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GB SISSON 07-15-2020 10:04 PM

Stumbling, hunting and missing
 

No, not another elk camp story.....My homebuilt woodie has a recently overhauled 221 replacement block set up as a 59ab. It developed a miss at #3 cyl and I finally traced it to a very black, corroded terminal in the crab distributor cap. New cap, now running on all eight! During the shotgun approach to tracing it down I swapped out both the distributor and carb. Now I'm finding new symptoms and poor running. The current distributor came off the 59 ab I pulled when I installed a diesel engine in the tonner. Fresh Bubba with the echlin condensor etc. Running a blue bosch coil 12v neg ground. Ran well on the otherwise worn engine. Carb is a 91-99 that I bought a few years back from an enthusiast here on another island. It was in the shipping box from Jere Jobe, well known carb guru and never installed. Here is my question of the evening. This carb was built for the owner's 255 cu in 59ab in 47 woodie. If I recall it also had a mild cam. Is this perhaps too much carb for my little, stock 221? On the flat at 30 it surges and hunts and lurches. On the long grades it stumbles and sputters some. Fuel tank is new poly and two filters. Also have an inline electric fuel pump that has been in the car since built with no problems. The pump has a switch and used for after sitting startups. Hitting the switch while climbing hills has no effect. On my last trip, yesterday, I drove it hard coming up my hill and killed the ignition and coasted to the shop. This morning I pulled the plugs and they were uniformly a sort of chocolate brown. Not white, not black, not the perfect tan, but clean looking and ok I think. Just not sure what to check tomorrow. The Jere Job carb is beautiful and totally rebuilt. Could it have jets too large? If so are they the jets reached horizontally through the bottom of the float bowl or the vertical ones by the acc pump nozzles, which btw, squirt with authority. To those of you guys that know this stuff and haven't fallen asleep reading this, thanks, and I will check back in the morning. ZZZZZZZZ

solidaxle 07-16-2020 12:25 PM

Re: Stumbling, hunting and missing
 

As you describe, it sounds to rich. Hook up a vacuum gauge, it should pull around a steady 20 at idle warmed up. You can preform many tests to show the condition and symptoms of a motor. Google a chart for a vacuum gauge.


Other things to check first.
Correct plugs
Old and worn out plugs
Gaped correctly
Timing


Good Luck

GB SISSON 07-16-2020 02:58 PM

Re: Stumbling, hunting and missing
 

Thanks! I'm in the midst of the trouble shooting now since it's lunchtime. My son is sanding a bunch of drawer fronts in the shop so I'm gonna sneak out and do the vacuum test. Maybe a compression test for yucks. I honed the cyls (no ridge) and put in a set of hastings rings, new valves, lifters and guides, ground and lapped seats and had crank turned /new bearings about 3000 miles ago. My wife was heading to town so I called napa and they had the FA54 condensor in stock, so she's picking one up just in case I start chasing ignition.

FlatheadTed 07-16-2020 03:47 PM

Re: Stumbling, hunting and missing
 

White plugs ?? ,carbs blocked or lean condition ,refit the other carb then road test ,

GB SISSON 07-16-2020 04:20 PM

Re: Stumbling, hunting and missing
 

Quote:

Originally Posted by FlatheadTed (Post 1909840)
White plugs ?? ,carbs blocked or lean condition ,refit the other carb then road test ,

Not white, I said brown. Kind of a dark brown....

FlatheadTed 07-16-2020 04:51 PM

Re: Stumbling, hunting and missing
 

Brown can be still lean try it with choke out ,should pick up on power ,rich will be black but still run ,at idle if the exhaust blows black smoke its Rich

Step-down 07-16-2020 05:07 PM

Re: Stumbling, hunting and missing
 

With adjustable timing light check advance at 2000 rpm
Build pointer and mark pulley

FlatheadTed 07-16-2020 05:46 PM

Re: Stumbling, hunting and missing
 

Sounds like you may have answered your own question ,try another carb ,

FlatheadTed 07-16-2020 10:05 PM

Re: Stumbling, hunting and missing
 

Sorry GB i misread ,

Mart 07-17-2020 03:03 AM

Re: Stumbling, hunting and missing
 

91-99 is a holley/ford "94" This has the jets inside horizontally at the front. Take big plugs out, undo with appropriately sized screwdriver (Might need grinding to go in). Jets should be 51s or 50s.

