I am having a terrible hesitation issue with a carb I bought and come to find out it was for a F5A instead of a F6A, so I contacted the person that sold it and he says they use the same carb, I have literarily exhausted everything and can't get rid of this hesitation,, where can I buy a F6A card with a manual choke?
I have read through almost all of the posts and about 8 pages in they are still having problems with their ideas, like starting with ether, vacuum leaks from the mounting flanges, still having a boog or hesitation off of an idle, etc.
Have you set the best lean idle? And, the high idle when the choke is engaged? You get stumble when the AF ratio is out of whack. Setting the best lean idle with the truck warmed up, will help get it into the correct range across the board. To set the best lean idle, you set the idle speed down to at least a couple of hundred rpm below the normal idle. This is to make sure the carburetor is not so far open it is already into the transfer to the main running phase. You then start turning in the idle mixture screw a bit at a time. If when you turn it in, the rpm goes up, your mixture is too rich. Turn the idle back down, and turn it in a bit more, and see if the rpm rises. Keep turning it in and adjusting the idle speed until the idle drops. Then turn it back to where it last was, and then reset the idle upto share it should be. If when you turn the idle screw in, the rpm drops, then you were lean, and you need to start getting richer. You need to progressively turn the idle screw out, and keep resetting the idle speed until it drops and go until it drops off, and then go back bit, and rest teh idle to the normal level. After you set the best lean idle, you need to adjust the high idle speed with the choke fully closed and the engine cold. Most of our trucks don’t have a high idle speed in the manuals. I set the one on my Hijet to 350-rpm above the 950-rpm idle speed, or 1300-rpm. Mostly because the factory manual for my 77 Toyota Hilux, used 350-rpm above the idle speed of 750-rpm. The truck starts well at subzero temperatures, and has good drive ability. So, I think I guessed right.
thank you so very much for the detailed adjustment info, I am now looking for a carb jetted for a F6A instead of a F5A with a manual choke
Properly adjusted, the wet choke on these trucks works quite well. And, as these carbs are constant velocity type the jetting is pretty much going to be close unless you have done mods to the exhaust system.
this truck stays at a hunting lease and only gets used 4-5 times a year, I know setting and not using is not good but that's the case here, the plunger that closes the choke doesn't like the setting for several months, we keep the gas treated but the choking for cold starts is the issue