Engine and Propeller Resources

Repair Manual – Kanzaki zf_gearbox


Yanmar Tech Bulletin – Gearbox Position when Sailing?

Diesel Water Vapor Trap – less than $5 – solution to bugs in diesel fuel.  Diesel fuel will NOT grow bugs (bacteria) if it has no water.  The water gets in there in three ways: 1. the fill cap is not watertight 2. there is water in the diesel, contaminated fuel 3. water vapor thru the vent.  This filter stops the water vapor from getting to the diesel thru the vent.  IT HAS NOTHING TO DO WITH HOW FULL OR EMPTY THE TANK IS – water will not condense on the walls of the tank if the vapor can’t get there in the first place.   The tube is filled with something like this: Indicating   silica gel, and then is dried out in the oven or frying pan when the color changes.

Causes of Prop Walk – many contradictions out there, ie. It’s caused by differential “digging in” between the top and bottom of the prop.  OR It’s caused by the angle of the prop shaft. This is the BEST explanation that i’ve found anywhere, it makes sense and it has easy to understand diagrams.  But the bottom line is that with our Hughes 38s that have the shaft drive and the engine in the bilge, we have little prop walk compared to most boats with shaft drive, because the angle of the shaft is close to horizontal, AND the prop is close to the center of the boat.  These two factors combined make for little prop walk.  Problem?  Many docking plans (for instance Here) make use of prop walk to move the stern of the boat against the wind.  Hmmmm

Run Your Diesel HARD

Yanmar-2qm15_Service Manual

Volvo Penta Marine Schematics

Universal Engine Info Link

Universal M25 Service Manual

Universal M25 Owners Manual

Universal Marine Engine Schematics

Perkins-M20-25-30-35 Operating Instructions

Perkins 100 Series Workshop Manual

Kanzaki Transmission Service Manual

Transmission Schematic

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Yanmar Manuals

Yanmar-2qm15_Service Manual

Service Manual

Operation Manual

Operation Manual

Shop and Service Manuals

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Yanmar 3GM30

Yanmar 3GM30 engine seems to come with the Kanzaki KM3P transmission in either 2.62:1 or 2.21:1 gear ratios.

Atomic 4

Tune-up parts for Atomic 4

Indego Electronic Ignition for Atomic 4

Atomic-4 Transmission Service Manual

Atomic 4 Repair and Maintenance

Atomic 4 FAQ

Atomic 4 Specs

Atomic 4 Basics

Atomic 4 Parts List

Atomic 4 Cleaning From Good Old Boat

Atomic 4 Common Parts Interchange

http://pearsonvanguard.homestead.com/files/atomic4.htm

http://www.tartan34library.com/Engines%20-%20Atomic%204/a4manual2_2.pdf

Screen Shot Atomic 4 Torque HP Curve

Screen Shot Atomic 4 HP Torque HP Curve Stevedore

Torque curves courtesy of Robert Hess

Questions:  Since the engine is in the bilge for the Yanmar and the Atomic 4, the combustion air for the engine is reportedly to be vented through the mast.  Does anybody know for sure?

The vent for the gasoline or diesel tank is reportedly to be through a stantion.   Does anybody know for sure?

Volvo Saildrive

Some have stated that this was an option at one time.  I have seen three MKIII’s with Volvo Saildrive.  One owner claims his (1980) was installed at the factory and that he has the original factory manual with a Volvo-Penta MD11C 2 cylinder diesel Saildrive.  Another source claims that the Volvo-Penta engine is an MD17C. Engine is freshwater cooled by way of a heat exchanger for onboard domestic hot water.

http://www.bluemoment.com/manuals/VolvoMD11C_D_17C_D.pdf

www.scribd.com/doc/96796919/Volvo-Penta-MD11C-User-Manual#scribd

MitanSaildrive

Screenshot_2014-11-12-10-45-19

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Saildrives      

Saildrive diagram

Saildrive Plan    I suspect that the saildrive wasn’t approved by S&S:  note the quality of the changes in the drawing and the Hughes name at the bottom.

