Rebuilt Mercury 300 Promax Drop on powerhead

RossM

Senior member
Joined
Mar 4, 2006
Messages
1,692
Boat make
Phantom 23
Freshly rebuild 300 Promax


Exhaust chest ported
Liners removed to gas flow all the transfers
once removed, liners were ported (exhaust, transfer and inlets) before refitting and port matching to block
Front half cut and counter bored to increase crankcase compression
Rod slots opened up and gas flowed
All oversize pistons 2xBrand new ones in the bottom, the rest were replaced less than 20 hours ago when the motor was first built.
Cylinder heads cut to 57cc which will hapily run on Pump fuel
Weight matched Rods (end to end balanced too)
Lightweight flywheel


Injector have been cleaned and are all within 2 CC's
New spark plugs, cleaned regulator screens, all bleed pipes replaced,
Reed cages have been linished perfectly flat and fitted with CCM Reeds
Never had any holes or welds in the block
300 Promax ECUs with 7000 rpm limiter

This is an awesome powerhead which owes me a small fortune. Its not seen fuel since being built so will require running in. I have loads of pictures of the machining and build process if you'd like to see how much work went into it.

Asking £5,000 as a drop on powerhead ready to go
 

Attachments

  • 20220802_120521.jpg
    20220802_120521.jpg
    128.9 KB · Views: 103
  • 20220802_120728.jpg
    20220802_120728.jpg
    119.9 KB · Views: 116
  • 20220802_120958.jpg
    20220802_120958.jpg
    110.1 KB · Views: 107
  • 20220802_121138_001.jpg
    20220802_121138_001.jpg
    119.6 KB · Views: 95
  • 20220802_121144.jpg
    20220802_121144.jpg
    93 KB · Views: 68
  • 20220802_121331.jpg
    20220802_121331.jpg
    110 KB · Views: 64
  • 20220802_121434.jpg
    20220802_121434.jpg
    127.1 KB · Views: 253
  • IMG_20220724_123802.jpg
    IMG_20220724_123802.jpg
    102.2 KB · Views: 93
Internal works
 

Attachments

  • boostslot_zps9a5bd444.jpg
    boostslot_zps9a5bd444.jpg
    87.8 KB · Views: 62
  • Cleaned_zpsd184883b.jpg
    Cleaned_zpsd184883b.jpg
    125.7 KB · Views: 194
  • cyltop_zps83852a79.jpg
    cyltop_zps83852a79.jpg
    76.4 KB · Views: 92
  • 20130615_175924.jpg
    20130615_175924.jpg
    75.1 KB · Views: 65
  • 20130615_180602.jpg
    20130615_180602.jpg
    115.4 KB · Views: 99
Price drop to £4500
 
Back
Top