Manx Club

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PostPosted: Tue Oct 03, 2017 5:19 am 
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Joined: Wed Apr 07, 2010 5:00 am
Posts: 399
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14 degrees before top dead center is little more than most set timing at idle. I use between 8 to 10 degrees at idle with total advance approx. 30-32 degrees total with a 009 or the early 010 distributors at 3,000RPMs.
Having a distributor where you can set the advance curve sound neat. Did it come with a basic advance program with it?

Good to hear you could get it to idle with larger jets.
The 110 cam is a good cam for all around performance.
Usually has good power from idle to around 5,000RPMs. Will run smoother with dual single throat carbs and even better with dual dual throat carbs like Weber 40mm IDF or the Empi HPMX.

Your compression numbers are not really that high. A guess would be somewhere around 8 to 1 compression ratio.

It sounds like the off idle stumble you are having is the accelerator pump circuit is not giving enough fuel when you open the throttle plate. On the Weber progressives I worked on (has been a few years) had different holes to locate the pivot pin for the accelerator pump to get more or less fuel out of the nozzle located inside the primary throat. Or it could be the nozzle has a blockage or needs to be enlarge to allow more fuel to flow.

Does John have any information at Aircooled.net about adjusting the accelerator pump or adjusting or opening up the nozzle?
Yes adjusting the air/fuel mixture idle screw is difficult. I have use the small pocket screwdrivers sideways and even bent them to get the angle I needed to move the screw. It takes time to adjust because of it being so close to fan housing.

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Joseph
Manx Club #1095
Having fun with Buggies since 1970
Worked in VWs in shops since 1970


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PostPosted: Sun Feb 25, 2018 4:19 am 
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Joined: Tue Mar 10, 2015 5:13 pm
Posts: 27
Location: Hemet/San Diego
I did take most of November and December off of buggy work.After much hair-pulling and all that comes with diagnosing problems that seem to not have a source I have determined that the main culprit in all of my motor troubles were caused by a faulty distributor. It was brand new, as was most everything on the engine including the carburetor, and it did not work properly. It was replaced with a well used 009 and starts and runs great. The electronic unit would check out on every test but still ran poorly. I could check timing and it would appear to be correct, but I could not check it all the time. The electronic unit had a persistent hard start and a constant hesitation off idle, more like a misfire that would act as if two cylinders did not work, it would idle but not accelerate without being very slow on the accelerator to just waiting for it to pick up. This was more than frustrating when driving around town and getting honked at. And I would not dare to do anything to have it stall, because starting was very hard even warm. All of these symptoms to me and others pointed to carb jetting issues so that is what I attempted to solve. I even received help from Weber carburetors and a new carb. It worked great for maybe 10 minutes. Started fine, no hesitation and could be restarted but it did not last.

So last week in desperation I decided That it sure wouldn’t hurt to swap out the distributor with my old and worn 009 and it worked on the first try. Dialed in the timing with the light and it has been good since. No overheating problems so far but have not been on any real long trips with it yet. The only issue I seem to have is that the throttle sticks open when the engine is warm. A tap to the carb linkage gets it back down but comes back with the next press of the pedal. This may be a nut that is just a little too tight and I will address that tomorrow. It is surprising how much fun it is to drive when it works well.

As for the adjustment of the idle mixture screw, I drilled out a small knurled piece of aluminum and pressed the adjusting screw into it. It works perfectly. I can now easily adjust it with my fingers.

Enough for now, time for dinner.


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