SERVICE MANUAL NUMBER 26
TROUBLESHOOTING
Engine Overheats
Mechanical
Cause
Special Information
Engine rpm below specifications at
wide-open-throttle (engine laboring)
Damaged or wrong propeller; growth on
boat bottom; false bottom full of water
Wrong ignition timing
Timing too far advanced or retarded
Sticking distributor advance weights
Spark plug wires crossed (wrong firing
order)
Refer to “Carburetor Malfunction” in this
section
Lean fuel mixture
Wrong heat range spark plugs
Exhaust restriction
Jumped or improperly installed timing
chain
Valve timing off
A blown head gasket(s) normally cannot
be detected by a compression check.
Normally the engine will run at normal
temperature at low rpm, but will overheat
at speeds above 3000 rpm.
Engines that are seawater cooled:
Using a clear plastic hose, look for air
bubbles between seawater pump and
engine. If there are no bubbles present,
install clear plastic hose between
thermostat housing and manifold(s). If air
bubbles are present at a higher rpm, it is a
good indication there is a blown head
gasket.
Blown head gasket(s)
Insufficient lubrication to moving parts of
engine
Defective oil pump, plugged oil passage,
low oil level
Index
90-861329--1
MARCH 1999
Page 1C-31
| 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