TROUBLESHOOTING
SERVICE MANUAL NUMBER 26
Instrumentation Malfunction
Cause
Special Information
Faulty wiring, loose or corroded terminals
Faulty key switch
Faulty gauge
Test, as outlined in SECTION 4D
Test, as outlined in SECTION 4D
Test, As outlined in SECTION 4D
Faulty sender
Engine Noise
Important Information
No definite rule or test will positively determine source of engine noise. Use the following
information only as a general guide to engine noise diagnosis.
1.
Use a timing light to determine if noise is timed with engine speed or one-half engine
speed. Noises timed with engine speed are related to crankshaft, rods, pistons, piston
pins and flywheel. Noises timed to one-half engine speed are valve train related.
2.
3.
The use of a stethoscope can aid in locating a noise source. Because noise will travel
to other metal parts not involved in the problem, caution must be exercised.
If you believe noise is confined to one particular cylinder, ground spark plug leads one
at a time. If noise lessens noticeably or disappears, it is isolated to that particular cylin-
der.
4.
5.
Try to isolate the noise to location in engine: front to back, top to bottom. This can help
determine what components are at fault.
Sometimes noises can be caused by moving parts coming in contact with other compo-
nents. Examples are: flywheel or coupler; exhaust flappers rattling against exhaust pipe;
crankshaft striking (pan, pan baffle, or dipstick tube); rocker arm striking valve cover;
and loose flywheel cover. In many cases if this is found to be the problem, a complete
engine teardown is not necessary.
6.
7.
When noise is isolated to a certain area and component, removal and inspection will be
required. Refer to proper sections of service manual for information required for service.
If noise cannot be distinguished between engine and drive unit, remove drive from boat.
Run a water supply directly to engine. Run engine without the drive to determine if noise
is still there.
Index
Page 1C-22
90-861329--1 MARCH 1999
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 181 CID |
| Model Year | 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(6 votes, average: 5 out of 5)
Marine readers have rated Mercury MerCruiser GM 4 Cylinder 181 cid 3.0L Marine Engines Service Manual Number 26 5.0 out of 5.0 based on 6 product reviews. Thanks for sharing this material. Helps a lot after suffering with bad mechanics. spend too much money and nothing very good
great manual, makes impossible jobs possible. without a manual you can not do the job, a must have.
Great resource. Excellent information provided.
Need help to install automate choke
Need help to instal automate choke