thought it was a fuse issue (when I discovered a blown one in my fuse box) -- it seemed to fix it for a bit and would stay running but then the fuse blew again. Now the fuse is not blown but I'm back to the same issue. I recently picked up a Haines manual and the wiring diagram and "I think" the fuse that was blown was ENG.

Any ideas?? ALL ideas are welcome...I'm drawing blanks.

Thank you in advance,
CM

 

[bhsdriller]

ENG fuse will kill power to the idle solenoid so makes sense.

Usually running with choke only is a vacuum leak. I'd start there

 

[sggoat]

Rebuild the carb--

 

[mattressking]

Quick steps to Learn how to diagnose a carbureted F/2F.

1. Check to make sure idle solenoid has power and clicks reliably.
2. Measure vacuum and slowly close choke until before it dies. See what it’s measuring.
3. Compression test (need a baseline)
4. What was done before this happened.
5. Download the FSM from cruiser cults website, trace the Engine fuse circuit and see what runs off it. Then you can diagnose your popping fuse.

Answer those questions then we will move on.

 

[mattressking]

Rebuild the carb--

Carbs are actually not usually the fault, just a good scapegoat.

 

[Michael Hanson]

Check for bad ground and chaffed wires.

 

[Engineer8000]

The 79/80 emissions computer controls the fuel cut solenoid, there can be bad solder joints on the emission computer connector, or the transistor that controls that in the computer could be bad.

 

[fj40cm1980]

Wow, thanks so much everyone! I'll spend some time looking into all this and will give an update asap.

 

[fj40cm1980]

The 79/80 emissions computer controls the fuel cut solenoid, there can be bad solder joints on the emission computer connector, or the transistor that controls that in the computer could be bad.

View attachment 3231898

This seems like it could be a likely culprit (since I've fiddled so much with carb, checked for vacuum links, etc). Do you know how I'd go about testing this?Ω

 

[OPMACHINE]

I had this issue on my 79, just reflow the solder on the plug.

 

[mattressking]

This seems like it could be a likely culprit (since I've fiddled so much with carb, checked for vacuum links, etc). Do you know how I'd go about testing this?Ω

View attachment 3234284

View attachment 3234285

Ignition on, not running, disconnect and reconnect solenoid plug, repeat to make sure it’s a strong click.

 

[fj40cm1980]

I had this issue on my 79, just reflow the solder on the plug.

Thank you. Any hot tips (no pun intended) on reflow soldering? I have a soldering gun...will try anything once haha

 

[fj40cm1980]

Ignition on, not running, disconnect and reconnect solenoid plug, repeat to make sure it’s a strong click.

I'm on it!

 

[fj40cm1980]

Ignition on, not running, disconnect and reconnect solenoid plug, repeat to make sure it’s a strong click.

I did jus that....and I get a consistent strong click every time I disconnect and connect the solenoid plug (located next to the carb). Assume this means both my ECM and my solenoid are good? Or maybe the solenoid still might be faulty (even thought its getting power and clicking)?

 

[mattressking]

I did jus that....and I get a consistent strong click every time I disconnect and connect the solenoid plug (located next to the carb). Assume this means both my ECM and my solenoid are good? Or maybe the solenoid still might be faulty (even thought its getting power and clicking)?

View attachment 3234320

Computer and solenoid are good then, computer could have an intermittent connection sometimes but for now that rules it out. Keep going through list now. If choking helps, look/listen for big vacuum leaks including a sticking egr.

 

[peesalot]

Idle circuit of carb got something in it, check filter first, then have a look in the bowl, IMO.

 

[fj40cm1980]

Computer and solenoid are good then, computer could have an intermittent connection sometimes but for now that rules it out. Keep going through list now. If choking helps, look/listen for big vacuum leaks including a sticking egr.

Computer and solenoid are good then, computer could have an intermittent connection sometimes but for now that rules it out. Keep going through list now. If choking helps, look/listen for big vacuum leaks including a sticking egr.

put it all back together…went for a drive and is idling (choke in after warming up). I can hear that slight kick down when it begins idling (perhaps when the solenoid engages). So, I presume it is intermittent after cleaning up ECM and reassembling OR it could have been the fuse terminal ground wires (?) that I secured on the back of this bolt with a nut. It was mounted in front between plastic fuse box and bracket. Maybe that was causing a poor ground? I don’t but thank you guys for the help.