Yamaha F50D Servise Manual - page 85

4-6

0

1

2

3

4

5

6

7

8

9

10

A

Symptom 1:

 Limited engine speed (below 2000 r/min).

Symptom 2

Cause 1

Cause 2

Chec

king step

Ref

er to 

page

Buzz

er comes on 

(R model)

Ov

erheat aler

t indica-

tor comes on

Cooling w

ater does not 

discharge from the 

cooling w

ater pilot hole

Clogged cooling w

ater inlet

—

Chec

k the cooling w

ater inlets

.

10-10

Clogged cooling w

ater passages

—

Chec

k the cooling w

ater passages

.

10-10

Cooling w

ater leakage

—

Chec

k the cooling w

ater hose routing.

6-3

Damaged w

ater pipe or incorrect installa-

tion

—

Chec

k the w

ater pipe and its installation.

9-18

W

ater pump malfunction

Damaged w

ater pump 

impeller

Chec

k the impeller

.

8-6  

(F50D)

8-46 

(FT50C)

Chec

k the 

W

oodr

uff k

e

y.

W

ater leakage from w

ater 

pump housing

Chec

k the w

ater pump housing.

Chec

k the inser

t car

tr

idge

.

Chec

k the outer plate car

tr

idge

.

Ther

mostat malfunction

—

Chec

k the ther

mostat.

10-20

Ther

mos

witch malfunction

—

Chec

k the ther

mos

witch input v

oltage and 

contin

uity

.

5-15

Buzz

er comes on 

(R model)

Oil pressure aler

t indi-

cator comes on

Engine oil quantity

—

Chec

k the oil le

v

el.

10-12

Engine oil pressure decrease

—

Chec

k the oil pressure

.

7-1

Clogged oil str

ainer 

Chec

k the oil str

ainer

.

9-20

Clogged oil passages

Chec

k the engine oil passages

.

2-11

Clogged oil filter 

Replace the oil filter

.

10-14

Oil pump malfunction

Chec

k the oil pump assemb

ly

. 

7-26

Oil pressure s

witch malfunction

—

Chec

k the oil pressure s

witch input v

oltage 

and contin

uity

.

5-16

Troubleshooting the outboard motor