s/v TWIG

Saga 43 - Hull #39


Daily routine, before starting your engine

  1. Check engine lube oil level and coolant level.
  2. Check alternator/water pump belt condition and tension.
  3. Make a quick visual check of engine and sump for any coolant, fuel or oil.
  4. Visually check seawater strainer for debris. (Is the seacock open?)
  5. Visually check fuel filter bowl for signs of water or algae growth. Black specks indicate algae growth, water will show as a clear bubble at the ) bottom.
  6. Check for trailing lines, sheets, or dinghy painters (tow line) that could foul the prop.

IMPORTANT CAUTION #1: As the exhaust system relies entirely on the pressure of combustion gas to discharge the cooling water from the muffler through the transom pipe, there is a potential to flood the exhaust system and possibly even the engine cylinders with seawater if the engine starter motor is cranked for more than one minute total time, without the engine actually starting. If the engine fails to start within 30 seconds total and accumulative cranking time— DO NOT CRANK ENGINE ANY FURTHER with sea water intake valve open. SERIOUS DAMAGE TO THE ENGINE MAY RESULT! You may crank the engine with the inlet seacock closed to diagnose the starting problem. Be prepared to quickly open the seacock after the engine starts.

IMPORTANT CAUTION #2: If whenever the engine is being operated and the overheat alarm sounds, or there is no raw cooling water exiting the exhaust pipe at the stern, immediately shut down the engine and investigate. Engine damage will result if ignored.

Furthermore, since the exhaust system is largely water-cooled and non-metallic the excessive heat of un-cooled exhaust gas will melt the muffler and exhaust hoses, resulting in a situation where following seas could potentially enter and flood the yacht through the exhaust pipe.

Always inspect the integrity of the exhaust system after any engine overheat incident, no matter how minor. If you are in a situation where you must have the engine propelling the boat, such as a narrow channel or heavily trafficed area, the safety of your crew and boat must be considered more important than damage to the engine. Every captain must be able to make the correct decision by themselves, neither this manual nor any other advice is capable of covering every contingency.

Starting and Operating the Engine

Please refer to the engine Owner’s Manual for starting procedure and engine panel functions. Thoroughly familiarise yourself with engine shift and throttle controls before attempting to start the engine or get underway.

  1. Turn the engine start battery switch to “ON.”
  2. Check that engine water intake valve is open.
  3. Check that the gear shift lever is in neutral.
  4. Follow specific instructions as laid out in engine Owner’s Manual.
  5. After starting engine, immediately check exhaust pipe in stern for cooling water flow. Shut down engine and determine cause, if cooling water does not flow within 10 seconds of engine starting.

Note: When a folding propeller is fitted, excessive vibration may occur when the engine is placed in forward gear. This is usually caused by one blade of the propeller not opening. Should this occur, slow the engine to idle, shift into reverse gear and accelerate the engine. Idle the engine and shift to forward gear. This should open the offending blade.

Note: When sailing, it is always advisable to start the engine before the sails are lowered. In this way, it is still possible to manoeuvre if the engine should not start. However pay particular attention to sheets and other lines which may be trailing in the water before operating engine and possibly fouling the propeller. DO NOT OPERATE THE ENGINE WITH SWIMMERS IN THE WATER OR NEARBY! SERIOUS INJURY CAN RESULT.

Engine Shut Down

  1. Close the throttle to slow idle.
  2. Place the gear shift in neutral.
  3. Stop the engine by depressing red stop button on Yanmar panel on SB side of cockpit coaming.
  4. Turn engine panel key to OFF.
  5. Continue running engine blower for 5 min. (or longer) after engine shutdown to cool down engine compartment and eliminate fumes.
  6. If the engine is not to be used again for an extended period, the water intake valve should be closed. Place start key around valve.
  7. Turn the engine battery switch to OFF.

Engine Details

All necessary specifications and information concerning the Yanmar engine installed aboard your yacht may be found in the Yanmar Engine Owner’s Manual. Read this manual carefully so that it is thoroughly understood. The life and performance of the engine will depend upon the care it is given.

Remote Yanmar oil and fuel filters mounted forward for easy access (‘14). Engine hoses replaced (’13). Engine room work lights. Heavily insulated engine compartment. Steps and engine room front panel are hinged for easy access.

  • Brand: Yanmar - 800.622-5364 or 847.541-1900
  • Model: 4JH3E
  • Year Built: 2001
  • Continuous rating: 3650 RPM - 37 kW (50hp)
  • Maximum output power: 3800 RPM - 41KW (56hp)
  • Engine Type: Inboard
  • Engine/Fuel Type: Diesel
  • Serial number E23297
  • Weight 462 lbs
  • Marine Diesel Direct
  • Hours in 2006: 1330, 2016: 4048, 2017: 4493, 2018: 4572, 2019: 5000.

