3g dual carb auto choke issue

teg98 · Post by **teg98** » Sun Mar 09, 2014 8:04 pm

Recently joined this excellent forum.
Looking for some help with the auto choke on my dual carb 3rd gen.
almost as soon as I start the car it will rev to just over 2k rpm is that normal?
Also the auto choke seems to stay on way to long even one the engine is fully warm.
I have a 4g civic 1.4 dual carb manual choke and I can push the choke level all the way in very quickly.
my thoughts are maybe to convert it to manual choke. Has anyone done this before?
Any ideas will be gratefully received.

'92 Si VTEC · Post by **jjmartin349571** » Sun Mar 09, 2014 8:24 pm

I've no experience with a honda autochoke, but the autochoke on my VW Golf has coolant running through it. It's common for the coolant pipes to get blocked causing the autochoke to stay on too long - if the setup on your Honda is the same them maybe check you're getting coolant flowing through the choke housing properly.

As for the revs, my Golf is designed to rev to 2k rpm on cold start for about 3-5s, then it drops down to the fast idle controlled by the waxstat. Provided your Prelude is only revving up for a few seconds I'd say that it's normal.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Mar 09, 2014 10:41 pm

Looked up in a Chilton manual I got recently from h10ndr and Jj's right, 3g's use coolant to heat the choke. Surprised me, because Nissan's of that era used an electric heater on bi-metallic strip...

A couple of pages from the manual that might help:

(posted in reverse order, sorry - on the phone so it's a nightmare to cut and paste to swap them round now

)

Post by **RattyMcClelland** » Sun Mar 09, 2014 10:45 pm

My ex prelude carb usually revved at 2k on the autochoke but would sit normal after a few miles. Cold weather was a different story. I could sometimes do a full 20mile journey on the autochoke below minus.

teg98 · Post by **teg98** » Sun Mar 09, 2014 10:55 pm

RattyMcClelland wrote:My ex prelude carb usually revved at 2k on the autochoke but would sit normal after a few miles. Cold weather was a different story. I could sometimes do a full 20mile journey on the autochoke below minus.

Yeah its been pretty cold and similar mileage would still be on auto choke i have to fix this.

teg98 · Post by **teg98** » Sun Mar 09, 2014 10:57 pm

Thanlks wurly i will have a read through that lot and see what i can find. Would still rather convert it to manual choke, then im in control. MPG is being hit atm.