Shrimp

I bought the car and it came with a Mikuni PHH 44mm carb.

I recently tore it down, cleaned it, and replaced the seals that weren't bad in the first place but tore when I broke it down to clean it.

There was oil in one of the barrels that had settled behind the large venturi so I dunno what happened.

Everything is spick and span on the inside now, and it was just recently installed on the car.

I don't really have it tuned yet, I don't know much about it but I read that putting the pilot screws all the way in the 1-1.5 turns out was the norm.

http://www.youtube.com/watch?v=0FErmvpk_Oo

It doesn't do so well at low rpms and like to bog down but at higher rpms it sings.

Anyone mind directing me to some knowledge on tuning this thing and what all needs to be connected to it.

Right now I just have two fuel lines going to the fuel pipe assembly, a line that was hooked to the original intake manifold (there was an input on the new manifold so I got a new hose and put it on), and a non-existant throttle cable (at the moment).

There are two inputs going to the accelerator pump, do I need something going to those?

There is also another brass input for a small ID hose (maybe 1/8" or so) on top of the carb and it's about an inch long and has a bend in it that I have nothing going to.

Need direction, willing to read kthx.

Shrimp

So I did some more research...

At Mazspeed.com they have some info on the Mikuni 44m 2-barrlels:

Solex Mikuni 44 PHH side draft 2 barrel: These carbs are no longer available, but there are still some used ones that come up for sale occasionally. The performance will be comparable to the Weber 45 DCOE side draft 2 barrel. I ran one for several years on first a stock ported 12A, then on a street ported 12A. Weber 45 DCOE side draft 2 barrel: These carbs are a good compromise between power and smoothness or driveability on the street. Gas mileage may be slightly less than using the modified Nikki 4 barrel. As with all big 2 barrel carbs, you cannot open the throttle quickly at low engine speeds. The minimum engine speed at which a big 2 barrel will not bog varies depending on the size of the venturies, but it usually you cannot floor them below 3500 rpm without the engine stumbling. This is usually a rude shock to someone new to a 2 barrel, but that is just the laws of physics. You can overcome the bog by learning how quickly you can open the throttle and when you can give it full throttle. These carbs require a special intake manifold made just for this carb and your engine. I strongly recommend that you buy a complete kit with carb, air filter, intake manifold, and the linkage required. If you buy a carb off of some other application, it will take you time and money to get all the other necessary pieces rounded up, and a lot of time to get it all running smooth.



So basically, the bogging down at low rpms is normal and is gonna happen with a larger 2 barrel carb. So I think I am pretty close to having it running right as it is now since once I get to above 3500-4000 RPMs I can go WOT and the 12a just sings like crazy. I know I have to put it under load to really tell how it will act but I have to get a throttle cable before I can do that.

Shrimp

So the two inputs near the accelerator pump are to the cooling body assembly which is supposed to be hooked to the return line to pass fuel through it to cool the carb. Everything I read says people don't use it and instead cap it off.

I also have to other inputs near there that are positioned closer to the butterflys. They are labeled as plugs on the exploded parts diagram but have inputs like you would put a hose on them.

Shrimp

I got it roughly dialed in as best I could without synching the two barrells and without having a vaccum guage. I don't have the tools so until I can get some or find someone with them it will have to do.

I got it starting from a cold engine without having to use starting fluid anymore so that is a plus. The starter on the carb works well at getting it started when it's cold. Once it's warm it runs pretty damn good and it screams at higher rpms.

Do springs on carbs wear out over time? I have my throttle cable attached and the weight of the pedal is holding the butterflys open. Maybe I need some new springs or heavier springs?

fc3sls1

Most Carbert cars require the addition of two external return springs.

Shrimp

I got a chance to do a road test through first and second and above 3500 it pulled really well.

You REALLY gotta be gentle with the pedal below 3500 or you WILL bog the engine and kill it, but after that WOT is no problemo.

I think I do need some extra return springs and I may even need to replace the spring on the gas pedal. I still think a bit longer throttle cable is necessary though.