67 k10 with a 2SE carb need help!

[67mater]

I am ready to give up on this integrated head 250 and the varajet 2se carb in particular. It starts up fine, but will only idle on almost full choke. I have been inside it 3 times now cleaning, etc. float has been adjusted (raised) per spec. Fuel filter(s) are clean. I have good fuel pressure and volume.

Someone had already cut open the idle mixture screw. It was out 6 turns, I have it out 4 now. Before I changed the idle mixture screw it would run on almost half choke, now at 4 turns it only runs on 3/4 choke. Any less and it stalls. clearly that was out to compensate for what seems to be a large vacuum leak. I can back it out a few more turns but feel like a bandiad.

I have adjusted timing and searched all over for vacuum leaks. I have every vacuum port capped except the vacuum advance (20" of vacuum on that line) and the fuel bowl vent line. Could the EGR be stuck open or something? I have not pulled the valve cover to look for cracks.

It has 8 gallons of fresh gas on top of maybe 4 of questionable gas. It starts right and revs up fine on 3/4 choke, which makes me think fuel isn't the primary issue. It has had the electric choke removed and the manual cable rigged up, but don't see how that's an issue. Anybody with experience on these can help me!!!

[Warrens69GMC]

Have you checked the diaphragm on the egr?

[weim55]

This probably isn’t what you want to hear but this is exactly what I would do: Unbolt the cylinder head from the engine and take every single piece from the cylinder head, intake manifold, exhaust, and carburetor, toss it all in the nearest dumpster. I worked on those late 80s varijet 250s when they were new and they were positively hideous. If your short block is in solid condition I would just get a complete topend with all the correct Accessories and carburetor for your year truck and put it back to its original configuration. Very reliable and simple set up. Or: Just purchased a 100% complete good running 250 take out motor from one of our trucks and just be done with it.

Steve weim55 Colorado

[67mater]

How can I check the egr diaphragm? Currently its unhooked and capped. There is also a sort of heat riser that is vacuum actuated but opens directly into the intake. That's hooked up to manifold vacuum, but I've run it unhooked and in the no vacuum.position without much difference.

I have found a 63 250 complete fir $250 that ill probably go get.

[67mater]

so I found a few things. first, what I believe is the EFE TVS which actuates the heat riser valve was bypassed so I have hooked back. I assume it wont see vacuum until the thermal vacuum switch warms up? yeah?

that also lead to seeing the hard vacuum line wrapping entirely around the back of the engine and under another, larger vacuum line right off the back of the manifold, which had a cracked fitting in the top of the valve cover (the red 90 degree fitting by the firewall). I have capped the line just to see if that was my vacuum leak. I'll also check that fitting at the manifold for leaks because I didn't know it was there!

the exhaust manifold is spidered with cracks anyways, I am just trying to see how good the bottom end of this motor is so I can decide if I am just doing a head swap or if I need to do a full engine swap. I'll fire it up at lunch and see if anything has improved.

[70STOVEBOLT]

With 20" of vacuum it should be a decent bottom end, but a compression/leakdown test would be a better indicator of that. I have basically a long block 250 out of my '70 I would sell but it's missing the carburetor and exhaust manifold and lower t-stat housing.

[67mater]

I played with it more last night but no change. Also lost the accelerator seal, so I have it torn apart again at the moment. Time for a rebuild or another plan.