Ignition diagnostic help?

[Neubie]

Hello all,

Seems every step forward I try and take gets me further behind....
After head gasket replacement, My 69 230 was running ok but for a lack of power. Went to set timing which was only done by ear initially. Set it to spec and the car would stall once in gear. I knew the points were shot so I got around to replacing them, and the sparks (Nkg) for good measure, cause it was running rich (if leaned out idle adjust, it wouldnt hold an idle.) Sure enough, sparks were black as can be. Now that all that was done, i cant get it to even idle in Park for more than 30 seconds. Yesterday it would turn over, but not fire, today after cleaning distributor cap (less than 500 miles old) contacts a bit and some fiddling it at least starts and runs long enough for me to run to the front of the car, but after initial start or unless ive got the throttle open it sputters and dies. when running it alternates (fairly quickly) between running rough (shuddering, bogging down) and sounding ok. If im lucky i get about 30 seconds of listening to it to try and figure out whats going on. I got a look at the dwell which is smack on 40 degrees (chiltons recommends 39-41) I got the timing light on it once and it was good at 1500 and 4000 but the mark was kind of jumping around, not steady.

Ive tried tweaking the distributor while running, but no position seems to be any better, some are worse.

Condensor was swapped out with distrib cap like I said, less than 500 miles ago. Coil hasnt been changed since I've owned the car.

Strange, cause like I said it wasnt running great, but it was running around town at least.

Any ideas or recommendations where I should start?

Thanks as always,

Marc

[lawson]

I have been there. It usually helps me to set my carbs back to bench settings and adjust from there. Also, clean the idle jets.

[Neubie]

So far, everybody has pretty unanimously agreed not to touch the carbs till ignition is dialed in. regardless, I can't get it running long enough to mess with the carbs even if I wanted to........

Front carb doesnt atomize spray very well, ie it sprays, but some comes out as droplets. Was planning on adressing this as a separate issue, but could you give a quick rundown on how to clean the idle jets for me?

thanks

Marc

[wbain5280]

Zenith info:

Interesting Zenith discovery

and...

http://jaimekop.com/CarbManual/index.html

[MunichTaxi]

Front carb doesnt atomize spray very well, ie it sprays, but some comes out as droplets.

You'll see a deterioated O ring that causes this problem, when you rebuild the carbs.

[t walgamuth]

i had a 280e that had a rotor in it that was a little too short.

it would start up and run reasonably well til it warmed up then just wouldnt run at all.

tom w

[230/8]

After reading your post it certainly sounds like you have sorted out your ignition issues. I suspect you really have a serious problem with your carburetors and what you need is to focus on that side of the engine. Zeniths can be intimidating at first glance and do not respond well to un-informed tinkering. But, once properly adjusted they will operate with little attention.

If you search the forum for "zenith adjustment" you will find a boat load of data on these old, much maligned, but basically sound carburetors and how to rebuild and properly adjust them. I am not a clever follow, so am unable to figure out how to link those old threads to this post. There must be a dozen good threads on this subject, most containing very good data.

You will be wise to get a few of the proper tools...a bonnet for the carb top so you can balance them, and a unisyn tool to measure the air flow through each carb. With these and a bit of patience you can have the Zentihs running just fine. Repair kits are available from Phil (this site) and others on the net. The carbs are fairly easy to rebuild if you take your time.

Tools can be found here:

http://www.baumtools.com/

Click on products and then keyword search "zenith."

Warren's link to the Jaime Kopp site manual is good. This is the factory manual.

Have patience, do some research, use a gentle hand to make small changes, and your 69 230 will give you many years of reliable transportation. Mine has served me well for 35 years.

230/8

[Blue 72 250]

I would back up and focus on the ignition again. Quote: "got the timing light on it once and it was good at 1500 and 4000 but the mark was kind of jumping around, not steady."

I had the same problem with my car- for $100 you can put in a crane unit and get the timing 100% dead on. This will make all of the difference in the world when it comes to adjustment on the zeniths.

The leanest mix will still cause dark plugs if the spark is late or intermitant.

[Neubie]

I may yet go that way with the ignition, but I figured Id try the $5 option first Will wrench again this weekend and see what I can do. Not ruling out faulty condensor, cap or rotor, but it was running well enough with those before changing points. At the moment she wont run steady enough to even take a stab at adjusting carbs.

Thanks for hanging in there with me, will report back....

Marc

[t walgamuth]

dont forget about the rotor length.

it is an odd ball thing but simple and very hard to detect.

of courese the crane conversion will eliminate this and a host of other potential problems.

tom w

[Blue 72 250]

Also should check the conectivity of the rotor. I bought a crappy one at a parts store and it was an "open" circuit from the center to the tip. I took it back and they said "no return on electric parts".... I don't buy from them anymore.

Another possibility is that the float on the carb is sticking and the bowl is running over. Do you see any fuel coming into the carb while it is idleing? Have you checked the inline screens that are a part of the carb? sometimes prior owners will pull the screens when they become clogged an not return them.

[Neubie]

Hey all,

Well, looked a bit further into my issues this weekend. Everything on the timing side seems ok or at least workable, so I switched over to the carb to take a look. Pulled the top plate and jet block on the front carb, disassembled and inspected and everything looked clean and free. Float measured out right and didnt seem to be leaking. Float valve free. Cleaned everything for good measure and put it back together. In looking further, I looked at the secondary diaphragm, and lo and behold, it was shot. Just a sliver still holding on. Pulled the aft one to check it and it was gone as well.

So, it may not be all the problem but it is a problem that can be fixed. Ordered up rebuild kit, pulled the jet block off the aft carb and will clean it up as well. Probably look into pulling carbs off and grinding down mating surface, I understand this is a common place for vacuum leaks....will also look into trying to free and close heat riser butterflies.

Anything else I should look for while Im in there? Any words of caution?

Were my symptoms (rough running,shuddering, and stalling unless throttle was wide open) indicitave of problems in the secondaries?

Thanks so much for the help and advice!

Marc