Idle Problems

[Xon]

I will readily admit up front I know very little about carbys, so please go easy if I sound like a bit of a tard!

 

I have a KE35 with a 4k block and 3k head in it. It generally runs quite well, but it won't idle for crap. Generally it will idle ok for a few seconds (sometimes a minute or two), then will start to shake and miss a bit, and then just stall completely. Sometimes it will try and stall as soon as I engage the clutch when slowing down for lights etc, although if I just let the clutch out and roll start it, it will generally idle happily for a little while.

 

If I sit with my foot on the accelerator a bit (sitting at 1500+ rpm) it will sit quite happily indefinitely.

It's also missing a bit below 2000rpm SOMETIMES, but not all the time.

 

To me, this seems to be a vacuum leak or similar. While having a quick look over the carby, I noticed the nipple in the picture below with nothing attached to it. I assume this should have something going somewhere, or be blocked off. Anyone able to suggest where it should go?

 

[ke70dave]

id block that hole off first, carbies don't like air going in in anythign else than than through the airfilter. Just get a bit of vac hose on the thingo and put a screw in the free end to block it.

 

id start off with the basics to be honest. so you got a good base to start with.

 

-make sure no vacuum leaks (like that hole you might have found there) make sure all the bolts that hold the carby down are tight.

-get a can of carby cleaner, open the air filter, spray the crap out of the inside of the carby, start the car (it will take a bit...), and keep on spraying it in untill it looks brand new. you wil need to keep the engine running as the carby cleaner tries to kill it, bit tricky with one person, you can do it though.

-check your ignition timing, ignition points gap, general spark plug and lead condition.

[Xon]

Thanks Dave, I'll give all of those a shot once it stops raining.

 

I just threw a vacuum guage on in various places (the nipple in the pic above, as well as the main vacuum hose that goes to the dizzy etc), and got a reading of absolutely nothing. I assume this is a big problem!

[Xon]

ok I'm an idiot. Like I said I don't know much about carburetors. I was checking vacuum in the wrong spot.

It looks like spark plug number 4 has weak or no spark at idle, but it's otherwise fine.

[rian]

There should be a vacuum diagram on the underside of the bonnet I think? That tells you where all the hose go.

[B.L.Z.BUB]

Has this just started happening? It could need a service, plugs points and leads at least.

It could be your timing is out a bit. Vacuum leaks is the #1 on the list though.

I had a tiny hole in my intake manifold and caused so many headaches until it was diagnosed.

Have you made any changes to it (engine) lately?

 

You may just need to give the idle screw half a turn

Edited May 24, 2012 by B.L.Z.BUB

[Xon]

It's been happening for ages to varying degrees, seems to have gotten worse lately though. I'll have a good look for vacuum leaks, but I pulled the lead off spark plug #4 and the idle wasn't affected at all, so I'll check the gaps and maybe replace the leads in the morning.

[B.L.Z.BUB]

swap one lead for another and eliminate the leads before you buy new ones.

[Xon]

Yep, that was the plan for sure. Got a spare set of plugs sitting around to try too.

Edited May 24, 2012 by Xon

[B.L.Z.BUB]

Gap them to 0.8 and your points to 0.45 (ish)

 

If it doesnt work and you are getting weak spark at the plug still i'd be looking at your dizzy cap.

[Xon]

Cheers for the specs, fingers crossed it's something simple like wrong plug gap.

I replaced the dizzy cap not long ago so hopefully it's not that!

[Xon]

Looks like the dizzy is worn out and is retarding the timing too much. Points are ok, plugs are all ok, cyl 4 has plenty of compression, but the timing goes way out after a good throttle blip.

I'm wondering if it's worth going for an electronic replacement?

[ke70dave]

i consfused.

 

retarting timing too much?

 

you set the base timing with the vac pipe off around 8-10 BTDC at idle. done that yeah?

[Xon]

Yes Dave, but after giving it a good rev the timing goes way out as it comes back down to idle. It evens out, but often stalls before it comes good.

[springersrolla]

what carb are you running?? is it a pre pollution 3k or a 4k carb?? also check out about fuel solenoid, disengage it, and se if anything changes