52 hornet twin h popping back through carbs

karl

My 52 hornet will not start after setting all winter. Always ran fine and started easy. Ran good when parked in dry garage. Anyhow, upon trying to start car turned over and started to backfire or pop through both carbs. Engine is stock with exception of Petronics ignition. still 6 volts. I  changed out  from known running engine; dist and cap with wires, coil . I checked compression and found 90 to 60 psi . Plugs are dry  Tried priming carbs and even starting fluid. No change. Could the valves be stuck? Engine always ran smooth with no smoke. I used 91 octaine non ethanol fuel which you can by at the pump in upstate NY. I used a couple of gallons from same supply in my lawn mower and it ran fine. Need help. Couldn't go to Doc's meet in Va. I have owned car for 20 years and did a valve job about 15 years ago.Time flys when you are having fun. The way it ran I just can't believe it jumped time at chain end. Thanks,Karl

Uncle Josh

One or more of the intake valves are stuck open, and it's firing through the open valve..  You should get a low reading on the cylinder affected. 

Try squirting solvent through plug holes.  Put a 12V starter battery on it with some gas squirted down the open plug hole 

Have some Mystery oil, Sea Foam etc ready to dribble down the carbs if it starts.

Ol racer

fyi

Compression is more than 10# uneven but still should start. They can be finicky sometimes after setting all winter up North especially with little lower compression, Perhape it jumped Time while trying to start. Suggest remove # 1 S/Plug then crank over with remote Button or Assistant to bring #1 to TDC.... ( Hold Thumb over hole until pops yourthumb off) then remove Distributor Cap to look if Rotor is pointing at #1 Plug Wire. If not, it Jumped Time and needs a Chain.....

karl

Thanks for tips. I put Marvel oil in top of carbs and in each cylinder. I let it set over night after I spun it over a few times. Now It doesn't pop through  carbs but still won't start with 12 volt help . I guess the Marvel oil helped. I turned engine over to what I think is the timing mark on the flywheel. When at this point the rotor is at no.1. It's very hard to see timing marks. So I hope I'm right. Does this prove the timing is correct. I am sure the dist. is in correctly as it will only go in on way into the oil pump. Does this prove the timing chain didn't jump?

Uncle Josh

Ah, pull the two 1/4-20 screws holding the pan under the flywheel, then rotate the flywheel so you can clean it with kero or something then chalk the grooves so you can see them.

With the flywheel at TDC, the timing can either be at #1 or #6, that's why you need to do the thumb thing like Ol Racer says. to make sure you're at #1

karl

I found timing marks and the rotor lines up with # 1 and # 6 just like old racer says. However. It seems like the thumb test blowing my my finger off, the rotor is at #6. How does it look like its out 180.  How could it jumped time exactly 180 degrees? I know the firing order is 1 5 3 6 2 4. The distributor can only go in one way, right? As I said before , the wires,cap and dist. came out of a running 308 As you can tell I don't want to tackle the timing chain. Am I doing something wrong or can't see the forest for the trees? 

Glowplug

The engine was running last time before Spring resurrection so the wiring on cap to plugs and the mechanical timing is a-ok.  You confirmed same with the thumb test and mark check.  Uncle josh has noted that this malady was also the product of sticking valves.  I add my support to his diagnosis....stuck valves. Spray them via the plug holes with a lubricant and try to free the sticky ones.  

Rocket88

Karl: 

I put Marvel oil in top of carbs and in each cylinder. I let it set over night after I spun it over a few times. Now It doesn't pop through  carbs but still won't start with 12 volt help.

Answer:
The plugs might be fouled with the oil used to free up the valves which is either causing no firing = no popping back, or no firing = no running.

Pull the plugs and clean them, then try starting it again. 

Ol racer

fyi

If the Rotor is pointing at #6 when #1 is at TDC,switch the wires to that Rotor position then try start. I wouldn't think it would Jump that far though, but think about it... if you did NOT have the Distributor out, or change the S/plug Wiring Order, it must have jumped....

karl

I just rotated the spark plug wires so that the old #1 position  was moved to # 6 and it started right up. Old farmer was right on with the thumb in #1 . I caused all the confusion  as I swapped out the dist , wires etc. from my other Hudson Hornet engine. I think the original problem was stuck intake valves which the Marvel mystery oil solved.     I just assumed that #1 WAS THE SAME FROM BOTH ENGINES!!!. THANK YOU SO MUCH FOR SOLVING  THE MESS I CREATED. KARL