Quick diagnoses on my 200

So I have the 200 in my 70 and its always ran decent. I thi k I k ow the problem and possible fixes but its been 20 plus years sonce diagnosing these things beyond a simple tune up.

Carb was rebuilt 3 months ago. I tuned it using a vacuum gauge and ran fine until today. Started idleing this morning in a sluggish fashion for just a few short moments. Then ran perfect going to work and coming back.

Started it up to pull I to garage a few hours later. Idled like complete crap and blue smoke started coming from tailpipe. Pulled into garage under its weak idle. Any pedal gave to it made it die.

Crank up again and more blue smoke and horrible idle. Took first 2 plugs out and they were covered in oil. The valve cover breather is stopped up when I try to suck air through it. Pcv valve seems good though.

In the process of doing compression test...changing plugs and changing valve cover filter. Going to clean carb too just for the sake of it.

If this doesnt fix things....and the compression test is good....what's the next step?

 

Might be as simple as valve stem seals. Search for a thread I made about the subject.

 

That's k9nda my next guess.

 

Plugged up crankcase ventilation system can give same indications as bad valve stem seals(which in reality aren't seals at all)... In these old engines are best described as umbrellas that deflect oil from the valve stem...

 

so i put in new pcv valve, new valve cover filter and cleaned the carb as much as possible without a rebuild. i cleaned the plugs that were in it with gas and put them back in...ran the engine around 2000rpms and mist sprayed about a quart of water down the carb for 10-15 mins. let it heat soak and resprayed. took plugs out and cleaned....then ran about 5 minutes to hopefully dry the cylinders out. the car smoked blue haze the entire time. i also ran a compression test. cyl 1,2 and 3 held at 130-140lbs. cyl 4, 5 and 6 held between 150-162lbs. i let all sit for 2 minutes before letting the pressure off. only one cyl dropped and that was only 2lbs.

going to try the new plugs just for a few minutes. if that doesnt fix it, then ill pull the valve cover and see if i can see if the valve seals are busted. i suspect thats the issue because last year when i was learning to read different vacuum gauge symptoms, it seemed to point to a sticking valve or valve issue of some sort. needle was slightly jumping around but not too much. the thing i cant understand is why EVERY plug has black soot on it after i clean them unless all of the seals are gone at the same time. the carb was set right and has ran fine for the last 2years minus a slight miss.

this all started yesterday morning. during warm up, idle went from 600rpm to 3oo for about 5 seconds then returned to normal. i drove to work and back just fine. then when cutting engine off, then back on to pull into garage, it went from 600rpms to 300 or less and surged from almost dead to 300 and started smoking. this is what it continues to do.

i will say that the pcv and filter on the valve cover were bad after checking them, but as stated ive changed those and problem still remains.

water level is normal and also changed oil and it had zero water in it.

am i over looking anything before i go any farther??

 

Update...I pulled the valve cover off and I see zero broken pieces of anything. I tried the new plugs and it ran fine for about 5 seconds then started sputtering again and smoking like before. I ran the engine for about 1 minute. Pulled the plugs and all of them are black and wet. Inside the cylinders still look wet. I also noticed that under my new grabber hood there is a fine mist of oil lining up perfectly with the valve cover filter on the front side. I have some oil mist also going back and hitting the fire wall on that side.

Should I try to run it and see if the smoking stops?? Or just go ahead and assume I need new valve seals?

 

Probably a carb problem, likely the power valve has ruptured...

Bad valve seals won't cause one to run bad, at least not for 400-500 milers... They run OK for that far without seals...

 

I'm running the stock carter 1 barrel carb. Theres not much too it....but I can completely tear it down I suppose.

 

Well you were somewhat correct. The spray pump diaphragm was tore....of course. This makes 3 times that's happened to me but its never spit out smoke. Going to rebuild it again and see what happens. At least this makes more sense as to why ALL plugs turn black.

Also what company makes a lot with quality parts? The spray pump diaphram shouldnt bust so easy.

 

well i dont know whats wrong with it at this point. i rebuilt the carb..replaced pcv valve and new breather on valve cover. new plugs...did compression test. took valve cover off. everything looks good. everything checks out good. ran perfect for about 10 seconds on new start up....then started stumbling again. started smoking blue haze. smelled more like hot exhaust rather than oil.all plugs look completly black after a 1 minute idle. wet with either oil or gas or both. not sure. and nw pcv valve is working as i can feel it vibrating on my finger when it idles.

when i unhook pcv valve it of course runs fast but the smoke goes away and engine seems smooth. any ideas or thoughts before i give up? i have $21k in stocks and cant cash them in for a few years so im hoping its something simple im overlooking.

 

Problem solved.....almost. I tried the carb off my sons car (72) and it runs fine now.

So I rebuilt my carb and it still floods rhe engine. I adjusted the float lower by 1/8" and it wont even idle without smoking. Time for a new carb?

 

If the needle and seat won't seal it will flood the engine no mater where you set the float level.

 

It seems to seat it when I manualy move it when its apart. What do I do to make it seat? New needle and seat from the new kit is being used.

 

It isn't likely the float, needle valve or seat, if so it's a 99.9% it'd be overflowing with gas...

 

At this point im stumped. Pulling the carb apart one last time before I just get another one. At least I now know it is the carb and not anything else.