30 pict 1 on dp 1600- bogs down and pops when cold

[BenderTheRobot]

When the engine has been ran for awhile, (hot) it runs great, happily gets up to highway speeds and revs very nicely. It runs good and revs good when cold too, but when I put a load on the engine it bogs down (basically no acceleration) and pops a little bit. It mainly happens in 2nd gear at lower rpms.

I did follow the procedure for setting the idle mixture. I believe you start 2.5 turns out, then turn in until the idle drops, then back out to achieve max idle again. All while hot and the choke is completely off.

Engine specs:
Vw 1600 dp
30 pict 1 carb- 125 main, 60 idle, 115 air (I know it is a little small, but it should work) I also have a 130 main I put in and when I did that it had almost no power.
Pertronix coil and 009 electronic ignition, timing set to 30 degrees total advance

Am I running too rich or too lean? I am 3000 ft above sea level if that helps any.
Do I need to adjust my electric choke? I know a lot of people who have gotten rid of electric chokes due to problems like this.

[VW_Jimbo]

Pops out the carb or the muffler? Typically too lean out the carb and too rich when out the muffler.
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[oprn]

I am running a 30PICT-2 WITH THE MATCHING VW DISTRIBUTOR on my 1641 SP. Runs really sweet at all times under all conditions. I put a wide band on just to see where the mixtures were... guess what? It's squarely in the 13's all around! VW seems to have got it right.

I am thinking you have a vacuum leak.
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Our cars get old, we get old but driving an old VW never gets old!

[BenderTheRobot]

What is the best way to check for a vacuum leak? If I have a vacuum leak wouldn’t it pop out of the carb due to more air? I guess it could explain it due to thermal expansion.

[BenderTheRobot]

Also it does pop out of the exhaust, but when I tried putting a bigger main jet in it was popping from the carb???

[oprn]

Spray something combustible around all the connections on the intake. The engine will tell you if there is a leak.

I wouldn't rule out spark scatter either from sloppy or worn distributor parts. Could have cross firing on the cap too.

I just had my timing light on my Buddy's Buggy. Spark was steady at idle but the higher I rev-ed it the more unstable it was. One of those cheap no-brand electronic distributors. You know the one, white cap and module on the side, $65 I think I saw them advertised a few years back.

If you seriously want to know what the mixture is beg borrow or steal a wide band and weld a bung in your exhaust.
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Our cars get old, we get old but driving an old VW never gets old!

[oprn]

Hang on a minute! Is this a type 3 engine that you put a single carb on? Lets see a picture of the conversion please! I want to know what you are doing for intake manifold heat.
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Our cars get old, we get old but driving an old VW never gets old!

[VW_Jimbo]

[BenderTheRobot]

No, not a t3. Would be interesting to see though. I will try the starting fluid. Thanks!

[mikedjames]

Carburettor is a bit small for a 1600 DP. It is usually a 34PICT-3.

Was it once an SP engine and did you keep the same distributor? The distributor timing curves are different..
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Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[oprn]

The answer is in his first post.
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Our cars get old, we get old but driving an old VW never gets old!