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Volvo Penta Saildrive Beneath Companionway

Volvo Penta Marine Schematics

An excerpt of an email from Robert Hess:

Standard procedure is to replace raw water pumps every 5 years, exhaust risers every 7 years, and heat exchangers/gear coolers every 10 – 15 years. Most sailors don’t do that (in the marine trade sailors are considered extremely cheap) and instead spend a lot of time and money diagnosing and repairing (and complaining about) components which have a fixed design life.
Kubota engines are used as the base engine for Universal diesels, Vetus diesels, Beta diesels, Nanni diesels. (However), many of the parts used to marinize Kubotas are not available at Kubota tractor shops. (Many other marine diesels from many manufacturers are based on Mitsubishi engines… new Perkins and Volvo engines use Peugeot blocks.)
Kubota
Although not an original option, the Kubota engines are popular replacements for the Atomic 4, because of the reliability of the Kubota diesels, and the company’s policy of freely offering the replacement parts numbers so you can buy replacement parts at tractor dealers.  Nanni, Beta and Universal all marinize Kubota diesels.  Here are some fine examples:

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Universal 20hp in H38 SV Verdia

The owner of the engine above writes  “The 20hp. engine cruises along just fine at 5.5 kn. at 2500 rpm with modified Campbell sailer prop.  Averaging about 1/3 to 1/2 gall. per hr.  Top speed under power is 7 kn.  With 4 jerry cans I have about 500 mile range.”

Universal Engine Info Link

Universal M25 Service Manual

Universal M25 Owners Manual

Universal Marine Engine Schematics

Sailnet Thread about Universal Diesel Engine Interchange Parts

Sailnet Thread about Universal Fuel Injector Interchange

Propeller

ScreenShot of PropCalc Hughes 38Courtesy of Rob Hess

One owner has mated a 14×9 2-bladed fixed propeller to the A-4 motor with the 2:1 reduction gear.  He reports that the 15×10 3-bladed prop was too much prop for the A-4 engine.

Another owner has a Universal diesel (Kubota) 20hp with a 14×6 Campbell Sailor 3-bladed prop (the previous 15×8 was overpropped for this motor)

A Beta diesel dealer (a Kubota based engine) recommends the Beta 25 with a 2:1 transmission, stating that propped correctly it will consume 1 US gallon in 3 hours at cruising RPM.  He states that the Beta 30 will create too many installation issues.  His prop calculator gives optimum results of 14×9 or 13×10 3-bladed Michigan Wheel MP3 or DJ355.

One owner reports:            “There’s very little exposed shaft between the cutlass bearing and the prop. This only leaves room for one donut zinc anode, which may or may not last the year depending on local conditions, etc.”

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A Yachting Monthly discussion and testing of folding and feathering props.

PropTest in Pdf form    YachtingMonthly

An email from Robert Hess:

Jon

Some… don’t understand the difference in horsepower between a direct drive Atomic Four (no reduction gear, or a 1:1 V drive) and an Atomic Four with a 2:1 Paragon reduction gear (or 2:1 V drive).

Many sailboat owners also don’t understand that horsepower is a function of torque x rpm, so the propeller can limit horsepower if it doesn’t let the engine get up to its rated rpm (ie Atomic Four: 30 hp @ 3,500 rpm). They think that a bigger prop will let the engine turn slower at cruise speed, but what it actually does (besides lugging/damaging the engine) is lower the maximum rpm and therefore lower the maximum horsepower available from the engine.

A displacement hull sailboat cannot be driven past its calculated hull speed no matter how much horsepower is used. If it is towed past its calculated hull speed by a bigger boat it will start to zig-zag all over the place and either the tow ring or bollard will rip out of the deck, or the boat will suddenly dive under the water. That’s why whenever a sailboat is towed by a larger boat the owner should warn the tow boat captain not to exceed the smaller boat hull speed (ie around 8 kn for a Hughes 38), and should stand ready with an axe to cut the towline if the tow boat does suddenly start to go too fast (which often happens).

The maximum rpm the propeller on a displacement hull sailboat can turn before propeller cavitation becomes a problem is around 2,000 rpm.

