Installation manual

7-11
90-898305
Twin Pressure Gauge:
2.5 & 3.0 LITRE
Part number of the twin pressure gauge used on Optimax product has su
The new gauge has improved schrader valve connections (screw on type).
The clip on style connectors have been removed and screw on connectors
with quick disconnects have replaced them. The new gauge will also have
FUEL & AIR marked on the gauge manifold. The fuel side will include a check
valve at the connector, to retain fuel in the gauge when gauge is disconnected
from engine.
To up-grade the current gauges in use, there will be an adapter kit available.
Two kits are required for the twin pressure gauge.
• ADAPTER KIT P/N 91-803804A2
Low Pressure Electric Fuel Pump System Failure
2.5 LITRE
If the low pressure pump, or the electrical connection to the pump fail, the
engine will start and run well at lower RPM. As the engine RPMs are
increased (somewhere above 3000) the engine may stall out, or not reach full
RPM. Fuel and air pressure will be lower then normal. Another symptom, if the
pump outlet fitting (upper) is very warm (too hot to touch), the pump itself is
failing.
Incorrect Grommet (Air Handling Assembly)
2.5 LITRE
There are two different grommets used on the Air Handling Assembly (AHA).
The grommet used on the 135 HP has a (1 5/8 in.) opening, which restricts air
flow into the air plenum. The 150 HP grommet has no restriction at all, and
only functions as a grommet for correct fit of the flywheel cover. If a 150 HP
grommet is incorrectly installed on a 135 HP, it will result in poor engine
acceleration due to incorrect fuel calibration. Symptoms are normally a surge
and shake over 3000 RPM, if the operator pulls back on the throttle the engine
will smooth out. Note: To reach maximum RPM, the engine can be throttled
slowly through this range. The Digital Diagnostic Terminal (DDT) will not
indicate any type of failure or fault.
Hard Starting
2.5
We have received some reports of hard starting 135/150 HP Optimax/DFI
engines. To date we have found 3 reasons (Listed below) for this condition.
1) Incorrect battery (low amp rating, or deep cycle battery used as cranking
battery.
2) Incorrect engine set-up, throttle cable, or roller to cam setting.
3) ECM calibration. We have found that the early ECM calibration may be to
lean for some engines. Refer to S/B 98
Notes
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