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Nervous at 60
icebergstu - November 26th, 2015 at 08:48 PM

Poor old girl has forgotten her incontinance pads and is all nervous 3 days before Volksfest.

56 Stockie

Massive bog off idle. Huge Flat Spot.

Quick History: Ran fine, perfect. Then started being funny and seemed to starve if full throttle or High RPM for a long time. Completely conk out 3/4 of the way up a long hill. Would have to wait a minute and wind it over until it started again. Did this for 2 months and I got used to it.
Started it one morning a few days ago and it is doing this extremely annoying flat spot thing.

What I have done so far:

Pulled carb off, completely dismantled it down to the butterflys.
Used liberal amounts of carb cleaner on all parts and blown out with compressed air.
Re-Assembled
Same issue...
Saw what might be an air leak in the manifold - caked it up so it wouldnt lead.

What next?

I was thinking an air leak in the intake manifold somewhere else...?

One bonus....she runs great up hills now with no starve issue so I fixed something??? Poor old girl, imagine how many times that crank has gone around in 60 years...

http://i425.photobucket.com/albums/pp337/icebergstu/20130216_143222_HDR_zps3bfac8a1.jpg

Stu

icebergstu - November 27th, 2015 at 01:55 PM

Bump...Anyone got any ideas???

Stu

icebergstu - November 27th, 2015 at 07:38 PM

Quote:
Originally posted by ragged
I think you have more than one problem. Firstly, is it squirting fuel out of the accelerator pump jet when you open the throttle? If not, that will produce a flat spot when ever you put your foot down on the accelerator. Is there a delay before it begins to work?
Secondly, if you are losing power under load, it may be a fuel delivery problem. There may be a restriction in the fuel line, a bend in the tube, or a valve in the fuel pump not sealing properly, just to name a few.
Thirdly, there may be an ignition problem. Points may need replacing or gap adjusted. Timing may be retarded due to the points closing up. Timing may need adjusting, or the advance mechanism in the distributor may not be doing it's thing.
Important thing is, firstly adjust tappets (every 3000 miles) and give the motor a compression test to check the condition of the mechanicals.
Secondly, Replace or re gap your spark plugs, Check the resistance of you H/T leads and connectors, adjust the points and timing, check that the timing is advancing as the engine speed increases.
Now if you still have a problem, go back to the carburettor.
Dave


Thanks Dave,

I will do all that after Sundays Volksfest.

Stu

psimitar - November 27th, 2015 at 07:41 PM

I once had the non return ball bearing in the accelerator pump gallery stick firmly in place even after much carb cleaner was used to try and free it. So just saying that unless you can see fuel coming out the nozzle then you could still have a problem. Even pin head holes in the accel pump diaphragm.

Best way to rule out carb base leaks is to check the manifold flange with a straight edge and the carb bottom. Over time the steel manifold flange pulls up on the stud ends giving a concave surface and hence constant leaks.

If the head ends of the manifold are still tight then unlikely that the copper gasket has stopped sealing but to chenge them is a bit of a bugger.

Then you should check the vac advance can is still working properly and the vac plate in the dizzy can move freely. If the vac advance doesn't work then a flat spot ye shall have.

icebergstu - November 28th, 2015 at 10:48 AM

To have a relatively sudden flat spot im my experience always points firstly to a blockage in the carb, hence the strip and clean.
The Acc Pump membane is definietely past its prime and a carby kit has been sorced from Ebay.
A fuel Pump kit has also been sorced.
Spark Plugs cause missing not flat spots 99.0% of the time.
Points, timing, dosnt just jump out and cause flat spots. You can feel the difference in a 36HP engine when playing with the dizzy and advancing or retarding it. Point gaps causes missing or hard starting.

When I pull the carb off again I will aslo take the inlet manifold off and inspect if for holes. It has corossion in the heat tubes but not in the manifold that I can see.

If I put my foot on the accellerator from low revs it, bogs (Engine Cuts out completely) then sometimes will backfire through the carb and get going again. To me it all points to fuel delivery.

Thanks for the imput guys. Its great to get others perspectives as someone always thinks of something you dont. I appreciate it!

Stu

turboboy - November 28th, 2015 at 02:04 PM

Maybe rust in the tank blocking supply line, try blowing back up line to see if there is anything restricting on outlet of the tank.

Rich

ancientbugger - November 30th, 2015 at 07:32 AM

Try a new condenser and start keeping a diary of what goes wrong and how you fixed them. I've just had troubles with a lot younger car and it turned out to be the condenser with symptoms not dissimilar to yours that I had not had before in over 40 years of VW ownership.See "incessant cutting out" thread , I assumed it was fuel as well.