IowaTom Posted March 16, 2022 Share Posted March 16, 2022 Guys - After blowing compressed air thru the gas line and installing a new tank & sender, she fired right up! Thank you all for the suggestions! Now I've got a question about the carb that came with my truck. The neighbor who sold her to me said he replaced the old one with this and I'd like to make an attempt at finding a good mix. Years ago I remember using a vacuum gauge to adjust the air-fuel screw for about 20". Would that still be applicable with this carb? Link to comment Share on other sites More sharing options...
Gary Lewis Posted March 16, 2022 Share Posted March 16, 2022 Glad you got it going! And yes, you should be able to get 20" of vacuum at idle. But in reality you just go for max vacuum, dropping the idle speed back to where you want it as it increases with the increased vacuum. And then give it 1/8 to 1/4 turn more open on the screw to make it slightly richer. Link to comment Share on other sites More sharing options...
IowaTom Posted March 17, 2022 Author Share Posted March 17, 2022 Glad you got it going! And yes, you should be able to get 20" of vacuum at idle. But in reality you just go for max vacuum, dropping the idle speed back to where you want it as it increases with the increased vacuum. And then give it 1/8 to 1/4 turn more open on the screw to make it slightly richer. Thanks, my friend! Link to comment Share on other sites More sharing options...
1986F150Six Posted March 17, 2022 Share Posted March 17, 2022 Thanks, my friend! On my 1986 with 4.9L [computer control removed], I found that with 20" vacuum at idle, pinging would occur when under a load. At ~18.5", all was good. Link to comment Share on other sites More sharing options...
IowaTom Posted March 18, 2022 Author Share Posted March 18, 2022 On my 1986 with 4.9L [computer control removed], I found that with 20" vacuum at idle, pinging would occur when under a load. At ~18.5", all was good. That appears to be the sweet spot for my engine, too. As for the old tank, cleaning it myself made no difference in the amount of crud. SO glad I bought a new one! If you're considering trying to DIY, fahgetaboutit! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 18, 2022 Share Posted March 18, 2022 That appears to be the sweet spot for my engine, too. As for the old tank, cleaning it myself made no difference in the amount of crud. SO glad I bought a new one! If you're considering trying to DIY, fahgetaboutit! I replaced my mid-ship tank recently because the straps or frame had fretted a pinhole leak that would make it wet if I filled up. I could smell gas but never found any drips. For $150 delivered with new straps it wasn't worth my time to even think about it. I'm glad too. 🙂 The new one appears powder coated or something. Much better than the last one I installed in the rear. Link to comment Share on other sites More sharing options...
1986F150Six Posted March 19, 2022 Share Posted March 19, 2022 I replaced my mid-ship tank recently because the straps or frame had fretted a pinhole leak that would make it wet if I filled up. I could smell gas but never found any drips. For $150 delivered with new straps it wasn't worth my time to even think about it. I'm glad too. 🙂 The new one appears powder coated or something. Much better than the last one I installed in the rear. Pardon the highjack, but this thread reminded me of something: For whatever it is worth, and the truck show is still far away, I have an original 16 gallon side tank and sending unit from a 1985 F150 truck which had 61K miles. If anyone is interested in originality, I could deliver to Skiatook. The engine was a 4.9L, so the sending unit does not have a fuel pump. Link to comment Share on other sites More sharing options...
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