Thread: RRC Running super rich

G`day ,

the choke will most likely be the disc type , it should only be on the left hand carb .

It meters fuel rather than air flow like most things , the disc has 3 or 4 holes of different sizes and as the disc rotates when the cable is pulled it opens the holes .

If it`s set up like a normal 3.5 , each carb feeds 4 cylinders so if you pull the plugs and find four dark and four not so much , it may be that only one carb is playing up .

i`m pressuming you checked the float levels when you cleaned them , and put the pistons the right way .

Ours has CDs and LPG as well , it was running very rich at one stage on petrol but i can remember what the problem was , i must have fixed it because it doesn`t blow black any more , i do remember it was nothing to do with jets or the choke .

Thanks Peter,

Admittedly, I checked the float bowls for dirt etc. but didn't check the float levels so that will be the next port of call. Interesting about the disc choke, haven't seen one like that before.

In terms of the pistons being around the right way, I've put them back in so the rectangular notch on the rubber diaphragm lines up with the recess in the housing, I'm assuming that is the right way around but if there's another way to easily tell I'll check that too.

In the fiddling I've done, it seems that the passenger side carb is running much richer than the drivers side (based both on the colourtune and lifting the piston slightly while running) but both have the same needle settings and I've balanced them as much as I can with a bit of hose to my ear.

More checks to be done!

Cheers,
Steve

Originally Posted by Mister_white_keys

Thanks Peter,

Admittedly, I checked the float bowls for dirt etc. but didn't check the float levels so that will be the next port of call. Interesting about the disc choke, haven't seen one like that before.

In terms of the pistons being around the right way, I've put them back in so the rectangular notch on the rubber diaphragm lines up with the recess in the housing, I'm assuming that is the right way around but if there's another way to easily tell I'll check that too.

In the fiddling I've done, it seems that the passenger side carb is running much richer than the drivers side (based both on the colourtune and lifting the piston slightly while running) but both have the same needle settings and I've balanced them as much as I can with a bit of hose to my ear.

More checks to be done!

Cheers,
Steve

G`day Steve ,

as long as the same thing was done with piston and diaphragm they must be the right way .


You may know but the float level is 16mm to 17mm from the gasket surface to the float top (upside down ) .

Clockwise is rich .

The start point for the needle is usually , needle shoulder flush with piston face .

If the CD 175 carbs are from a 3.5 RR and have the original needles , should be one of these .

B2AS

B1DW

B1EJ

B1FH

They are all top adjust type .

I guess you had a look at the tapper of the needles for obvious wear .

Back in the early 70s a mate had what we called a Mini panel van , maybe it wasn`t , great little car though , nothing to do a 130km round trip to go to the drive in .

Cheers

Thanks for the extra info, that'll be most helpful. I'm hoping to get out into the shed and have a play with them in the next day or so.

I've got a 1964 mini van and love it dearly, it's travelled up and down the east coast of Australia as well as competed in various forms of club motorsport including motorkhana, autocross and hillclimb. I bought it when I was 17 and rebuilt the whole car over a few years, it's a magical little car that always puts a smile on my face

Alright, update time.

I've taken the passenger side carb off and checked the float level which is bang on at about 17mm. While having a look though I think I may have found the problem, upon closer inspection of the needles (which are B1FH) I've found some wear on one side of both of them. The photo probably doesn't show much but the upward facing side has wear on it to flatten the round off slightly.



It seems to be a significant amount of wear, I'm assuming from either lots of use or some misalignment of jets and needles.

So, the new questions is whether to replace just the needles, or both the needles and jets and also does anyone know a good set of needles and jets for the 4.4l motor?

There may be more info on a 4.6 with carbs and probably the UK would be where to look .

I haven`t looked for a while but there used to be places in the UK that reconditioned them and they may have what you want .

Although unless you intend to tow heavy stuff alot or run full throttle most of the time the std ones may work well enough , the reason i say this is because our 4.0ltr has held full throttle for 2 , 3 minutes or better towing a tandem with a RR on it up hills in mid summer and running lean hasn`t been a problem with it .

Though yours is a bigger capacity .

The B1FH needle belong to carbs that came from what is know as a high compression engine 9.35:1 , if the butterflies have poppet valves fitted it could be telling they are around 1985 and the last of this type we got here .

Excellent, I'll have a look around thanks.

This car is mainly a camping truck with the occasional bit of off roading so not chasing super power or anything. I'll have a look around but might end up with the same needles and see how they go. I can always run it slightly richer if need be but the 4.4 runs at much lower revs than the 3.5 so might be alright.

Yes, the butterflies have the poppet valves in them (I assume to help with a smooth idle?) so it does look like these are off a late model. For memory I was told the 4.4 and these carbies were fitted into an 85 RRC so that all fits as well.

My only other concern is all the various vacuum ports on the carbs, I assume they were originally for the anti pollution gear such as charcoal canister etc. so have just blocked them all off. The only open airways are for the main intakes, dizzy advance and rocker cover vents. In addition to the manifold vacuum ports for the centre diff and the brake booster.

Unless some of these ports are for carb balancing perhaps?

Not that i know of just the ones that go over the main orifices .

The adapters between carb and the aircleaner pipe is where the canister pipes go .

The poppets are an emission thing , they let some air/fuel through on over run which is supposed to produce less hydrocarbon or what ever it is .

The early ones didn`t have them , just a flat disc they are interchangeable .

Some have removed them and soldered the cover of the valve back on because it would slightly improve airflow .