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Super BN

Troubleshooting Guide


Possible Causes


Hard Starting

Incorrect use of primer

Review primer operation

Fuel lines improperly connected

Reconnect in correct sequence

Intake air leak

Check manifold connections

Ignition problem

*Repair or replace as necessary

Low cylinder compression

*Repair or replace as necessary

Idle speed set too low

Adjust idle speed according to

speciications in owners manual

Clogged idle circuit

Remove carb and chemically clean

Improper adjustment of low speed


Adjust low speed adjuster for a

smooth idle

Slow return to idle

Idle speed set too high

Adjust idle speed according to

speciication in owners manual

Throttle linkage sticking

Clean and inspect linkage, lubricate,

repair or replace as necessary

Throttle cable sticking

Correct routing or replace as


Engine idles but won’t rev up

Pop-off pressure too high or low

speed jet too small

Adjust pop-off or low speed jet per manual

Engine “loads up” during extended

idling, i.e., in 5 mph zone

Leaking anti-siphon valve

Replace Valve

Leaking needle valve

Clean or replace needle valve

pop-off pressure to low

Increase pop-off pressure - See “Low Speed

Adjuster” section on Super BN tuning page

Low speed jet too large

Replace low speed jet with smaller size jet

Engine surges when cruising at con-

stant throttle setting

Incorrect air/fuel mixture

Mid range - change low speed jet

High speed - readjust high speed


Engine does not develop full power or

misses during acceleration

Clogged air cleaner/lame arrestor

Clean as necessary

Throttle not synchronized (Dual carb


Re-synchronize carbs

Clogged fuel ilter or water separator

*Clean as necessary

Components loose in carb, i.e., jets

Tighten as necessary

Ignition problem

*Repair or replace as necessary

Low cylinder compression

*Repair or replace as necessary

Carburetor is too lean at full throttle

and turning out high speed adjuster

has no effect

Needle valve size is too small for

engine needs

Replace jet with larger size

High speed jet too small

Replace jet with larger size

Carburetor too large for engine

Use more restrictive lame arrestor for

smaller carb

*Refer to Shop Manual for your craft