[Jack jr]

G'day I just fitted a 4k carby on my Suzuki Sierra, I machined an adaptor out of bronze to keep the stock carby hat and made a bracket out of angle iron for the throttle cable. The choke is a stop cable from a boat.
Cheers Jack.

[barbender]

Any pics of the modifications Jack ?

[Jack jr]

G'day Barbender i will take some photos and when i find out how to post photos on this site i with put them up.
cheers Jack.

[Jack jr]

I machined a ring out of bronze to 2 1/2 inch id, put a lip on the outside that was a tight fit in the carby hat, then i glued it in with fixtec 190, i cut the threaded end off a clutch cable and used that as the stud to hold the hat down.
the throttle cable bracket is made out of a piece of angle iron i cut down.
cheers Jack.

[Jack jr]

Forgot to add, I fitted a stronger return spring to the throttle and when you remove the spacer there is a cutout in it, I filled it with rtv then cut it smooth with a Razer Blade.
Cheers Jack

[Jack jr]

Gday everyone just an update i pulled the corolla jet out which was 170 and fitted the original sierra jet which is 105, just to see if i can get better economy.
cheers Jack.

[accblam]

Jack jr wrote:

Gday everyone just an update i pulled the corolla jet out which was 170 and fitted the original sierra jet which is 105, just to see if i can get better economy.
cheers Jack.

How do you go with the Sierra Jet over the Corolla Jet?
Asking because a cant seem to get mine to run lean enough!

[Jack jr]

G'day what makes you think it is running rich?
I went back to the corolla jet as the car seamed to go better,
At the moment I have for memory a 105 primery and a 170 main
Cheers Jack.

[accblam]

Jack jr wrote:

G'day what makes you think it is running rich?
I went back to the corolla jet as the car seamed to go better,
At the moment I have for memory a 105 primery and a 170 main
Cheers Jack.

I had a mate that has some clear spark plug try to tune the car after puting the 4k carb on, and he said he couldn't get it to lean out enough before cutting the fuel altogether.
one of my main concerns is that the car dosent have the power to climb any incline on the highway.

[Jack jr]

Do you know what size jet are In it currently? And when you say you mate couldn't get it to run lean enough before shutting the fuel off, what was he adjusting? Was it the idle screw or was he putting smaller jets it it?
Cheers Jack.

[accblam]

Jack jr wrote:

Do you know what size jet are In it currently? And when you say you mate couldn't get it to run lean enough before shutting the fuel off, what was he adjusting? Was it the idle screw or was he putting smaller jets it it?
Cheers Jack.

Have no idea of the jet sizes.

He was adjusting the mixture screw. Idle screw and adjusting the timing. The mixture screw he would keep turning in trying to lean the mixture and would bottom the screw starving the carburator.

[accblam]

not sure of the jet sizes.
he was adjusting the screw at the base of the carb on the manifold side. he turned it inward to try to lean the mix out but would bottom out an stall

[Jack jr]

That's only the idle jet and only really affects fuel mix at idle. If you could find out the jet size that would be good.
Did the car go well with the original carby? If it did it would narrow down what the lack of power problem could be.
Cheers Jack.

[accblam]

Firstly thanks Jack for your time in responding.

Now you mention how it was running on the old carby, i dont think it is the carby now. The reason I put the 4K on was I thought the carb needed a rebuild.

Having a look last night I noticed oil coming from the fuel pump, so that might be a start. Also on start up i have a liquid spitting from the exhaust putting soot on the ground.

[Jack jr]

Not a worry Accblam.
Firstly i wouldn't worry about the liquid spitting out the exhaust as mine does that and its just condensation.
is there a blockage in the air intake/filter/snorkel as that would cause it to run rich and have no power?
Cheers Jack.

[Jack jr]

G'day just an update i have gore back to the standard sierra jets and it is running well.
Cheers Jack.

[accblam]

Jack Jr,
I have changed the fuel pump. The car goes better now off the mark but stills struggles to climb hills on the highway.
What was your reasoning for going back to the sierra jets, and is it a hard job as i still have the old carby here?

Adrian

[Jack jr]

the reason i wend back to the sierra jets is i made up an exhaust that exited under the drivers door and went for a drive every time i accelerated hard there was a puff of black smoke.

No if you can change a fuel pump you can change the jets, all you do is disconnect the small steel rod that operates the choke butterfly then remove the Philips head screws that hold the top down,
be careful not to tear the gasket under the top, and be careful the float and needle don't fall off from under the top of the carby then you will see a jet facing up from the bottom that is the secondary,
you then have to remove the bung on the side of the float bowl and poke a screwdriver in to undo the primery jet which is in the wall of the float bowl.

As for it struggling on hills what do you mean? struggles to pull 1st gear up hill or struggles to pull 4th gear up hill.
if any of this is confusing please say and i will try to clear it up.
Cheers Jack.

[accblam]

Jack jr wrote:

the reason i wend back to the sierra jets is i made up an exhaust that exited under the drivers door and went for a drive every time i accelerated hard there was a puff of black smoke.

No if you can change a fuel pump you can change the jets, all you do is disconnect the small steel rod that operates the choke butterfly then remove the Philips head screws that hold the top down,
be careful not to tear the gasket under the top, and be careful the float and needle don't fall off from under the top of the carby then you will see a jet facing up from the bottom that is the secondary,
you then have to remove the bung on the side of the float bowl and poke a screwdriver in to undo the primery jet which is in the wall of the float bowl.

As for it struggling on hills what do you mean? struggles to pull 1st gear up hill or struggles to pull 4th gear up hill.
if any of this is confusing please say and i will try to clear it up.
Cheers Jack.

Driving on the high way I can get the car to do 100km/h, (Just) but happens at any speed. As soon as I get to any kind of incline the car just doesn’t have any the power to continue up the hill. I overcome it by dropping it back a gear before the hill and keep the revs high. On bigger hills I need to drop it back another gear before the revs drop at all.

I also have a really steep hill coming out of my estate which I need to over rev in 1st gear, then change gear quickly. The car then struggles its way up.
If I get the gear change wrong I then have to go back to first gear.

To expand on my original thoughts of the car running rich is that it seems to be heavy on fuel. so that along with the lack of power made me think it’s over fueling.

This is my first Sierra so could this be normal behaviour?

[Jack jr]

G'day what size tyres are you running? That makes a big difference in how the car goes on the highway?
Cheers Jack jr

[accblam]

Jack jr wrote:

G'day what size tyres are you running? That makes a big difference in how the car goes on the highway?
Cheers Jack jr

I'm have 31's on it.

I've been away and my daughter was driving it but now the car revs upwards of 6000rpm so the fuel mixture can wait until i fix this problem now.

[Jack jr]

G'day if you have 31s and no gearing the car will be way under geared. My Sierra has 28s at the moment and you have to give it a bit of a rev to get going and it runs out of power on the hills quickly, your speedo will also be reading less then the car is actually doing.
As for it reving a 6000rpm could one of the throats of the carby be jammed open?
Cheers Jack jr

[Jack jr]

More pictures.

[MrRocky]

Does it open fully with that bracket ?
Initially my bracket looked the same but had to move it away from the carb and lower the cable mount so it would open fully.

[Jack jr]

G'day MrRocky it can open flat out.
Cheers Jack jr

[Jack jr]

Another update I am running the corrolla high speed jet, I don't know the L/100 but the car seams to pull very hard at low revs up hill compared to the sierra jets I hardly rev it over 3500 even shifting up hill.
Cheers Jack jr