Mikuni PHH

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Revision as of 03:31, 25 August 2011

Mikuni PHH 40 and PHH 44 sidedraft carburetors are a licensed version of the famous Solex sidedraft carburetor. They may be marked Mikuni, Solex or both. They use the same base flange pattern as Weber DCOE and Dellorto DHLA carburetors. Mikuni was the brand Nissan Competition sold for A-series engines. Mikuni made the PHH series from around 1970 until 1995. A PHH 50 was also made but are too big for regular A-series engines. Mikuni "Solex" is far more popular than Webers in Japan.

Overview

• Mikuni recommended fuel pressure is 2.84 - 4.98 psi

• Mikuni calls the idle-mixture screw the "Pilot" screw.

• Carb flange same as DCOE. The air cleaner side bolts are spaced slightly different. Elongating DCOE air cleaner holes lets them fit on the PHH.

• Choke: A most interesting feature of the PHH is that instead of a choke butterfly valve for cold-start enrichment, it using an enriching circuit called a "starter" which rotates to open the starter jet.

• Starter: Yellow circles. Connect choke cable to these.
• Pilot Screws: yellow arrows
• Idle speed screws: Green arrows

• Mikuni PHH Carburetor Service Manual (PDF)

• Size is stamped on the throttle blade

  165 = 1.65 inch (40 mm)

Fuel Pump

Mikuni recommended fuel pressure is 2.84 - 4.98 psi. A stock A14 pump should work fine. They are rated 2.8-3.8 pounds (early A12 was lower pressure).

You can easily test the fuel pump with a vacuum/pressure gauge with engine idling. Then remove hose and see how many CCs come out in 60 seconds. A14 pump at 1000rpm should pump minimum of 1.3 liter.

That A14 rating of 1.3/minute is good for 125 HP engine. That's a pretty hot street motor, not many A14s can do that naturally aspirated. For a racing A14 you'll want a higher volume pump.

So test your pump. It may put out 1.5 liter/minute. Then no worries even on a very hot street A14.

Parts

Nissan Competition

Nissan Competition sold Mikuni kits for Datsuns, including this one for A-series engines:

40mm Mikuni

40MM MIKUNI/SOLEX INDUCTION SYSTEM

This induction system requires the use of the GX or competition cylinder head. With appropriate jetting and venturi sizing this system can be applied to any modified A-series engine.

6010-H2310 40MM CARB SET
 Main jet 120
 Air jet 180
 Pilot jet 50
 Venturi 33mm
99996-H1140 INTAKE MANIFOLD
99996-H1149 STUD & PLUG KIT Required when installing 99996-H1140
99996-H1150 MANIFOLD GASKET
14330-H2310 HEAT SHIELD (2)
16174-H2310 INSULATOR (4)
16174-M0820 INSULATOR (FWD) Inclined 10° (4)
16176-H2310 INSULATOR GASKET (8)
16360-H2310 LINKAGE ASSY
18200-25720 ACCELERATOR CABLE

44mm Mikuni

44MM MIKUNI/SOLEX INDUCTION SYSTEM

This induction system requires the use of the GX or competition cylinder head. With appropriate jetting and venturi sizing this system can be applied to any modified A-series engine.

16010-M0820 44MM CARB SET
 Main jet 160
 Air jet 180
 Pilot jet 55
 Venturi 37mm
99996-H1144 INTAKE MANIFOLD
14001-M0820 INTAKE MANIFOLD (FWD)
99996-H1149 STUD & PLUG KIT 
 Required when installing 99996-H1144
99996-H1150 MANIFOLD GASKET
14330-H2310 HEAT SHIELD (2)
16174-20100 INSULATOR (4)
16176-20100 INSULATOR GASKET (8)
16360-H5720 LINKAGE ASSY
18200-25720 ACCELERATOR CABLE