Difficult cold start and running rough

Need help debugging the problem. The engine is an 1880 with a 34PICT carb, standard dizzy with electronic ignition
On most cold mornings, it is difficult to start. I can tell its firing on one or maybe two cylinders so hardly cranking. I have to floor the pedal to keep it going then after a minute, the other cylinders start kicking in and the revs will pick up. It will take maybe 15 minutes by the time it is running smoothly
I replaced the spark plugs already. Could it be a bad coil or bad HT leads?

Is this something that has just started happening or has it been going on for a while now?

R 🙂

Going on for a while

I have limited knowledge but - Have you checked your plugs again? In aviation an engine sometimes ran rough prior to take off. We used to run it up to 2000 rpm then lean out the carb - this causes the cylinder head to heat up and burn off crap on the plug. You are doing a similar thing by flooring it and warming it up.The engine would then run smoothly. I would check if your plugs are fouled. If so it would point to a carb mixture and/or timing issue.

It could well be the issue because its running very rich. Mixture screw is jammed so I can't adjust it but I do have a near new 34PICT which I was planning to use. Will do that first and see
Thanks

By they way, is this was the problem, why would it happen only in the morning?

Hmmmmm sounds like your ignition timing is way to advanced. You do know that the marks on the crank pulley are 7.5deg and 10deg, neither is Top dead centre.

Thanks Mate, yes I am aware of what the marks represents
I replaced the one on the left with the one on the right (near new 34PICT) and its running much better now. However I am getting a small amount of backfire at idle when the engine is still warming up. Running too lean?

karmannghia60 wrote:Thanks Mate, yes I am aware of what the marks represents
I replaced the one on the left with the one on the right (near new 34PICT) and its running much better now. However I am getting a small amount of backfire at idle when the engine is still warming up. Running too lean?

Hi
the carby on the Left has a piece missing o n the top shaft

the carby on The Right has it...

I don't think Your automatic choke was working...

turn the mixture screw in until the engine dies a bit [revs reduced] and unscrew about 1/2 a turn... see how it goes..

have You checked the choke flap?? choke adjustment?

when starting the engine...
You should push the accelerator to floor once..
then take Your foot off the pedal..
this operates the automatic choke....
then turn the key....

it should start and idle fairly high depending on the choke adjustment ...

what distributor are you using??

LEE

Thanks Lee
You are right about the missing part, I never noticed before!
i am running a standard vacuum advanced dizzy
The way I adjusted the mixture is different from what you described. I usually turn the screw till I get to the highest revs them turn it in 1/4 to 1/2 turn

what idle jet are you running for your bigger donk?

55 or 60 might not cut it for 1880cc. Mind you i get that kinda rubbish running on my 1600, but is a POS 34 pict 4 that is VERY well aged.

karmannghia60 wrote:Thanks Lee
You are right about the missing part, I never noticed before!
i am running a standard vacuum advanced dizzy
The way I adjusted the mixture is different from what you described. I usually turn the screw till I get to the highest revs them turn it in 1/4 to 1/2 turn

OK

Yes
screw the screw in until You hear the slightest rev drop
[hesitation] and screw it out about 1/2 a turn...

engine must be hot to do this...

its probably running too rich...

cheers

LEE

PS: I always give it another 1/4 turn out to be sure...
a lean running beetle isn't good...

I would bet that the mainjet would want to be bigger if you are running a larger 1880 engine too.