TECHNICAL BULLETIN
Ref No.:Date:

YMTQTB11-017
October 18, 2011

To: Yanmar Marine Regional Head Quarters andAll Yanmar marine distributors

Subjects: Yanmar Sailboat engine control lever position during sailingunder sail with engine stopped

1. Introduction
Yanmar wishes to inform you about the instruction of the control lever position during sailing undersail with engine operation stopped. This instruction is subjected to mechanical type gearboxes andsail drives only.

2. Operation instruction
2-1 Mechanical Cone clutch :Applicable models:Sail Drive: Models SD 40, SD50 and SD50-4T
Marine gear: Models KM2P, KM35P, KM35A and KM4A

When mechanical cone clutch type gearbox or sail drive is equipped with the following propeller:a. Fixed propeller:
When sailing under sail with engine operation stopped put control lever into Neutral. The output
shaft keeps rotating.
Notice:When control lever is put in Reverse position, cone slippage will be introduced and void yourwarranty and there is possibility that the clutch doesn't disengage. This can be a problem forengine re-starting.
There are options to stop free rotation of propeller-shaft if customer doesn’t want occur noisefrom rotating propeller:
1) For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
2) For marine gear: install the Shaft - Lock device, Yanmar does not supply, on the propeller
shaft.
b. Folding propeller: (including GORI Over-drive propeller)
When sailing under sail with engine operation stopped put control lever into Reverse position,
this to operate the folding propeller to fold close blade and output-shaft stops from rotating.
After this operation put the control lever back into Neutral.
c.

Feathering propeller:
When sailing under sail with engine operation stopped put control lever into Reverse position,
this to operate the feathering propeller into feathering position and output-shaft stops fromrotating. After this operation put the control lever back into Neutral.

Page 1 of 2

GTB2010005

TECHNICAL BULLETIN
Ref No.:Date:

YMTQTB11-017
October 18, 2011

2-2 Other Mechanical clutch:
Applicable model:

Sail Drive: Model SD20, SD31 (Dog clutch type)
Marine gear: Model KBW10, KBW20, KBW21(Mechanical single or multi disc clutch)

When mechanical dog clutch or mechanical disc clutch is equipped with the following propeller:a. Fixed propeller:
When sailing under sail with motor stopped put control lever into Neutral. The output shaft
keeps rotating.
Notice:When control lever is put in Reverse position there is a possibility the clutch does not disengage.
This can be a problem for engine re-starting.
There are Options to stop free rotation on propeller shaft if customer doesn’t want occur noise byrotating:1) For sail drive: install folding propeller or Feathering propeller instead of fixed propeller.
2) For marine gear: install the Shaft-Lock device, Yanmar does not supply, on the propeller
shaft
b. Folding propeller:
When sailing under sail with engine stopped put control lever into reverse position, this enables
the folding propeller to fold close blade and output-shaft stops from rotating. After this operation
put the control lever back into neutral or remain reverse position as you like.
c.

Feathering propeller:
When sailing under sail with engine stopped put control lever into reverse position, this enables
the feathering propeller into feathering position and output-shaft stops from rotating. After thisoperation put the control lever back into neutral or remain reverse position as you like.

Notice:Do above mentioned operations with a boat speed <3knts when sailing under sail withengine operation stopped.

Shuji AndoManager, Overseas Group
Quality Assurance Department
Marine Operations Division
Yanmar Co.LtdPage 2 of 2GTB2010005