RPM & Consumption

The RPM sensor creates an AC signal based on the number of teeth. Currently configured for 117 teeth/232 pulses per revolution.

Type RPM GPH Knots Range Hr prop kw/hp max kw/hp
Low Idle 850 0.35 1.0
Mid Idle 1000 0.40 2.3
High Idle 1200 0.46 3.0
1.4k 1400 0.47 3.7
1.5k 1500 0.48 4.0
Long-Range Min Cruise 1800 0.49 5.0
Long-Range Slow Cruise 1850 0.60 5.3 04.5/06 22.0/29.5
Long-Range Cruise 1950 0.70 5.6 05.0/07 23.0/30.8
Cruise Low 2200 0.89 6.2 07.5/10 26.5/35.5
Cruise 2300 0.90 6.3 07.5/10 26.5/35.5
Cruise 2400 1.00 6.4
Cruise Mid 2500 1.10 6.7 11.1/15 30.0/40.2
Cruise Mid 2600 1.25 7 16.4/22 32.0/42.9
Fast Cruise 2800 1.3 7.4 16.4/22 32.0/42.9
Max Cruise 3000 1.6 7.9 19.0/25.5 34.0/45.6
Hull Speed 3300 2.5 8.4 26.0/35 37.3/50.0
Typical Max w/ Alternator 3500 2.6 8.6 32.0/43
Continuous (Full Load) Max 3650 2.75 37/50 37.3/50.0
1 Hr Rated Max 3800 41/56 55
No Load Max 3925

Engine NMEA 2000 Gateway

The following information is available on the NMEA 2000 network.

  • Engine RPM
  • Engine Temp
  • Oil Pressure
  • 24v Alternator RPM - Sending to network roughly half actual RPM on “Starboard Engine”.
  • 24v Alternator Field Voltage (need 5k ohms resistor, 10mfd cap)
  • Ground for alternator RPM
  • Power In from 12v ignition circuit
  • 12v Alternator field voltage (need filter)


  • Change every 150 hours
  • SAE 15W-40 or SAE 30 or 40. Use CD or CG-4 grade or higher.
  • 5.6 quarts
  • Reverso OP-4 electric oil change pump. - 945.522-0882

Oil Filter Options

  • Yanmar 129150-35151, 129150-35151, or 129150-35170
  • Wix 51334
  • Napa 1334
  • Baldwin B1421

Raw Water Impeller

Replaced every 500 hours.

  • Yanmar 129670-42531
  • Jabsco 1210-003
  • Johnson 1027
  • Onan 132-162
  • Volvo 875811
  • BRC 00075


Two high output alternators are fitted on the engine. The 28v 185 Amp alternator begins charging the house bank above 800 RPM. Currently set for 27.9v.

  • 28v 185 amp (5kw) American Power HPI Alternator
  • 10 groove belt


The reduction gears and reverse gears are contained in the transmission casing attached to the after end of the engine. These gears normally require little maintenance. The gearbox oil should be checked from time to time; see the Engine Owners Manual for the location of the dip stick. To avoid damage to the gears and to increase clutch life, the engine should ALWAYS be at idle speed (<1000 RPM) when shifting gears.

Rebuilt @ 1330 hours in July, 2006 by Mack Boring 508.946-9200

  • Brand: Kanzaki
  • Model: KM 3A1, serial number 02493
  • Rebuilt at 1330 hours,
  • Gear ratio: 2.64
  • 0.65 liters, 0.75 quarts / 0.3 quarts.
  • 2.64/3.04 - prop 1441 RPM


A folding propeller is fitted, it must be recognized that it generally has lower reverse thrust than other types. Plan your docking maneuvers accordingly.

When sailing, it is preferable to lock the propeller shaft to help engage feathering of the propeller by putting the engine in reverse gear after it has been shut off. This will prevent the propeller from rotating or “free-wheeling.” You should not be sailing at a speed of more than two or three knots when you shift into reverse. Sudden reversing of the direction of rotation of the prop shaft puts strain on the transmission, slower is better. The design of the Yanmar transmission is such as to prevent the transmission being shifted back into neutral until the transmission has stopped its rotation.

