Please consult your dealer for this information that way you know it is correct
Here is what I could find
SUZUKI MARINE ENGINES Spark PlugsEngine......Model......Year......Standard Plug.........Premium Plug 2-cyl..........DT40......82-80.....NGK4322 (BR8HS)...NGK7001 (Iridium BR8HIX)
2-cyl..........DT40c.....92-84....NGK5510 (B8HS)......NGK7001 (Iridium BR8HIX)
2-cyl..........PU40......93..........NGK4322 (BR8HS).....NGK7001 (Iridium BR8HIX)
3-cyl..........DT65......92-85.....NGK5510 (B8HS).......NGK7001 (Iridium BR8HIX)
3-cyl..........DT75......96-93.....NGK4322 (BR8HS).....NGK7001 (Iridium BR8HIX)
3-cyl..........DT85......93..........NGK4322 (BR8HS).....NGK7001 (Iridium BR8HIX)
3-cyl..........PU55......93-89.....NGK5510 (B8HS).......NGK7001 (Iridium BR8HIX)
3-cyl..........PU85......93-89.....NGK5510 (B8HS).......NGK7001 (Iridium BR8HIX)
4-cyl..........DT115....00-98.....NGK4322 (BR8HS).....NGK7001 (Iridium BR8HIX)
4-cyl..........DT115....90-81.....NGK5510 (B8HS).......NGK7001 (Iridium BR8HIX)
4-cyl.
4-Stroke....DF115....04-01.....N/A..........................NGK6418 (Iridium BKR6EIX)
4-cyl.
4-Stroke....DF115....04-01....NGK7092 (BKR6EGP)..N/A
4-cyl.
4-Stroke....DF60......04-98....NGK4008....................NGK6637 (Iridium BPR6EIX)
4-cyl.
4-Stroke....DF60......04-98....NGK7084....................N/A
4-cyl.
4-Stroke....DF70......04-98....NGK4008...................NGK6637 (Iridium BPR6EIX)
4-cyl.
4-Stroke....DF70......04-98....NGK7084...................N/A
ALL............DF4........04-03....NGK4008...................NGK6637 (Iridium BPR6EIX)
ALL............DF4........04-03....NGK7084...................N/A
ALL............DF6........04-03....NGK4008...................NGK6637 (Iridium BPR6EIX)
ALL............DF6........04-03....NGK7084...................N/A
ALL............DT4........87-85....NGK7331 (BP6HS).....NGK3419 (Iridium BR6HIX)
V6.............DF225.....04.........N/A............................NGK6418 (Iridium BKR6EIX)
V6.............DF225.....04.........NGK7092 (BKR6EGP)..N/A
Hope This Helps.