Guest rwolf Posted May 17, 2006 Share Posted May 17, 2006 After checking and re-checking everything related to the ignition on my '24 4-cly I decided to put back the original carb. It solved the evasive back-firing problem but the car has much less power than with the replacement carb. Can somepone advise me how to adjust the Marvel carb? Link to comment Share on other sites More sharing options...
Guest Posted May 18, 2006 Share Posted May 18, 2006 join the free 1927 buick group linked below... we love marvels! Link to comment Share on other sites More sharing options...
old_truck_nut Posted May 22, 2006 Share Posted May 22, 2006 Have you tried putting a vacuum gauge on your engine?Few engine testers are more useful and versatile than a vacuum gauge, yet very few of us shade tree mechanics use them. A vacuum gauge can pin point valve and valve spring problems, carburetor and timing problems and more. Check out this site: http://www.secondchancegarage.com/public/186.cfm to learn all that this inexpensive tool can do for you.Let us know what the gauge tells you! Whitney Link to comment Share on other sites More sharing options...
Guest Posted May 23, 2006 Share Posted May 23, 2006 ok,if the engine has no power, it's not getting gas.the wheel at the bottom of the carb is for idle. open it up 1/2 rotation, and increase 1/4 turn until you get a smooth idle. under 25mph, the low port powers the car.Next, if you are getting a popping noise in the intake as you try to go fast, you are to lean.these car only have to carb ports. low and high speed.the high port only takes over after 25mph. there is no adjustment on this.so.... run it with a lot of choke and see if you get power.if you do, your air flap valve is to lose, or the spring is stuck. the air valve is suppost to be 1/16" off the valve body wall when the car is off. you have to pull the heat riser off to check. if you do pull your heat riser off, check for holes in the innner pipe. if you have hole, your exhaust is getting sucked into your intake, and that could be your problem.all else fails, take the bottom off the carb and blow thru your ports and see if they are clogged. you can make your own gaskets, any air leak will prevent the fuel from being sucked into the intake. Link to comment Share on other sites More sharing options...
Old26Buick Posted May 23, 2006 Share Posted May 23, 2006 If you find holes in inner pipe,I have found a method of elimating the pipe use.I blocked my off and still left all the pipes. Rund super now. Thats on a 26 Standard. Good Luck Link to comment Share on other sites More sharing options...
Guest rwolf Posted June 1, 2006 Share Posted June 1, 2006 I've adjusted the carb as suggested and idled it for close to an hour with Marvel Mystery Oil. The vacumn went from a fluctuating 14-16 " to a much more steady ( but still vibrating ) 15". I think I'm on the right track getting those valves free but now I have an overheating problem when driving. I havn't really had a chance to check it out. Link to comment Share on other sites More sharing options...
old_truck_nut Posted June 1, 2006 Share Posted June 1, 2006 Robert,Retarded spark will cause over heating. Advance the spark and you should see the vacuum increase. Try to get 17"Hg.I'm getting my Marvel back from the rebuild shop soon and will be hoping to get my ol' gal ('23-4 cyl) fired up after a 40 some year nap. Link to comment Share on other sites More sharing options...
Ivan Saxton Posted June 27, 2006 Share Posted June 27, 2006 I have a Radco tune-up manual from which I can scan the relevant pages for you if you are still in need. The late Duesenberg expert Jerry Gebby told me the story from the time he was involved with Buick why they changed from the fixed head engine with valve cages, to a detacheable head in the early 20's, if anyone is interested.Ivan Saxton Link to comment Share on other sites More sharing options...
Guest rwolf Posted June 28, 2006 Share Posted June 28, 2006 Hey Ivan, I'm interested, also,you never know what data could be useful. I have a 32 chevy that is timed differently than the manual(thanks to some advice) and it runs like a dream. So ,if you have the time please provide what you can. <img src="http://forums.aaca.org/images/graemlins/smirk.gif" alt="" /> Link to comment Share on other sites More sharing options...
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