60 replies to this topic

[Marc13]

If you can't lay your hands on a compression tester easily, you could spend the time investigating the carb.

 

Did you get the dashpot off?

 

Was there any sign of of all that excess oil?

 

Identify the float chamber breather: the hose that isn't from the fuel pump or the 10mm bore one connected to the engine breathers.

 

If you blow down that, in to the carb, fuel should emerge from the jet (dashpot & piston out). Look at the bottom of the ramp to the engine side & you'll see a small hole, that is the choke jet. You can repeat your blow test with the choke in & out. Stick a finger over the main jet to block it - obvs fuel should not emerge from the choke jet is the choke is closed.

Struggling to find the choke jet! I think I'm getting lost at " Look at the bottom of the ramp to the engine side & you'll see a small hole, that is the choke jet".

Probably really obvious once you know where it is, but I haven't a clue....

[Retro_10s]

You're looking for something like this (indicated with a cocktail stick). I took this photo of my HIF38, but I believe the HIF44 should be mostly the same internally.

[Marc13]

i thought that was the main jet? If that is the choke jet, then were is the main jet (that I have to put my finger over)?

[Ethel]

I'm wondering if I'm "misremembering" just had a look at spare carb, it has those also but they don't look like the jet.

 

 

 

My spare carb is a New old stock Hif E. That's the last type with electronic choke & I don't remember ports in your photo from my carb on the car, but it's  hard to see how they won't be choke related given the location. 

 

It did lead me to find this ignoring the overly complicated stepper motor, the diagrams illustrate the hif choke pretty much as I remember.

[Ethel]

The main jet is where the needle goes in, the brass & aluminium "bullseye" smack in the middle of the bridge.

 

 

Of course, it'll  be the one you can make petrol come out of when the choke's open, if you look at it that way round   

 

 

....I actually think it's the one not being pointed at as mine seems to have a much smaller drilling inside. 

[Marc13]

so step one take the dash pot off.

 

step 2 - blow down the breather pipe and see if fuel comes out of the 'bulls eye - middle of the bridge' main jet? without the choke being pulled out?

 

step 3 - cover the main jet and blow down the breather pipe  and see if any fuel comes out the choke jet? without the choke being pulled out?

 

Step 4 - repeat step 3, but this time pull the choke out fully?

[Retro_10s]

...I actually think it's the one not being pointed at as mine seems to have a much smaller drilling inside.

Mine's bigger than yourrrrrs

Could well be because the one I have here is an HIF38.

Actually I've just tried blowing through the breather with the choke open,... And the hole that air is coming through is actually after the throttle butterfly!

P.s. I fear my hif38 may confuse things now, so I'll keep schtum. :)

Edited by Retro_10s, 10 October 2022 - 05:11 PM.

[Ethel]

This could be taking on more importance than it deserves: It looks like Marc's car could be over fuelling. Dodgy choke seals are a possible cause of that. This is a quick and easy test that'll show if the choke isn't shutting off, but won't definitely say it's definitely not the cause of rich running.

 

It is higher pressure in the float chamber than over the jets that causes fuel to flow through them. Blowing in to the float chamber simulates that & will show there's fuel in the float chamber & the jets aren't blocked - or in the case of the choke that it is when it should be. It doesn't really matter where the fuel emerges, we just want to know it the seals are letting it by when they shouldn't.

 

Different again, but the idea is the same:

 

 

 

choke assembly at 38 minutes:

 

[Marc13]

Hi just back from holiday. Done the jet test.
1) main jet with no choke - fuel came out when blowing the breather pipe.
2) main jet with choke out fully. Same result, fuel came out the main jet
3) covered main jet, no choke, fuel did NOT come out the choke jet.
4) covered main jet, full choke out, fuel came out the choke jet.

Is this all the correct results?

Going to take the car for a good run, and see if the same plugs show the sam results in the same order...

The carb jet is set approx 1 to 2mm below the bridge by the way

[Marc13]

So I have been for a decent run in the mini and checked the plugs again.

the 1st two photos are of plug 1 (far left), then 1 of plug 2, 1 of plug 3, and the last photo is of plug 4 (far right).

As you can see, the situation is the same as before. Plug 1 is the lightest colour by a long way, 2 is a little darker, 3 is darker still and 4 is much darker (than 1).

Any thoughts - I assume my findings from the carb jet tests are fine?

 

 

[Marc13]

any thoughts after my last posts?

[ACDodd]

Set your plug gaps correctly is a good start that looks much too big

Ac

Edited by ACDodd, 31 October 2022 - 07:23 PM.

[Marc13]

what should the gap be?

[sonscar]

at this point...buy a manual.It is full of useful information.I am being serious,Steve..

[ACDodd]

What ignition system do you have?

Ac