32/36 Weber Bogs Down At Full Throttle

[crdiscoverer]

Hi mates,

 

I installed a brand new 32/36 Weber on my KE30 Rolla. It is supposedly a 3k/4k kit so I guess it is already properly set-up for the application, or at least close to. I took it for a test drive the other day and everything is great except when applying full throttle. The engine bogs down (seems to be choking) and all power is lost. I checked for vacuum leaks and there are none. It doesn't matter if I accelerate smoothly or if I step on it, the results are the same. It looks like it's at the moment the secondary throttle valve opens.

 

Being basically a noob in regards to carb tuning and such, I wonder what could it be? Lean/rich mixture? Vacuum advance not working properly? I still haven't connected the electric choke, could that be it?

 

Thanks! Pictures to follow.

[mhmills]

Was this one of those Ebay 32/36 Webers?

[Twinky]

secondary jets could be too small. Does it actually slow down or splutter? If you feel the loss of accelaration then the jet could be running too lean.

[bruce]

If the engine is all warmed up it shouldn't be the choke.

Did the kit say what size the primary and secondary jets were?

[altezzaclub]

Google the carb- there is a lot about it on places like Alfa Romeo forums or Fiat, all the continental cars that ued them.

 

You will need to either get an oxygen meter to check it or learn how to tell lean from rich when it dies.

 

You'll need to learn about the idle jets, (up to nearly 3000rpm) the main fuel jets, (the rest of the midrange to top) and the air corrector jets. (they stop the top revs being too rich)

 

Check EvanG's topic about his Weber, I posted a reference in there to a good tuning page I found one time.

[Evan G]

vac or mechanical secs?

 

bogs down & loses all power = lean

 

bogs down and slowy picks up then its fine = rich

 

 

 

i also had a problem of it would lose all power at 3000rpm +

 

turned out the coil was shorting out to the postive terminal

 

edit http://www.vw-resource.com/jets.html

 

 

have a GOOD read through that, explains how everything works and how to work out the basic tuning/diagnostic

Edited March 1, 2011 by Evan G

[CA-ROLLA]

its leaning out

[JJT036]

32/36s are probably the most common Carby Conversions on 3K/4K Engines, but one problem I've found, is that the 32/36 FLOODS the engine out, therefore losing and lacking your Precious K-Engine'd Power. :)

 

Your best option is to just 3/4 Throttle it for maximum power. OR, get yourself a 28/32, or if you've got a Big Wallet to waste on Petrol, a 28/36 from a Cortina. :)

Edited March 2, 2011 by ewt

[crdiscoverer]

Was this one of those Ebay 32/36 Webers?

 

It's a RedLine Weber kit. I bought it from Amazon and it's supposedly already jetted for stock-ish 3k/4k applications. This is it:

 

http://www.amazon.com/gp/product/B001G642PG

 

secondary jets could be too small. Does it actually slow down or splutter? If you feel the loss of accelaration then the jet could be running too lean.

 

It loses all acceleration and the engine gets very rough/splutters, it doesn't actually slow down; It's more like it stops accelerating, low or high rpms it's the same thing.

 

If the engine is all warmed up it shouldn't be the choke.

Did the kit say what size the primary and secondary jets were?

 

No idea. The manual wasn't very specific. Here is their website, I've been looking:

 

http://www.redlineweber.com/carb-kits/auto/toyota/

 

It's the K662 kit.

[crdiscoverer]

vac or mechanical secs?

 

bogs down & loses all power = lean

 

bogs down and slowy picks up then its fine = rich

 

I was asked the same question by a couple of guys: "Does it pick up after a few seconds?". The answer is: "Nope". For as long as I keep the gas floored, the engine never delivers power.

 

I will try to shoot a video for you. Shouldn't be that hard and the change in engine note will be very noticeable.

 

Nobody mentioned this could be a timing issue so I will assume it's basically incorrect mixture, right?

Edited March 2, 2011 by crdiscoverer

[crdiscoverer]

Turns out the electric choke (while being disconnected) interfered with the adequate airflow at full throttle. I finally connected it and tuned the high idle speed, and everything is now normal. Car keeps pulling strong at full throttle. I've found two things though:

 

1. Car doesn't seem to be faster than before (though it is way noisier at full throttle).

2. I've been using it for a few days and the fuel mileage tanked.

 

I guess it's all a matter of fine tuning the carb now. I will take it to a shop with an emissions testing equipment to set it up properly.

 

Some pictures during the install (sorry about the quality, it was dark and I only had my cell phone at hand):

 

 

 

It really stands out between all that dirt! I know, I know. I need to clean my engine bay.

Edited March 8, 2011 by crdiscoverer

[Twinky]

If you really want to make use of the webber carby then I would suggest a mild cam and ported head with extractors.

Slapping a webber on a stock 4k motor is a bit excessive, if you are worried about fuel consumption you shouldn't have gone webbers!

[crdiscoverer]

No, I'm not worried about fuel consumption. This is not my daily driver so it can use whatever fuel it wants. :happy:

 

So far I haven't had problems with an overly rich mixture or anything. It performs just as the stock carb, but slightly better. Specially the throttle response, which is faster/more direct.

 

I know I need to get me a new set of cams. I want the Tighe 112, but it's impossible to get it here. The only option would be getting one imported from OZ, so if you know about somebody who's selling one, let me know.

 

The extractors are also planned for the near future.

[altezzaclub]

Where are you Eric??

 

We could get a cam/followers cut here and mailed over. Tighe might do it direct, they must deal with people overseas, or a club member. Can you get extractors made locally, or do you need those from Aussie too?

 

You will need a bit of head work to take advantage of the other changes. A skim to raise compression, a check to make sure the ports all match...

[Evan G]

ill be flipping the carby 180 degrees so that the fuel in is facing the front of the car. so on hard lunches the fuel doesnt move away from the jets and run empty.