Presentation - Volvo Penta 230 Workshop Manual

230, AQ131
251DOHC, AQ171
The engines are 4 cylinder gasoline engines. All the
engines are equipped with freshwater cooling in
combination with seawater cooling. The seawater
system is powered by a direct drive impeller pump.
The thermostat controlled freshwater system is pow-
ered by a circulation pump.
The engines are manufactured with two different
product designations. During 1989 Volvo Penta be-
gan designating engines based on their cylinder dis-
placement according to the ISO norm 8665. The
older product designations of AQ131, AQ151 and
AQ171 (where the number provided an approximate
indication of output) were withdrawn. The new des-
ignation 230 replaced AQ131, 250 replaced
AQ151and 251DOHC replaced AQ171.
250, AQ151 and 251DOHC, AQ171 are equipped
with an oil cooler. 230, AQ131 has a single
carburettor and the others have twin carburettors.
The exhaust system has seawater cooled exhaust
pipes. 230, AQ131 and 250, AQ151 models have an
overhead camshaft while 251DOHC, AQ171 has
double overhead camshafts with hydraulic valve lift-
ers. 251DOHC, AQ171 is a 16 valve engine. 230,
AQ131 and 250, AQ151 models have conventional
marine ignition systems while 251DOHC, AQ171
has electronic ignition.
8

Presentation

Product plate
The product plate is located on the cylinder block
beside the starter motor. The product plate provides
the following information;
(1) Product designation, i.e. AQ131D
(2) Product number, i.e 867902
(3) Serial number (10 digit)
(4) Basic engine, serial number
250, AQ151