GSW38 Posted July 25, 2005 Share Posted July 25, 2005 My 1938 Buick 40 Fouls plugs.The fuel mixture is too rich. Is there a way to adjust the carb to fix this problem? Thanks George Link to comment Share on other sites More sharing options...
Guest ZondaC12 Posted July 26, 2005 Share Posted July 26, 2005 its funny i oughta know this although i havent touched the carb on mine yet. maybe thats why it blows some smoke, maybe i got the same problem! if no one beats me to it, ill scan in pictures of my shop manual section on the carburetor, im sure there must be some info there on mixture adjustments. theres too much stuff, i cant figure out whats what, it talks about "metering" and stuff like that and im clueless, i dont know what id do if i had to do major work on the carburetor right now. its probably simpler than i think but at first glance it looks confusing Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2005 Share Posted July 26, 2005 don't be a hero,just take the carb off and senfd it out to get rebuild and calibrated. Meaning, boiled out, gaskets, new acc pump, and floats measured. It will be the best $150 bucks you've every spent.It took me eight years to learn that. Look in Hemmings for a good guy. Larry Igross in Long Island is who I used. He Advertises in the AACA magizine. Link to comment Share on other sites More sharing options...
carbking Posted July 26, 2005 Share Posted July 26, 2005 Buick used both Marvel and Stromberg carbs are original equipment in 1938. If you have the Marvel, just replace it. If you have the Stromberg, it can be adjusted.Before throwing rocks at the carburetor, remember that 93 percent of the problems diagnosed as carburetor related are actually ignition. In order, I would suggest (A) compression test; ( hook up ignition to a diagnostic oscilloscope; and then © look at the carburetor.Jon. Link to comment Share on other sites More sharing options...
GSW38 Posted July 29, 2005 Author Share Posted July 29, 2005 Thanks for the info.In your message you said Larry Ingoss rebuilt your carburetor did you mean Larry Isgro from NY? Thanks George Link to comment Share on other sites More sharing options...
imported_paldo38 Posted August 28, 2005 Share Posted August 28, 2005 Buick also used Carter carbs in 1938 and later. In any case, John Hardgrove is a reputable carb rebuilder; email techpwb@thecarburetorshop.com with your carb details, and see what he advises. Link to comment Share on other sites More sharing options...
NTX5467 Posted August 29, 2005 Share Posted August 29, 2005 In any carb, there will be some calibration bleeds in the venturi/throttle body area. These will be in the upper area (typically) areas of the venturi area AND should be reasonably visible upon inspection with the air cleaner removed. If the earlier Carter is architectured as more modern ones are, there will be a hole for the idle circuit and one for the main circuit of each throttle bore/venturi in the venturi cluster. When that part of the calibration circuit "closes", it makes that particular circuit go "full rich" or being restricted can cause "too rich". Usually, these deposits are more fuel residue-related and can be removed with some good carb cleaner spray. In the bottom of the venturi cluster (again, if that earlier carb is like the later Carter carbs), the tubes that go down into the fuel will also have some caliabrated holes in them, but they are "supply" side rather than "additional calibration" side. When clogged or plugged, it causes "lean" issues rather than "rich" issues.As mentioned, ignition issues can cause some of the same things as fuel issues. A check of ignition point dwell and coil output might be appropriate, as well as spark plug gap. A too weak spark will not fully ignite even a correct fuel/air mixture, which might end up with what appears to be a "too rich" mixture (and point to a carb issue in the process).If the air bleed holes are clear and fully open, any richness should be able to adjusted "out" by the idle speed mixture screws. In the older carbs, there was enough latitude in the typical mixture adjustment range to cause a "rich" idle condition. Maybe the carb just needs a good carb cleaner "spray and soak" of the venturi area, some fresh spark plugs, and a good idle mixture/speed adjustment?Maybe it's a "sunk float" issue, possibly?Just some thoughts . . .NTX5467 Link to comment Share on other sites More sharing options...
Patrick W. Brooks Posted August 29, 2005 Share Posted August 29, 2005 Hello George: Could not add much to the many suggestions about the carb and related matters. However, several years ago I bought a 1940 Buick which was being sold by a very dissatisfied man who had only bought it two months before. He had many problems keeping it running and it would not even start when I got it. It was setting in my shop and would not even fire. I was struggling with the problem of why the car was acting this way when a retired mechanic friend who is in his 70's stopped in. We discussed the problem with the car and I decided to pull a plug and while examining it he pointed out it was a 12 volt plug. I immediately pulled a used set of 6 volt plugs off the shelf and installed them. The car started the first time over and ran fine with no fouling thereafter. The message is, be sure you have the right plugs or you can rebuild everything and still have the same problem. Patrick W. Brooks Link to comment Share on other sites More sharing options...
GSW38 Posted August 31, 2005 Author Share Posted August 31, 2005 Thanks Patrick for your information. My 38-Special calls for AC46 plugs.I have installed these they were fouled after about 100 miles. All eight(8) plugs were equally bad.After the plugs foul out I get a back fire through the carb.The carburetor on my buick is a stromberg AVV-1. What plug would be hotter than the AC46? Thanks George Link to comment Share on other sites More sharing options...
carbking Posted September 1, 2005 Share Posted September 1, 2005 George - the backfire through the carb, along with the fouling plugs indicate ignition problems (or valves).If possible, attach a diagnostic oscilloscope to the engine, and read the firing voltages. My guess is that your voltage is too low, but there may be other ignition related problems. The oscilloscope will tell you the condition of the ignition system.Jon. Link to comment Share on other sites More sharing options...
buford 8 Posted September 23, 2005 Share Posted September 23, 2005 Ha Ha Ha.... 12 volt and 6 volt plugs.... maybe if the battery is hooked up backwards the horn will suck instead of blow? Link to comment Share on other sites More sharing options...
GSW38 Posted October 21, 2005 Author Share Posted October 21, 2005 Found the problem. I was using an air filter not made for my 1938 buick it was starving the engine for air thus the rich air to fuel mixture.I would like to thank everone for their ideas on why my car was running so rich. Thanks again George Link to comment Share on other sites More sharing options...
Guest ZondaC12 Posted October 21, 2005 Share Posted October 21, 2005 that'll do it...congrats on finding out the problem! now rev it up and burn that sh- uh stuff outta there!!! Link to comment Share on other sites More sharing options...
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