wont idle without choke

[NickDawson]

Nick, did you rebuild this carb?

No, the furthest I've ever gotten into it is removing the jets and blowing them out. Earlier in this thread you'll see my attempt to ream the main jet out, which may very well be the root cause of the current issues.

Its running more smoothly today, but still not well

I'm proud of how far I've gotten on my own, but think I'm going to take it in to a shop tomorrow.....and/or.... call these folks http://www.piercemanifolds.com

Of course I keep saying I'm going to do that and then I start tinkering again and get closer still. Im learning a lot sitting out there with books and manuals, seeing what does what...

[kevkon]

Good for you Nick, sometimes we all have to learn the hard way.
It may be that a fuel circuit in the carb is blocked, you might want to get another ( new 0r rebuilt ) carb. Not too many mechanics today are good with carbs and even if they are the labor bill will probably be more than a carb. You might also get a carb re-build kit in addition and learn the workings of the mysterios beast. Then you will have the knowledge and a spare on hand.

[NickDawson]

Seriously, thought this thread was behind me :/

Strange symptoms - the truck randomly began running fine. And then sometimes it wont. And then its fine again....

When it first starts, it bucks a fair amount, almost like fuel starvation...but pretty soon, sooner if I back off the throttle, it smooths out. The random part is that I can drive all over time and sometimes it is bucky and sometimes not...totally depends. I'll be in 4th doing 45 and it starts bucking, I back off the throttle a bit and it smooths out and boom, I can punch it and it runs fine for a while.

Hills, both declines and inclines have no bearing. Neither does engine temp.

When it bucks, it also backfires or gurgles a bit. The timing is good, according to the light, may benefit from a fine tune, but not too far out of whack. The points are in good shape and gaped well. I've sorted out my grounded positive lead to the carb's fuel shut off solenoid (fixed the dieseling at shutoff too).

So - I have positive fuel pressure at idle, but how would I know during running conditions? I think it is either the jets in the carb (which would be my doing when I was troubleshooting the early on in this thread)....or it is the ignition - seems unlikely since I have consistent spark, good points, good voltages, etc

I've learned more this go round than any other time (and you all know there have been many )- a lot of it due to the encouragement to really study the systems and read more - thanks gang!

I feel like I'm close to solving this one... and on the verge of buying a pentronix and some new jets and maybe an electric fuel pump...but given my druthers, I'd like to know what exactly is wrong and stage those purchases appropriately.

Any more trouble shooting tips?

[bkreutz]

If you've still got a conventional ignition in it, and an old condenser lying around, try throwing the condenser in and see what happens. The reason I mention this is that I've had failing condensers give me fits over the years, I had one with almost the exact symptoms you described, went through the carbs a couple of times, replaced the fuel pump, nothing changed. Then on a whim (or desperation) I changed the condenser and the problem went away. This happened a long time ago (1972) and I've run into this a few times since then, but I always remembered the first one so when I get a bunch of strange symptoms that don't make sense, I change the condenser. Might be worth a shot.

[bmohan55]

From what I've read here and other places and in talking with mechanics the quality of condensers now a days are "spotty" to day the least. I'm starting my engine rebuild this weekend (with help from a friend) and will be putting in a pertronix because of this fact.

Nick, I have an old condenser from a 25d (never gave me problems) and an unused back-up laying around if you want to try them...if they will work in a 45d?

[daveb]

is the fuel system clean and the filter clear? you could be getting blockages in the fuel pickup though in my experience those are not intermittent, once you are blocked you stay blocked.

could be a sticking float or float valve too. when you are on the gas pedal you are draining the float bowl more quickly, letting off would allow it to refill. lower float level means leaner running. have you checked the float setting? If you do that it would not hurt to change the needle in the float bowl valve while you are at it.

[NickDawson]

Great news! I swapped out the condenser for one I had wiht an older (but good) set of points - its running like a top!!!

Knock on wood that it keeps running for a while

This thread has been a real evolution for me in troubleshooting and fixing. Got the carb solenoid sorted out, detected and replaced a bad coil and tracked down the bucking to the condenser.

Thanks everyone!

[bkreutz]

Good to hear. My Rover is the only "old" vehicle I have that still has points. I'm still debating this in my mind. Everything else I have has been switched to Pertronix because of the unavailability of OE quality condensers. There still seems to be a supply of NOS ignition parts for these so I'll probably leave the points in until the spares start coming in a box marked "Made in (fill in the Asian country of choice)" When I started as a mechanic, there was no electronic ignition and a condenser failure was almost unheard of, of course normal tuneup schedule was every year or 12000 miles, so I guess they didn't stay in there very long.