  • Forward Clockwise, viewed from stern. Walks to starboard.
  • Reverse Counterclockwise, viewed from stern. Walks to port.
  • Max 3-blade 19” Folding propeller (2020)
  • Zinc 70mm.
  • Drive Type: Direct Drive
  • Line Cutter:  Spurs Marine Model B for zincs.  http://www.spursmarine.com   800.824-5372

Prop Pitch

Pitch is easily adjustable by replacing a single bolt. It can be performed when in the water. Prop is usually slightly over-pitched to maintain higher load on engine during average cruising speeds. It enables more effective motor-sailing. The disadvantage is lower Max RPM and thus lower max power output.

The MAX PROP® EASY allows an angle variation of 2 degree increments in fwd and 4 degree increments in reverse, this corresponds to a variation in the engine RPM of about 13% at the same boat speed. Pitch and rotation of the MAX PROP® EASY can be changed as follows:

On the body of the propeller are two threaded bores, marked with letters “R” and “L”. Replace the “R” bolt for fwd and “L” for reverse. Both the set screw and bolt can be removed by the stainless T-handle tool.

For example inserting the #20 bolt in the forward rotation and 2 in the reverse rotation will provide a 20 degree angle for both front position and reverse rotation. Varying 1 millimeter the length of the bolts, blades inclination has a 2 degrees variation

Degrees Fwd Bore Rev Bore RPM @ 6kts Max RPM In Use
16 16 1
18 18 2400 3800
19 20 backed out 1 2 backed out 1 notch 2300
20 20 2 2200 3600
22 22 2000 3400 *
24 24 3 1800

Spare Prop

  • 3-blade bronze Max 3-blade 19” Folding propeller
  • Prop Pitch Setting: 18deg(11.5”) RH - X=E / Y=H (previously 20deg(13”) RH - X=K / Y=E)
  • Zinc 70mm.

Propeller Shaft

The propeller shaft is supported at the inboard end by the shaft coupling and at the outboard end by the strut which contains a water lubricated bearing (cutless).

  • Stainless steel 1 ¼” prop shaft with bronze strut
  • Shaft - length: 40 inches, diameter: 1.25 inches
  • Morse or Johnson Duramax Cutlass Sleeve Bearing 1.25 ID / 2 OD / 5 L
  • Bronze 2 piece Shaft Strut with 5 inch width by Buck Algonquin
  • Solid Transmission Shaft Coupler 50MCY00412. YX 4” flange. 10MM Bolts (MCY004) by Buck Algonquin

Shaft Alignment

The shaft is coarsely aligned at the factory and the boat should not be operated (except briefly and with low engine speed) until a final alignment has been carried out. The propeller shaft and the engine can only be properly aligned after launching. This should be done by your dealer prior to delivery to you. The alignment should be rechecked, at any time if there is excess vibration when the engine is running or if loss of engine speed becomes evident but particularly after a haulout. Improper alignment can cause premature wear of the drive line components. We recommend that a competent professional perform shaft alignment as misalignment can result in expensive repairs.

It is a good idea to do the final shaft alignment AFTER the rig is tuned and with the backstay tension fully relaxed. Backstay tension may affect alignment.

Briefly, alignment is checked in the following manner: a) Remove the flange bolts on the shaft coupling adjacent to the transmission case. b) Support the weight of the shaft and coupling, then slide the coupling faces together by hand. c) While holding the coupling faces together, insert a feeler gauge and check the clearance at four points around the coupling. (3,6,9, & 12 o’clock). There should be no more than .003” variation in the gap between the faces. If the coupling faces are misaligned, the engine mounts can be adjusted until the coupling faces match evenly. Replace and carefully secure flange bolts and locking devices after successfully completing the alignment check. Loc-Tite® nut seal is recommended on coupling and engine mounting nuts as they are subject to severe vibration.

Shaft Seal

The shaft passes through the hull at the stuffing box which is equipped with a “drip-less” type shaft seal.

The shaft seal is located at the inboard end of the fiberglass tube which passes through the hull. The fiberglass tube and the shaft seal are connected by means of a short length of flexible silicone rubber tubing held in place by hose clamps. These clamps and the stuffing box should be inspected on a regular basis. Replace clamps if any sign of corrosion or rusting is present. If leaking is found, the hose clamps should be checked. NOTE: The rubber tubing and clamps at the stuffing box must be inspected at least yearly.

Exhaust System

The exhaust system utilises a waterlift type muffler. In operation, the engine water pump draws water through the sea water intake valve, circulates it through the engine heat exchanger and then injects it into the exhaust elbow. The cooling water mixes with the exhaust gases in the muffler and is discharged overboard by exhaust gas pressures through the exhaust pipe in the stern of the yacht. From the engine exhaust elbow onward the system is water-cooled and constructed of non-metallic, non-corrosive components and should provide you with years of dependable service. However at least semi-annually, inspect the system for leaks and replace any hose clamps that show signs of corrosion.

