Engine Buttoned up - But Issues
07-15-2017, 01:25 AM
#1
Engine Buttoned up - But Issues
Hey guys,
Got my engine installed and all buttoned up. Trying to work out the kinks.
I had it running last weekend. Had a hell of a time getting it going, but finally managed to get it to idle. Got it dialed down to about 850 RPM, but I was having trouble getting a proper vacuum reading. I was getting about 5" at idle. Increases significantly with RPM. At around 1500 I had about 15". At any rate, after screwing around with the idle mixture I was about to get it to about 6". Timing set to 12 degrees BTDC. Got tired of screwing with it and decided to hang it up.
Fast forward to today. I turn the key, it starts, and immediately dies. Okay, pump the gas, turn the key, starts and revs up to about 1200RPM and then dies again. Long story short, it won't stay running unless I feather the crap out of it or hold the RPMs up around 2000. If I try to keep the RPMS up around 2000, it will stay running. Any lower than that and it'll peter out and die without feathering it. There's also a barely noticeable surge if I hold the pedal steady.
Things I've tried: Swapped Distributor, verified plug wires\firing order, checked for vacuum leaks via an unlit propane torch (found none), capped all vacuum\PCV ports, pulled the valve covers to make sure there were no broken springs\loose rockers, pulled the top of the carb off to verify floats weren't hung up or something dumb like that, checked plugs (look sooty\rich), tested fuel pressure (4.5 PSI). I'm sure I'm forgetting stuff.
I'm hoping a fresh pair of eyes might shine some light on things. At this point I'm about to pull the intake to make sure there's no leaks there. The super low vacuum is really bugging me, and instantly makes me think there's a vacuum leak but I'll be damned if I can find one.
Any advice on where to hunt next?
Thanks,
Mike
Got my engine installed and all buttoned up. Trying to work out the kinks.
I had it running last weekend. Had a hell of a time getting it going, but finally managed to get it to idle. Got it dialed down to about 850 RPM, but I was having trouble getting a proper vacuum reading. I was getting about 5" at idle. Increases significantly with RPM. At around 1500 I had about 15". At any rate, after screwing around with the idle mixture I was about to get it to about 6". Timing set to 12 degrees BTDC. Got tired of screwing with it and decided to hang it up.
Fast forward to today. I turn the key, it starts, and immediately dies. Okay, pump the gas, turn the key, starts and revs up to about 1200RPM and then dies again. Long story short, it won't stay running unless I feather the crap out of it or hold the RPMs up around 2000. If I try to keep the RPMS up around 2000, it will stay running. Any lower than that and it'll peter out and die without feathering it. There's also a barely noticeable surge if I hold the pedal steady.
Things I've tried: Swapped Distributor, verified plug wires\firing order, checked for vacuum leaks via an unlit propane torch (found none), capped all vacuum\PCV ports, pulled the valve covers to make sure there were no broken springs\loose rockers, pulled the top of the carb off to verify floats weren't hung up or something dumb like that, checked plugs (look sooty\rich), tested fuel pressure (4.5 PSI). I'm sure I'm forgetting stuff.
I'm hoping a fresh pair of eyes might shine some light on things. At this point I'm about to pull the intake to make sure there's no leaks there. The super low vacuum is really bugging me, and instantly makes me think there's a vacuum leak but I'll be damned if I can find one.
Any advice on where to hunt next?
Thanks,
Mike
Last edited by Jorlain; 07-15-2017 at 01:30 AM.
07-15-2017, 07:23 AM
#2
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,029
Received 1,663 Likes
on
1,261 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Engine Buttoned up - But Issues
Sounds like the idle system in the carb isn't working (i.e. not feeding fuel).
Borrow a carb that won't take too much effort to put on; or, tear that one down and look for obstructions in the passages.
Borrow a carb that won't take too much effort to put on; or, tear that one down and look for obstructions in the passages.
07-15-2017, 05:49 PM
#3
Re: Engine Buttoned up - But Issues
Idle circuit must've been the issue. I pulled the carb off, completely tore it down, and cleaned the crap out of it. Everything seems to be working fine now, although I still can only muster about 7" of vacuum at an idle of about 850 RPM.
Thanks again, Sofa!
Thanks again, Sofa!