Introduction – Cub Cadet Yanmar 3TNV72 User Manual
Page 166

FUEL SYSTEM
TNV IDI Service Manual
7-5
Introduction
INTRODUCTION
Figure 7-1
This section of the Service Manual describes the 
procedures necessary to remove, install, and time 
the ML fuel injection pump and its associated 
system components. This fuel injection pump is 
representative of the fuel injection pumps used on 
other TNV IDI model engines.
Fuel Injection Pump
Note: If the ML fuel injection pump itself
requires servicing, it must be taken to an 
authorized Yanmar FIE (Fuel Injection 
Equipment) repair facility.
The following describes the features of the ML fuel 
injection pump, manufactured by Yanmar.
The fuel injection pump is a very important 
component of the engine. It is capable of making 
very precise fuel delivery adjustments according to 
the varied loads applied to the engine.
All of the fuel injection pump components are very 
precisely machined. It is extremely important to 
follow good service practices and maintain 
cleanliness when servicing the fuel injection pump.
The Yanmar ML Fuel Injection Pump is an in-line 
type pump which consists of a fuel supply plunger 
(Figure 7-1, (1)) for each cylinder, a camshaft 
(Figure 7-1, (2)), and a pump housing 
(Figure 7-1, (3)). A delivery valve (Figure 7-1, (4)) 
connects to a high-pressure fuel line for each 
cylinder. The fuel injection pump housing contains 
a governor (Figure 7-1, (5)).
Fuel from the fuel tank to the fuel injection pump is 
delivered by a low-pressure electric fuel pump. On 
a few special models, a mechanical fuel pump is 
used instead of an electric pump. The mechanical 
fuel pump is mounted to the fuel injection pump 
housing in place of the cover plate 
(Figure 7-1, (6)).
Fuel to be injected into the cylinders is pressurized 
by the up and down motion of each 
camshaft-driven plunger, and is then supplied by 
the high-pressure fuel lines to the respective fuel 
injector.
(4)
(1)
(3)
(5)
(6)
(2)
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TNV_IDI_ServiceManual_(3TNV72 for YN only).book 5 ページ 2007年11月29日 木曜日 午後2時58分
