Hpdi Plugs 3 fouled

[metal128]

2001 HPDI 200hp

motor wont stay running

1,3,5 plugs fouled. Replaced 2 LP pumps that were leaking into the motor. Cleaned VST and checked med pressure (50 psi). Solid spark on all 6 cyls.

I can run the motor for 3 mins after the plugs are cleaned. After that it dies.

It seems like the exhaust is clogged on that bank of cyls. Ive worked on this thing for days. I am about to remove the powerhead and check for an exhaust blockage.. But before I do this any other suggestions?

Thanks for your help...

[boats.net]

Start with a compression test. Check that have correct spark plugs for that serial number motor.

[metal128]

Compression within 10% of all 6

[metal128]

Plug are correct also

[boats.net]

Make sure you have good fresh gas in it. Check oil pump linkage is adjusted properly.