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Hot engine and difficult to tune

The original 30PICT-1 carburettor in my 1966 1300 was leaking from the throttle shaft. It hasn't been running right for quite some time, and was getting low MPG. Now my 1303 is out of action, I need to get this sorted!

The replacement 30PICT-1 carburettor was pulled from a 1972ish Beetle I found in a local scrapyard. The carb was fully dismantled and thoroughly cleaned and rebuilt with a new kit. I used the 6v pilot jet, main jet and air correction jet from my '66's original carb as the ones in the replacement were for a 1500 (I think). Original had

0125 main jet and 125Z air correction jet, which tally with the specs in my manual.

I also changed the oil, cleaned and adjusted the plugs and points to the correct gaps and set the timing (static timing 7.5 BTDC).

As per

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(thanks Rob and Dave!) I adjusted the volume control screw all the way in, then 2.5 turns out. Car starts no problem and idles okay with a medium/fast idle. Once everything has warmed up, turn the screw in until the engine note drops... except... it doesn't. Sometimes turning the screw all the way in and the car runs, sometimes it stalls. There is a very slight drop, but not much at all and then proceeds to speed up again.

I managed to find a setting that the car runs "okay" at, although the performance - although not bad - isn't as good on acceleration and top speed as I know the car can be. Also the rear apron got really rather hot. Not too hot to touch, but hotter than it has before.

Any ideas on what could be wrong, or how to diagnose?

-- Howard Rose

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1966 Volkswagen 1300 Deluxe 1975 Volkswagen 1303S 1962 Austin Mini Seven
Reply to
Howard Rose
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1st thing to check if its running hot, is timing and mixture.

Too advanced on the timing or too lean on the mixture will make it run hot.

Try ajusting the carb a bit richer if you havent changed you timing.

Rich

Reply to
tricky

manifold air leak causing lean condition, poor response to adjustment, and overheating?

Jan

Reply to
Jan

I haven't touched the manifold since I swapped carbs, and it wasn't running hot before. I have checked the bolts for tightness anyway, they are all fine.

However, today I did notice that the exhaust shows soot from the join between the silencer box and the tube that the tailpipe is mounted. It's 5 years old, so I'll pick up a new exhaust and put it on tomorrow.

My "test" run is 2.8 miles. I find that when cold the car runs relatively okay (needs fine tuning though). But after about 1.3 miles the top end performance (above about 45mph) drops and the car starts making "plip" sounds on deceleration. That is of course, when the car has become hot (rear valance is too hot).

The timing is spot on, set as I have always done with a static lamp.

I've ordered a new volume control screw, hopefully that may make some difference!

-- Howard Rose

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1966 Volkswagen 1300 Deluxe 1975 Volkswagen 1303S 1962 Austin Mini Seven
Reply to
Howard Rose

How's the valve clearance?

Jan

Reply to
Jan

Sounds lean.

Sure you have not overseen any other factor contributing to running warm, like debris in the fan? Just asking..

Fuel pump and/or filter, clean and A ok?

Stuck oil bypass checkvalve?

J.

Reply to
Berg

Make sure the carb mount to manifold surface is flat with no air leaks at that point.

Reply to
Freddy Badgett

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