29 if it don't start

[RickBrinker]

I put a Zenith Carb on my 29 DeSoto last year i need to adjust the carb and can't find the book.(I put it where I wouldn't lose it)There are two adjustments one on the bowl and one at the top where it bolts to the Manifold which adjustment is which.Thanks

[carbking]

PROBABLY the one at the top would be idle, and the one on the bowl the high speed.

Jon.

[RickBrinker]

Thanks a BUNCH

[Paul Bohlig]

I have a Zenith 267 updraft after market carb and the initial get it to run specs are:

Throttle screw 1 and 1/2 turns open

Idle 1 turn open

Main 1 and 1/2 to 2 turns open

I remember I had trouble sensing when the main was set correctly. You probably need to play with or find a carb guy who has an 'ear' for doing the final setting

Paul

[RickBrinker]

Thanks

[Rusty_OToole]

Years ago when setting up a 1930s Harley flathead 74 an old time mechanic told me to adjust it so the engine "barked" when I opened the throttle.

[RickBrinker]

Just had the Engine rebuilt having trouble getting it started

I've had to use either to get it to start and then keep it at 1/4 throttle to keep it running I think I've got the plug wires in the right place,maybe the timing is still off.I pulled the plug out of number 6 cyl stuck the rod in and brought it up to top dead center on the comp stoke one number 1 cyl I must have some thing else wrong ?????

[JACK M]

If it wont start on gas something is wrong. Either will melt down your pistons.

[nearchoclatetown]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JACK M</div><div class="ubbcode-body">If it wont start on gas something is wrong. Either will melt down your pistons. </div></div>Rick, I agree. You should not need or want ether to get it started. Something else is haywire.

[RickBrinker]

Well if it don't start by the weekend,I'll get the enclosed trailer and take it to my building and the #$%^$%$#@ won't see the light of day until I'm dead and gone !!!!!

[RickBrinker]

Well its trying to stay running with the choke 3/4 of the way on ??????

[nearchoclatetown]

Rick, it's trying to tell you it too lean.

[carbking]

Rick - the use of a choke is necessary to start an engine with an updraft carburetor.

Once started, some choke will be necessary on a well-tuned carburetor (depending on ambient temperature) until the engine warms completely. Once the engine has reached normal operating temperature, no choke should be needed.

Also, the engine should not be expected to idle at normal idle speed until the engine is at normal operating temperature. Modern downdraft carburetors utilize a "fast idle cam" which is connected to the choke to run the engine at a fast idle until the engine has obtained normal operating temperature. Very few updraft carburetors have this feature, thus the operator is expected to control the engine speed until the engine is at normal temperature.

Freshly rebuilt engines require a richer carburetor adjustment until the engine is broken in. The new parts need to become acquainted with each other.☺ We normally increase the idle fuel by about 30~50 percent during breakin (first 1000 miles) and then readjust. Main metering circuit adjustment may also need some additional fuel, but a much less percentage than the idle circuit.

And if you live in an area where you must burn deathanol, both the idle and main metering circuits may need adjustment.

Don't throw in the towel; others have had these issues and solved them, you can as well.

If you wish, call during normal telephone hours, and I will try to explain further.

Jon.

[Paul Bohlig]

I agree with carbking and he knows a million times what I do since this is his business.

From my experience he is absolutely correct. These old 6 cylinder updraft engines are cold blooded if not cold hearted. On my '28 Dodge Standard 6 the choke is definitely needed until warm up. This may take 5 to 10 minutes or more even at the 60 degree daytime temp in Akron this time of year.

Agree 3/4 choke a bit much.

When I ran the Zenith I often did not turn off the gas at the vacuum tank wishfully thinking I would drive the car again soon. Several months later it would not start. There are more solids in gas than you would think which become varish when the VOC's evaporate.

So, from my experience:

1. Add an in line fuel filter either 1/4 or 5/16 from NAPA. As close to the carb as feasible.

2. If yours has a vacuum tank fuel pump tank off the top fittings but not the top to see if the filter screen is clogged. If mechanical fuel pump add a filter before the pump. Consider removing the gas tank and flushing. I think I got a 5 pound coffee worth of crud can out of mine 30 years ago !!!

3. Assume the engine rebuilder simply removed the intake and of course exhaust manifolds but did not rebuild your carb. So, take carb off and soak outside in new gas or carb cleaner covering the carb. Remove idle and main jet pins and blow carb cleaner through carb. Use air compressor to clean the carb. Maybe throw out the gas cleaner (kills weeds well) and repeat.

4. Once it runs well and it will add that shut off valve and with the engine at operating temperature and running turn off the shut off valve until the fuel in the carb is consumed. As the engine stalls goose it a couple of times with throttle to use up the gas.

5. Look for an after market airfilter. I use a NAPA motorcycle filter with adapotor in the summer. The old hot air pipe FORD used and others copied worked but so, so.

Do not give up

Paul

[Jan Arnett]

Paul:

I would not put the fuel filter next to the carb. I would put it on the inlet side of the vac tank which is the suction side going to the fuel tank.

Have a nice day

[RickBrinker]

Well I think the valve timing off I don't have any vacuum at the carb. so it can't suck fuel.

[Jim Anselmo]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RickBrinker</div><div class="ubbcode-body">Well I think the valve timing off I don't have any vacuum at the carb. so it can't suck fuel. </div></div>

Can you look at the valves with the covers off and see if they are moving like you would expect in relatioship to the piston? Just a thought...

[Paul Bohlig]

I stand corrected. Actually my fuel filter is between the fuel tank (inside the driver side frame rail) and the electric fuel pump and mechanical regulator which I use to bypass the vacuum tank. I know, I know the vac tanks worked for decades.

Thanks for catching my mistake. The plastic fuel filter near the exhaust could, would be a disaster.

Now about the no vac at the carb?

Bad leaky gaskets at carb, to intake to engine? Reused gaskets on these connections?

Beats me but the idea of taking off the valve covers off is good. Also, maybe remove spark plugs to ease load on battery while turning over?

How could it run at 3/4 open choke if no vac?

Paul

[RickBrinker]

I shot either into a spark plug hole to start it then kept it

at 1/4 throttle and it barely stayed running for 5 min

[RickBrinker]

The engine has about 45lbs compression but has no vacuum at the carb.Valve timing ?

[RickBrinker]

Still doesn't start