Hmm, mine looks similar to that... But also looks slightly different. I am curious if maybe they tried to modify it or something. This is what mine looks like underneath where that ball and cylinder is.
Hmm, mine looks similar to that... But also looks slightly different. I am curious if maybe they tried to modify it or something. This is what mine looks like underneath where that ball and cylinder is.
Yes. It's definitely been "modified." The small valve is missing and I bet the ball was jammed in the valve's guide to prevent a vacuum leak. This isn't good. If someone tried to disable the MCV, what other modifications might they have tried that could compromise the carb? If you can't get the Weber soon or you're intent on trying to get the Mikuni to work, plug the rectangular opening in cylindrical part of the MCV valve body with JB Weld (visible in your latest pic) and the other smaller holes with RTV, then reassemble. That should plug the passages from the air horn to below the secondary throttle and any vacuum leaks caused by disabling the MCV.Originally Posted by MidnightPass
The MCV has a very limited purpose; it only opens momentarily when the throttle closes quickly to prevent an overly rich mixture. If the rest of the carb is fine, it should start and be drivable despite an inoperable MCV.
I overlooked your post #6. Why was the truck sitting so long?
Last edited by FMS88; 04-29-2022 at 08:56 PM.
I am not sure exactly why it was sitting for so long, nor how long it was sitting for. I know it sat for at least six months, but other indicators say it was longer than that even. I was told the guy I bought it from was selling it because the carb needed work and he didn’t have time to work on it. It Did not run for at least those 6 months though. But from the smell of the fuel I drained from the tank, I would say it sat for even longer than that.
Hopefully the PO is right and it just needs a carb and fuel system cleaning. How did the rest of the engine appear and test? Okay I hope.
With the carb how it is, I was able to run the truck off of ether for basically however long I wanted, but the engine sounded beautiful ��
Also, I figure it should be a good thing to mention, the truck would crank up and run for about 2 seconds then die and not start back up for about 2 to 5 minutes… Then do the same thing again.
Good to see that it will fire up and run even briefly. Still, I'd test the compression just to be sure it doesn't suggest another reason it was parked. Not sure about the failure to restart. My first guess would be an ignition problem (coil, ballast resistor, distributor, timing). Check what you can before replacing parts and especially the coil/distributor wiring. The PO might have tried to get creative with the ignition system, too.
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