Warm up problems

I having trouble with my 1600dp from start up. It is un-drivable for 15 minutes until it warms up. In this 15 minute period, as soon as you touch the accelerator it stalls (when the choke opens). It will idle when the choke is on but when the choke opens it stalls and I have to keep restarting it until its warm. It drives really well after that.

Ive checked the choke operation and it seems fine. It takes about 5 mins to open up. I replaced the manifold so its not the heat risers. I have also checked for leaks. Played with the fuel pump setting on the carb to. The carb is a new Bocar 34/3 and is adjusted correctly. Like I said it runs sweet when warm.

I have noticed that the bottom of the carb and around the inlet flange is ice cold to touch.
When I got the car the oil bath filter had the warm air hose/flap portion of it pulled off.

I am thinking about reconnecting the warm air hose and oil bath end piece? How it the flap operated?

It's a later AS stamped 1600dp with an oval shaped oil bath..

I am about ready to drive it off a cliff😬

I don't think the connections on the oil bath would make much difference, I have the same problems with mt 1300SP when it is really cold, honestly you just need to sit and warm it up for 5 minutes before driving (when it allows) I think it really is just a bug bear of having an old car...

Brad, the preheat flap was operated a few different ways over the years
70 and earlier theres a cable down to the thermostat, 71 had its own invidual thermostat and 72 on works on vacuum from the inlet manifold and controlled by a thermostic valve in the top of the air cleaners in 72 oil baths or bottom of the 73 on plastic style paper element ones

ive never come across a vac one which is what yours should have that still works.
after 35+ years the diaphrams split and all they do then is create a vac leak and worse running, if thats not the case then its the thermstatic valve that doesnt work

also you need the lower stove pipe ducting for it to work as well
and not to many bugs still have this, seems to be mandatory to chuck it out when a new exhaust is fitted

are you back witha stock muffler now?
there the best for preheat in colder weather

Yeah Joel the stock exhaust is back on.
I was talking to an old VW mechanic this morning and he was saying that in the late 60's Vw Germany sent out a bulletin to Australian workshops to disconnect the pre heat hose and the counter weighted flat and the thermostat and flap. Somthing about the stovepipe filling up with dust and stuffing up the air cleaner.

I would really like to get some heated air into the carb during warm up but it sounds like more trouble than its worth. Try finding a good working thermostat, forget it!.

When I had my buggy in Canberra over a couple of winters, I used to be unable to ever get the engine running warmly, Canberra being so b*%&^$ cold and the engine hanging out in the wind rather than in a warm engine bay.

As is mostly that case there was no thermostat system in place. Come to think of that, I've never seen a thermostat on a Beetle engine.

What I did was to fit a piece of cardboard air hose from the engine behind the engine cooling tin, to the aircleaner and then the carburettor.

I fitted an old tin can, with both ends removed to the end inside the engine tinware and wired it in place.

All of the engine air came from that source. Within minutes the engine ran well as all of the inlet air was prewarmed.

That was probably a bit drastic, but it worked in that very cold climate.

I'd suggest a reconnection of the prewarmed air hose as the only source of engine air.

shaihulud wrote:As is mostly that case there was no thermostat system in place. Come to think of that, I've never seen a thermostat on a Beetle engine.

😉

mine was dead when i got the bug but i was so lucky my old boss still had a NOS thermostat from back in his dealership days
doesnt make a huge difference in drivability, definately noticeable but the real improvement is in fuel economy

shaihulud wrote:When I had my buggy in Canberra over a couple of winters, I used to be unable to ever get the engine running warmly, Canberra being so b*%&^$ cold and the engine hanging out in the wind rather than in a warm engine bay.

As is mostly that case there was no thermostat system in place. Come to think of that, I've never seen a thermostat on a Beetle engine.

What I did was to fit a piece of cardboard air hose from the engine behind the engine cooling tin, to the aircleaner and then the carburettor.

I fitted an old tin can, with both ends removed to the end inside the engine tinware and wired it in place.

All of the engine air came from that source. Within minutes the engine ran well as all of the inlet air was prewarmed.

That was probably a bit drastic, but it worked in that very cold climate.

I'd suggest a reconnection of the prewarmed air hose as the only source of engine air.

Thats ghetto as mate, I am impressed!

I hooked up a temporary solution for carb warm air today. I connected the cardboard tube to the air cleaner and to the upper rhs heater box/exchanger ( usually where the rhs dog house outlet goes to). I don't have the main heater boxes connected for cabin heat, just J tubes so the small upper heat exchanger sits right beside where the original stove pipe piece would usually sit (I don't have the stove pipe either).

I wired the preheat/thermostat flat open until I can find a new thermostat as the one that I have is buggered. Its a real hard part to find hey.

I have not driven it like this but when it warms up a bit I will unhook the flap so its sucking air from the top.

I did drive it this arvo with just the counter weighted flap for the crankcase heat connected and it idles heaps better from cold.

I have treid a number of things even a thermal collar around the carburettor however been air cooled they just take longer to warm up I go out 10 minutes before heading out and get it started by the time I go its ready to go as well I suggest you do the same.

Pacman77 wrote:I have treid a number of things even a thermal collar around the carburettor however been air cooled they just take longer to warm up I go out 10 minutes before heading out and get it started by the time I go its ready to go as well I suggest you do the same.

Hi Pacman. Most of the VW's I have owned required the warm up ritual. Its not through a lack of patience but after reading a few manuals and such it was suggested that driving straight after start up is the best way to get to normal operating temp.

Since I started this thread I found a working 72 oil bath cleaner with the thermostat and vacuum operated preheat flap. I found a pre heat tin piece from Aircooled.net and installed both of them.

100% improvement. I can drive from start up with no problems. By the time the choke and the preheater flat disengage its warmed up and I barely notice the transition.
Its also suggested that you change the oil in the air cleaner more frequently as the preheater elbow sucks in a little more dust. All good!