F134 - Engine Dies After Several Minutes

Hi, I have been restoring a 1968 CJ5 with F134. The jeep belonged to my parents-in-law and was standing in a barn since 1999…. I thought a new carb and new fuel pump would get me started, but once I realized everything was either seized, dried up, broken or worn out I decided to make this a full restore. I have been working on this most weekends over the past 3.5 years. Everything has been either taken apart and cleaned/restored or replaced with new parts. This includes gearbox, transfer case and engine.

I am now at the point where I have been trying to get the engine to run after it reaches operating temperature and I am just having no luck. What is basically happening is when the engine gets ‘hot’ it dies on me. Sometimes I am able to restart it immediately but cannot give any gas/load - letting it idle will keep it alive. The longer I wait before a restart the better it runs until it gets to that point again (temperature related / too hot ?)

I am also able to replicate the issue where I give 70% throttle for maybe 20 seconds and then it dies as well. Carb bowl is full and spark is showing on spark tester. I only have done this when engine is warm and it has already died on me before.


Below are some items that might help with the diagnosis;

• Fuel is getting to carb (clear fuel filter installed near carb)
• Engine is getting spark (have spark tester in cyc 1)
• New ignition coil (does get hot) (has been replaced twice already)
• New distributor parts (have also tried complete new distributor)
• New Voltage regulator
• Ground is ok, have zero resistance and on block, plugs, generator, voltage regulator
• Solex carb (3 years old with first attempt to get it running) - has since been taken apart and cleaned thoroughly
• Original Generator (brought to shop to test, was making 16.5 volts) - When on Jeep I do not get past 13.3 on the battery though.
• New wiring loom from Walcks
• Thermostat is working and opens at right temperature.

I really focused on electronics the last 2 months but everything has been changed and double checked since. I find it hard to believe it is mechanical as I would hear something. I thought maybe engine overheating but coolant is at 190 and I can restart it rather quickly.. You would think you need to let it rest a while before you can restart.

I am at a loss and any direction/help would be appreciated.

As we all like pictures I add some for good fun.

 

Condensors have been giving people nightmares lately. I'd start there.

Then maybe a regulator on the fuel pressure. Solexes are picky and want very little fuel pressure. Maybe too much fuel is ok until it gets up to temp, then it floods out?

 

I have had the same issue with ballast resistors. Once hot they provide too much resistance. It is easy to check with a volt meter checking the voltage going to the coil.

 

Yeah I was thinking ballast resistor as well. Is your coil the type that needs one or not?

Lookin' good btw!

 

Welcome. Beautiful motor!

Never owned one, but I've seen discussions here in the past about Solexes icing up in the throat.

Also "fuel getting to the carb" isn't enough. Check both static pressure AND volume (output).

Your symptoms mimic a blocked line or filter - Have you tried back-blowing the fuel line? Gas cap venting okay?

 

Try a different coil. That sounds like a coil overheating to me.

 

I doubt it would vapor lock on the 'pressure' side of the pump.

But I'd move that line anyway.

 

Thanks everyone for your replies, very much appreciated !

I do not believe it is electrical as I have pretty much changed out those parts twice or three times by now.

I am not happy with the Solex indeed, so I will review the complete fuel process. The fuel line is pretty much where it was before, which does not say anything but thought it would be fine. I will place it somewhere else at least for testing purposes. I still have the carb that was on there when I got to it but it needs to be cleaned/rebuilt (could try to use that again for testing). It is not original as it does not have the right air inlet on top. I would ideally like an original one ! Can someone tell me to what this should belong to ?

thanks again

 

The OEM carb you should have is the Carter YF. It is not either of those pictured.

 

I'd trade you the original Carter YF off my 65 f-head for that Solex on the right in a hot *&^% minute.

 

YF in good tune works fine, as it has shown for 70 years.

But the thottle shaft can get loose with wear and may need to be bushed to restore original performance

 

Been running a solex on my F-head for 20 years. No complaints here. I'm running an electric chatterbox pump that only puts out a few psi, so no regulator needed.

 

I have zero complaints about my Solex. I've run it in place of two different YFs now, and used the stock mechical pump on both (an epump like ITLKSEZ would be a nice setup too). Both ran well after the swap. IMO the Solex is a nice cheap replacement and an improvement.

The YF served it's duty for 60+ years, and 'won the war' and all that lol . But, in neither of my cases was my effort a full restore to orig, so I wasnt married to it. I find the Solex much better to work on and get running WELL. To each their own though. Like I said, I'd certainly trade. Someone into more of a true restore could put my extra YF to better use than me.

 

I do want to try and keep most things original so my comment about original carb was 1) meant to keep vehicle original 2) not always impressed with modern replacement stuff.

It sounds like most of you speak highly of the solex so I'll keep it and maybe tear it down and see if something is wrong. There must be guys out there that run the carter with the solex and do not run into my issue ? Maybe a solex rebuild is in place here. It's been off the jeep for 3.5 years while I was restoring. Maybe it needs some TLC.

Yes, The fuel enrichment is all the way forward. I do need it to start and keep it open for quiet a while. Once everything is warmed up I put it all the way back. Throttle is responsive, but like I said it will just cut-off when properly warmed up. If I catch it on time the engine will stay on. But I can't put any load (read: give gas) or it will die. It will idle though.

After letting it rest for 10 minutes everything works until I hit that point again .. then I'm back to square one. I've been able to repeat this for the last 2 months now and I've literally changed out everything electrical except fuel pump and carb.

What fuel pump (No vacuum) would you recommend then in place of the carter ?

 

No, you just happened to find the only two on this site!