2f start but backfires and doesn't run with out keeping revs up (1 Viewer)

[Mkent305]

Hey guys so I finally got started on my old boys fj45 it's been sat in the shed for about 5 years now with out it moving. Iv pull off the electric flue pump and replace it with a new mechanical pump then replace the old factory carb with a holley 330 from my old 2f
But can't seem to get it running right it will start fine as I timed the ignition in with the new carbie. but now it won't run with out me keeping the revs up and it also backfires when I take my foot off then dies can someone help me

P.s I'm not much of a machine just a young fella trying to get the old girl back on the road cheers

 

[Grayscale]

Pull the spark plugs, clean them. It is a good treatment regardless of why it is running bad.

 

[charliemeyer007]

You most likely have a vacuum leak. Take a can of WD-40 with a pee tube. Lightly and quickly spray all the intake gasket surfaces while its running - when the rpm's kick up there is your leak. Put a hemostat on the brake booster hose.

 

[Mkent305]

Sorry for the last reply I finally had some free time to work on the rig I put new spark plugs and a brand new battery. it ran and idle but a little ruff still but alot better then the other day I also got some brake cleaner and sprayed around the intake I found a leak the rpm never picked up but just bubbles where the leaks was also did all the vacuum line they seem to be fine too so need to replace the intake gasket and see how it go's after that

 

[DesertFJ40]

Edit: just read you found the possible cause being an intake leak.

It sounds like it could be your idle solenoid. I had that issue while driving at speed. As long as I had my foot on the pedal, it would run. as soon as I let off, it would sputter and die.

For me, the fix was soldering a busted wire that went from my ignition coil to the idle solenoid on the back part on the carb. I wrapped it up with electrical tape afterward and it's been good for the past 5 years. never experienced the problem again. This was for a 1971 with original carb and engine. Hopefully its an easy fix and you don't need to replace the idle solenoid completely.

Or, maybe the timing is too retarded? Or maybe the idle speed on the carb is set too low? It should be 500rpm from what I recall. those are my other guesses.