4ze1 difficulty starting.

[Fluglehorn]

Hey guys,

Having issues with the 4ze1 carby in my 1991 trooper starting.

I have to crank the engine for a few minutes before it will eventually catch and run. Once run for a couple of mins it will idle perfectly fine by itself, never had any issue with it dying on me. It has started fine the past couple of winters and now it's an absolute pig.

It doesn't seem to make a difference whether the throttle is closed or open except when it starts to catch I need to give it the jandal to eventually start running.

I don't think it's a spark issue and I've recently replaced the spark plugs.

It feels like a fuel issue to me. I think mine has a mechanical pump, or at least I can't see one on my tank. Is there anything I can do to the pump short of replacing it, also are there any tricks to removing it without taking off the whole intake manifold/carb/distributor?

Any help appreciated, cheers.

[geeves]

Check your spark first

[Fluglehorn]

Thanks for that geeves. I managed to find a Haynes manual for the trooper and checked all my leads, coil and battery with a good multimeter and everything was looking within spec.

I've figured out what the issue is. It's an accelerator pump issue. Pre lockdown I would only have to pump the accelerator as I started the engine and it would be away. Now I have to pump it a couple of dozen times and start on 1/4 throttle to get her going. Think it's time for a carb kit.

Next order of business. Getting the right mixture. After trying to fix my auto choke and getting nowhere, I messed up my mixture settings in the process and now am get around 16L/100km when driving country roads at the moment when I was getting just under 15L/100km previously driving the same sort of roads.

Currently I've turned my mixture screw in until the engine starts to stumble and drop in rpm, then turned it out 1/2 a turn and adjusted the idle speed to 900rpm.

Is this the right way to go about adjusting the mixture as my exhaust still smells a lot like petrol even when I think I've leaned it out?

[geeves]

Plug colour is the best check Looking for a mid to light grey