840851 Mercruiser STUD

Table 1
Required Tools
Part Number Part Name Quantity
1U-5470
or
198-4240 Engine Pressure Group
or
Digital Pressure Indicator 1
Illustration 1 g00293196
1U-5470 Engine Pressure Group
Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group" for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, "Using the 198-4240 Digital Pressure Indicator" for the instructions that are needed to use the 198-4240 Digital Pressure Indicator.
Check the Air Filter Change Indicator Gp on the air inlet for a reading of the restriction.
Inspect the engine air cleaner inlet and ducting in order to ensure that the passageway is not blocked or collapsed.
Check for dirt tracks on the clean side of the engine air cleaner element, the air inlet hose, and the clamps. If dirt tracks are observed, contaminants are flowing past the engine air cleaner element, the seal for the air cleaner, and/or the air inlet hose.
Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element.
Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.
Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts.When working on an engine that is running, avoid contact with hot parts and rotating parts.
Use the differential pressure gauge of the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator.
Illustration 2 g01176673
Air inlet system (typical example)
(1) Turbocharger
(2) Air Inlet Piping
(3) Test location
(4) Air cleaner
Connect the vacuum port of the differential pressure gauge to test location (3). Test location (3) can be located anywhere along air inlet piping (2) after engine air cleaner (4) but before turbocharger (1). The air flow through a new engine air cleaner element must not have a system restriction of more than the following amount: Maximum restriction ... 3.7 kPa (15 inch of H2O)The air flow through a used engine air cleaner may have an additional restriction. The air flow through a plugged engine air cleaner will be restricted to some magnitude. In either case, the restriction must not be more than the following amount: Maximum restriction ... 6.2 kPa (25 inch of H2O)Exhaust Restriction
The muffler, catalytic converter/muffler, and diesel particulate filter will become extremely hot during engine operation. A hot muffler, catalytic converter/muffler and diesel particulate filter can cause serious burns. Allow adequate cooling time before working on or near the muffler, catalytic converter/muffler and diesel particulate filter.
Excessive idling can cause the muffler, the catalytic converter/muffler, or the Diesel Particulate Filter (DPF) to plug. A plugged muffler, a plugged catalytic converter/muffler, or a plugged DPF will lead to an increase in exhaust back pressure. Operating the engine in cold conditions may cause the muffler, the catalytic converter/muffler, or the DPF to plug. One indication of a plugged muffler, catalytic converter, or DPF is poor engine response.Exhaust Back Pressure for Diesel Particulate Filter (DPF)
An absolute pressure sensor is located on the inlet of the DPF. This sensor will display the exhaust back pressure.