Fuel System

  • Fuel vent air/fuel seperator - Racor Lifeguard LG100; www.parkercom  800.344-3286 Installed starboard side aft. It’s blue. Both tank vents combined under galley sink against hull.
  • Electric fuel pump (‘15) with constant or momentary switch.

Fuel Tanks

2 aluminum tanks (314 liters / 83 gallons) and 2 portable plastic (40 liters / 10 gallons) for 354 liters (93 gallons) total.

Two aluminum fuel tanks are located beneath the cabin sole and are static grounded. The fuel tank selector in the engine compartment has dedicated valves for switch over of both feed and return lines. The manifold is located in the engine compartment. Be sure to switch both unless intentionally moving fuel from one tank to the other.

Forward Diesel Tank

  • 170 liters (45 gallons)
  • Starboard deck fill
  • Replaced in 2015

240-33 Ohm Calibration Table

Sensor Ohms Liters Percent
224.9 0-29 0
189.8 30-41 17.78
160.8 42-56 24.45
137.7 57-46 33.34
119.2 65 37.78
104.2 76 44.45
30.6-35 170 100


Alarm On Liters Off Liters Percent
Very Low 10 56 1
Low 40 56 17
Nominal >58 25

Aft Diesel Tank

  • 143 liters (38 gallons)
  • Port deck fill

240-33 Ohm Calibration Table

Sensor Ohms Liters Percent
226.8 0-19 0
180 20-25 13.91
133.2 26-35 18.08
124.7 36.5-46 25.03
117.2 47 31
117.2 79 31
29.2-33.5 ?-144 100


Alarm On Liters Off Liters Percent
Very Low 10 36 1
Low 25 36 17
Nominal >37 25

Plastic Portable

  • Yellow 20 liter (5 gallon)


Even though your SAGA is equipped with a diesel engine, before opening the fuel inlet deck cap, it is prudent to ensure that all open flames aboard the yacht are extinguished, no person is smoking and that the electrical main switch as well as all electrical circuits are turned to “OFF.” It is good practice to close all ports and hatches adjacent to the fuel fill to keep the diesel fumes out of the cabin. Locate the tank vents and monitor them throughout the fueling operation.

Be careful not to fill tanks at a rate faster than the vents can relieve air pressure in the tank. Fuel docks that seldom have sailboat clients often have higher pressure fuel fills that may cause problems of fuel backing up in the fill pipe. Slow down the fuel flow, or stop fueling if there is any spitting of fuel from the vent or fill pipe. With the tanks located deep in the bilge there is considerable hose length and filling is slow, this is normal. Once the tank has been filled, close the inlet cap tightly and wash down any spills with fresh water and an approved biodegradable oil dispersant.

Fuel Quality

For specific fuel grades refer to the engine Owner’s Manual. Clean fuel is critical to diesel engine performance and service life. As diesel fuel is stored (in your yacht’s tanks or ashore before you purchase it) water buildup from atmospheric condensation and the growth of micro-organisms are constantly degrading the fuel. Use of secondary fuel filters (such as the Racors) and approved fuel conditioners and biocides (such as RACOR® brand or BIO-BORTM) are recommended. Try to purchase your fuel at high volume locations. In remote cruising locations, or whenever fuel quality is suspect, use of an external flow-through “pre-filter/water separator” (Baja filter) is highly recommended when filling up.

Fuel Filters

  • Primary Filter - Dual, switchable Racor R20P spin on. Change @ 150 hours - RACOR 220/R24 series (R20P) 10 micron.
  • Racor vacuum gauge
  • Algae-X fuel conditioner system
  • Secondary Filter - Change @ 300 hours - Yanmar #129470-55701 or #129470-55702 (NAPA #3390)

Equipped with a set of RACOR® fuel filter/water separators in addition to the paper element filter supplied by the Yanmar. Consult the RACOR® instructions and the engine owner’s manual for instructions on how and when to service the filters. Be sure to obtain replacement filter elements for the model of filters installed on your SAGA and carry them with you at all times. Filter element life is controlled primarily by the quality of fuel and secondarily by the amount of fuel used. The quality of fuel is often unpredictable. The fuel filter bowl should be checked every day and the paper element after every 50 hours of service. The filter element should be replaced whenever there is visible contamination of the filter surfaces. The filter element should be replaced prior to the start of every sailing season even if they appear to be clean.