It seems the bowl on the carb is drawing after it sits for a day or so. It takes about 10 seconds of cranking then a few pumps to get it to fire. It could be a number of things from what I read but I'm not sure which one.

1.) I could have this not tuned right and have vacuum on the port when the manual says it needs to be zero?

2.) a bad o ring?

3.) a re-build is in order?

4.) ethanol mix gasoline evaporates much quicker than normal straight gas?

I have been thinking about pulling the carb and filling the bowl up and watching and seeing if it leaks by slowly somehow.

Anyone have any ideas or good direction? I know an electric fuel pump would help fill it up much quicker without all the cranking but that just masks the problem.

 

Oh also after driving it, it's really hard to start it after it's been off for like 15 mins if I run into a store or something.

 

If its been on the truck for sometime and ran fine its not #1 (I'm assuming it is/was a new carb) Likely not #4, we've had crapanol in Canada for years and never heard of it evaporating out of the bowl. (My 83 sits in the shed from December to April and takes 2 or 3 10-15 second cranks tops and away she goes) If you have the EVAP system still, could be some weird vacuum issue with the gas tank. Likely its 2 and/or 3, so I'd rebuild the carb. Pay attention to the accelerator pump diaphragms. I had the same hot start issue with the factory carb you're having and found a tear in this. I had Weber 40DCOE's on a 80 Celica but cant recall if they had hot idle but that could be the problem in your case too.

 

I have come to learn that every carbureted vehicle has a "code" to get it started. The start "code" for one vehicle may not work for another.

For my Pop's '55 Chevy pickup (454 big block) the code for a cold start is two full pumps of the gas and about a 2 second turn on the ignition. For a warm start, it is a quick half pump of the gas and a quick bump on the ignition.

For my '83 Pickup the code for a cold start is holding the gas down at about 1/4 throttle while giving it a quick bump start. If it doesn't start on the first attempt (which it usually does), then I have to give it a couple full pumps of gas, let off the gas completely and crank for about 3-5 seconds until it fires. For a warm start on my truck, I just bump the ignition - no gas at all. I have yet to have to choke it since I finished up the restoration.

For your truck, cold starts are going to be dodgy - you are essentially relying on the fuel left in the bowl to start the truck long enough for the mechanical fuel pump to catch up. If you go to cold crank it and it almost starts up on the first try (but doesn't) then the following attempts are going to take a little longer because you have essentially blown your chance of firing it with the fuel in the bowl. That's why you likely have to feather the throttle a little bit to get it to stay running until the fuel pump catches up again (and also to keep it running until the engine gets warm on colder days). If you don't get it to fire on the first attempt like I described above, then give it a couple pumps of gas and leave the throttle alone (you don't want to flood the engine) while you crank. Just crank until you start to get some fire then you can try feathering the throttle a bit. As long as you have good oil pressure, there is nothing wrong with extended cranking. This is also what I USE ONLY PUROLATOR OIL FILTERS - there are other filters out there that have them, but I know for a FACT that Purolator filters have an anti flow back valve in them to keep the oil from draining out of the engine when it is off. Fram filters do not have this feature and are terrible oil filters for any vehicle that sits for extended periods of time. Without an anti flow back valve you are essentially cranking the engine dry until the oil pump pushes oil through the engine.

For your warm starts. Just stay off the gas. It should just be a bump and go. Even on my engine, it won't start up properly if I give it gas before warm starting it. If you are still having troubles warm starting then you may need to lean out the mixture a bit - an engine will run seemingly well with a slightly rich mixture but will not start well. Also check your timing. If your timing is set too far advance at idle then you could have hard starting issues. To that same effect, bad spark from your spark source power could be causing a hard start issue. This could be caused by a bad ground, bad coil wire, bad battery or anything that is isolated to the spark initiated when the engine is NOT running off of the alternator. So you could have a bad ground at the coil, bad ground on the engine, bad ground on the battery to the chassis/block/body/head or simply a weak battery. Once your engine fires, the alternator takes over powering the engine thus the majority of the grounds/power needed to spark air/fuel during start-up are no longer needed.

Hope this helps. Send me a message if you need any more.

 

I'm gonna double check my float levels just be safe. Saw this video:

[YOUTUBE] [/YOUTUBE]

I guess I'm not very good at leaning it out/setting the mixture. Warm starts are just as difficult as cold starts. The timing is 8 degrees, had a light to set it with.

 

Ok float settings were way off. I bought a small caliper and used to it set the heights of 51/35mm. Here is bowl after top was removed.



Some gas in there, but what I noticed was when I removed the fuel line nothing drained out of the hose. So maybe the fuel drains back or something when the truck is off?

Mixture screw is at 1 and 1/4 right now. Sounds pretty good but take that for what it's worth lol.

 

Was this before or after adjusting? Anyone else know if this looks right? I'm readjusting now for the same problem.

 

ONCE I had to address this problem on someone else's truck. We installed a check valve in the fuel line between the tank & pump and it worked. Seems the tank had some mild vacuum to it, which was drawing the fuel from the line back to the tank, leaving the line between tank & pump empty. Still not sure why it was doing this. Toyota never installed a fuel line check valve stock.

 

Thanks, turns out my float level was too low, and that seems to have fixed it for now. I guess it drifted lower than it was. I removed my holley pressure regulator, onto which I had just installed a gauge. I thought maybe I got a fragment of teflon tape in it when I was doing that. Removing it seemed to help for one day and it was back to really long cranks first thing. I found out my float was adjusted to 51mm instead of 35, which was book level, but there's a vid of a guy who seems to have been in the business of Webers for a long time citing this book value and showing you not only to adjust to 35, but to limit the travel of the float to 2mm. Never explains why. I did that and I was back in business. Smelled a little richer at idle, but it's always smelled too rich at idle as a Weber. Anyway I put the regulator back on after that trying to remedy that richness but it's not excessive, it didn't change it but I tested it with ther long, hard accell uphill on a highway and it never starves for gas like before, so I know the float is good. I could retune for the idle jet again and see if it's different. During this time I also upjetted at frist the secondary idle and then the secondary main 9putting the secondary idle back as it was) and each of those jets in their separate tests have eliminated the mid to upper acelleration flat spot.

Now that's all done, I am back to like it was beforee on the cold starts, 2-3 quick consecutive attempts to easily start from dead cold in the morning. Once it achieves idle, it starts first crank until it sits for 10-12 hours or more. I might be able to get it to go in 2 attempts if I loosen the choke flaps back up a little. Maybe check valves would help it start quicker, I've been eyeing some $1.50 ones on ebay. There's got to be something to the amount of time it was taking just to get the float level high enough to start that was taking so long. So much cranking, so little fuel, my lines must be empty. I changed the fuel pump recently enough and even that filled the line without missing a beat in that moment with the engine having been run the same day. Theres got to be a thermal cycle with the whole truck temperature causing a vacuum like you described.