What am d doing wrong

C

CPB

Junior Member
Hi All,
I have been trying to get my 48 running but I'm having issues with it barley idling and missing on acceleration. Dist was checked on a machine and checks out ok. I have new plugs with the correct gap, points, wires, rebuilt carb by kt and a new electric fuel pump. The gas is fresh and new fuel lines. At idle vacuum jumps radically 13" to 15" and at a high rpm vacuum gauge reads a very steady 18" I have been lurking in the background for years and really appreciate the wealth of information all of have to offer. Thank you for all your help

cpb
 
THe first thing to do is take a compression test. Remove all the plugs and lock the throttle wide open. Write down how much comp each cyl. has. You may have some bad valves. Let us know. Walt
 
I agree start with a compression test; but it does act like a vacuum leak. the easiest way to check for a vacuum leak is take an unlit torch, propane or acetylene (small tip) with the engine running wave the torch over the intake manifold gaskets to heads, and carburetor to intake manifold gasket if the RPM's increase and the engine smoothes out you have pin pointed your vacuum leak. Please use caution as a backfiring engine or extremely hot manifold could ignite the torch. I will assume no liability for fires of any kind. With that said I have never encountered a problem pin pointing vacuum leaks using this method.

Regards,

Brian
 
I don't think raw fuel is a good idea.Better to use carb cleaner or like product to spray around the carb & intake area.
 
I had same problems with my '47 mercury, running rough,tried different carbs. new plugs,wires, points,checked compression good(so I thought) come to fine out I had a valve stuck open. after fixing that it ran great. good luck.Rod
 
Put a new old stock condenser on it, not one from the parts store. Also if you used parts store points, change em with old stock ones
 
ck all your manifold to block bolts..torque them to specs,after you ck the gasket with propane test..(dont light the propane) sorry guys,i had to say that) wd 40 with squirt nozzle works pretty good also! make sure you plug off the wiper hose fitting or at least hook up the wiper hose!

carb gasket!!! accelerator pump for stumble!!

flatties are known to carbon up under the valves,result is poor compression,,poor idle,,old school is set throttle at about 1000 rpm..drizzle 50/50 mix of kero/oil down throat of carb.usually clears out the carbon and runs off the misquitoes..
 
flatties are known to carbon up under the valves,result is poor compression,,poor idle,,old school is set throttle at about 1000 rpm..drizzle 50/50 mix of kero/oil down throat of carb.usually clears out the carbon and runs off the misquitoes..

I've always used MMO for this application and it works well.:D
 
CPB,
Will the motor run with the idle mixture screws turned in all the way or
nearly all the way in ?
How much slop is there in the throttle shaft of the carb...when you attempt to wiggle it ?
If you wish get back to me at cas5845@yahoo.com
Charlie ny
 
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