The jets that squirt from the top are accelerator pump jets and only work when opening the throttle. In steady state they are not squirting.

Having reread your original post I would swap back in the previous distributor and carb. They ran well before, they should do again. The fault was the cap.

That might be the simplest way of troubleshooting the new problem. The new problem was introduced when fixing the old problem, so undo what you did. Make the cap the only change.

Mart.

GB SISSON 07-17-2020 02:52 PM

Re: Stumbling, hunting and missing
 

Well, it's friday afternoon. Haven't had much time for a test ride, but the spark was intermittent so I swapped out the condensor and it was blue and regular. Vacuum gauge was dead steady and needle splitting the 20 mark now also. I think I found the culprit. And now Mart, I have a spare carb and distributor to take along in my kit. I have not driven it yet, but all signs are good. I will report back soon.

GB SISSON 07-23-2020 06:22 PM

Re: Stumbling, hunting and missing
 

A week ago I thought I had it all figured out. But when I finally got a chance to test drive it, all was still the same. I put the old ugly carb back on it. Still the same. Today with the help of my son we swapped the other distributor back in like Mart (smart) said. Voila! Steady acceleration, pulls really well, runs smooth on the flat and the idle is smooth as silk. So the big problem was the cap. When I pulled old woodie into the garage I heard a loud hissing sound and I remembered why I swapped out that distributor a year ago. The gasket was perfect and so was the little donut. I also greased the gasket this morning on installation. I pulled the vacuum tube from the intake and now of course I had a vacuum leak, but it still ran ok sort of. Then I capped off the tube at the intake and ran (idled) really smooth with no sucking sound up front. I remember running that dis that way for quite a few months with no issues. So now I'm heading out for a test drive with no vacuum to the distributor. I'm thinking it will still perform well. Question of the night.... What harm would/could be done running with the vac plugged off? Thanks. GB

FlatheadTed 07-23-2020 06:59 PM

Re: Stumbling, hunting and missing
 

GB ,Its good you got the original problem solved ,I don't think it will bother you that much (youv run it like that ) you have the centrifugal advance (weights ) that will not be working with no vacuum It will be retarded slightly some cars run hot sutch as a model A .but just watch the temp /heat ,others may have input ,

GB SISSON 07-23-2020 07:34 PM

Re: Stumbling, hunting and missing
 

Ran great. Pulled really well and ran steady. After removing it I studied the distributor that wasn't performing right had some bad pits on the points. It had an old style condensor with the steel strap instead of a wire. I may have put that on there last year. Perhaps this condensor was bad causing the pits. I know Bubba is a fan of the modern napa condensor, and I may have swapped it out during troubleshooting. My island has a population of about 4000 people and I'm the only flathead guy I know of. You guys are my source of knowledge and I do a lot of backyard testing to get my stuff figured out, but electricity, like mathematics has always been mysterious to me. I'm the guy that tested offshore lifters with a device I built with a 12" piece of rod welded to a socket and hung a 5 lb sack of flour to test the tension of adjusters. I can see that stuff..... But microfarads? Ain't gonna happen. Anyhow, running retarded is what's probably what's gonna happen for the rest of the summer.

Tinker 07-24-2020 12:27 AM

Re: Stumbling, hunting and missing
 

Electronics can be a bit of wizard stuff. But it's really not that hard. 90% of the time it's fuel related. As a solid electric system works... most of the time, if fuel cooperates.

GB SISSON 08-21-2020 01:21 PM

Re: Stumbling, hunting and missing
 

While the performance is vastly improved, I sill get some missing or cutting out at WOT on the long grades. I did look at the main jets and they are 50s. Might it help to try a set of 51s that I have? I am at sea level to about 1000' on a daily basis. There's a possibility I may do the East/West flathead run next month. That's around 4000', and talk about a long uphill grade......


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