Cold start= great/Hot start= :(

[RCN]

1990, 1.9L DG, automatic, Petrol.
I replaced the engine with a "new" rebuilt in February. With that i never had issues starting her up hot or cold.

The new engine has the "old" carb, coil, amp, but the "new" dizzy, fuel pump, HT leads and plugs (which were cleaned gapped and looked brand new anyways)

The problem: when i start her up when cold she fires up straight away and no issues. After driving for a while and it's hot when i try to restart it cranks for 5 seconds or sometimes more.

The "old" engine never did this, it would fire at the touch of the key. It sounds like the carb is empty of fuel and the float bowl is having to be refilled. Like i said, it has the original carb and never did this before. I'm thinking that i should simply put in a fuel stop vavle between the carb and pump to keep a fuel supply always there. Or am i missing something obvious?
Cheers

[CovKid]

I think most would recommend fitting an electric pump as its simpler to do and you remove the need to wait a while for fuel to come through the way you do with a manual pump. It does sound though, as if the fault lies elsewhere. Might be a coil issue.

[RCN]

I thought about the coil, but the problem only occurs when cranking. Once she's running, she's as smooth and anything and no issues that make me think electrical.
What do you need to do to install an electric pump? I'm not great on electrics, because I'm red/green coulour blind, and I've had some shocking results because of that

[CovKid]

First of all it may be worth removing rotor arm temporarily, pulling the fuel pipe off carb and get someone to crank the engine over. See if the fuel being pumped looks sufficient at cranking speed. If it is, you can probably rule it out. Sticking float chamber valve when hot? I think you need to get the unknowns out of the equation to help you pinpoint whats causing it.

Seems odd that it'll start from cold when theres a greater chance of fuel running back to the tank and/or drier fuel line but yet when warm, where you'd assume fuel system is primed, that you get this issue. Usually, elecrics tend to be more prone to performing below par when they're hot. It could be over-fuelling or fuel starvation. You need to leave throttle pedal well alone when starting these from hot or it'll flood very easily.

Its also worth bearing in mind that from cold the mixture is always richer by default (and any potential idle jet problems masked) wheras its a lot leaner at idle when warmed up.

[kevtherev]

There is a method for starting a hot VW WBX engine... in the manual
Jus' sayin'

[Arripay]

There is a method for starting a hot VW WBX engine... in the manual
Jus' sayin'

Haha, thanks for that, a classic case of RTFM!
Mine starts with a little waggle of the key when cold but needs a right old crank when hot, will try foot to the floor as the manual suggests

[RCN]

So will I.
Cheers