If a direct drive (1:1) gear ratio Atomic Four engine (ie without a 2:1 reduction gear) is fitted it can only be revved up to 2,000 rpm. Over that the prop will cavitate badly. That means that the actual horsepower the engine is generating is limited to around 14 hp Screen Shot Atomic 4 HP Torque HP Curve Stevedore

which is all the power needed for smaller sailboats, so many smaller boats have a direct drive Atomic Four installed, with a prop that limits the rpm to around 1,600 to 2,000 rpm.

If an Atomic Four with a 2:1 reduction gear (or 2:1 V drive) is installed, as in the Hughes 38, then the full rated rpm (intermittent rating, which means it can be used for a maximum of 10 minutes to get out of the way of a big ship) 3,500 rpm of the engine can be used because the 2:1 gear ratio will drop the propeller rpm to a maximum of 1,750 rpm, and so the engine will be able to generate its rated full 30 hp without the prop cavitating.

Screen Shot Atomic 4 Torque HP Curve

Rob

VicProp Calculator

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The above table is from the VicProp Calculator and is for a Hughes 38 -a Yanmar 3GM30 with 2.21 reduction gear.

Another email from Rob Hess

Hi Jon
The prop diameter can be calculated according to engine power/rated rpm/gear ratio, but pitch is only a rough guess. The last part of an engine repower is a sea trial to check the propeller is pitched so the engine can reach full rated intermittent (not continuous) rpm at top speed, full throttle, normal weight & load, normal sea state. If the boat normally pulls a dinghy, then a dinghy should be pulled during the sea trial. Nobody can verify the exact correct pitch without a sea trial because boats get heavier as they age, and have different gear and tank and passenger loads. Many prop shops and engine dealers don’t understand how this works, and there is constant debate about it by people who don’t know what they’re talking about.
Rob

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Universal 30hp in H38 SV Water Lily

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Three Panel Engine Access

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Wet Exhaust

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SV Globi with Nanni (Kubota) 21 Hp – note the clean installation.  Raw water cooled.

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SV Dreamwalker 15 hp 2 Cylinder Yanmar(?)

 

Considerations for Repowering the Atomic 4

SV NorWester A4

Atomic 4 on SV Wiskejak (was NorWester)

Email from Robert Hess:

Jon

The standard Hughes 38 was available with a 30 hp (at 3,500 rpm) Universal Atomic Four gasoline engine fitted with a 2.04:1 Paragon reduction gear, or a Volvo Penta MD-17 diesel engine with a Volvo S-120 saildrive. I’m pretty sure the saildrive had a 2:1 reduction gear, because if the reduction gear was a 3:1 the large diameter prop required wouldn’t have fit (see below).

Many people don’t understand that repowering a sailboat involves calculating the optimum engine power, optimum gear ratio, and correct propeller diameter before ordering an engine, reverse gear, or propeller. Often the old propeller must be replaced, unless the new engine is very similar in power to the old one. The limiting factor on the Hughes 38 (and many other sailboats originally designed to be powered by a Universal Atomic Four… in larger boats usually an Atomic Four with a 2:1 reduction gear) is the distance between the centreline of the propeller shaft and the hull, directly over the propeller location on the shaft. This distance – doubled to give diameter, less 10% of propeller diameter for tip clearance, is the maximum propeller diameter that can be fitted, and the propeller pitch, gearbox ratio, engine rated maximum rpm must all be based on that. In most cases the larger the propeller diameter the better the thrust because a larger propeller can be turned slower, and the slower the propeller turns the less the slippage and wasted power. It is usually assumed that optimum pitch is slightly less to slightly greater than the diameter, ie 14″ diameter X 12″ to 16″ pitch will work OK. If the calculated pitch is outside that parameter then the propeller diameter, gearbox ratio, or engine rated rpm are not correct. So, the first thing to do when repowering is to measure the propeller “aperture” (as a diameter) and deduct enough from that get the maximum propeller diameter… leaving an extra space for 10% tip clearance. That number will be used by the engine supplier and the propeller supplier to calculate the correct horsepower, gear ratio, and propeller pitch for the new engine installation. In the case of the Hughes 38 another consideration is engine height so the engine will fit under the saloon floor without raising it (see below).

Once the repower is finished the boat should be sea-trialled to verify that the engine can reach rated rpm at full throttle/top speed (ie the rated rpm of a Universal M35-B is 3,000 rpm, so when the boat is run at top speed the tachometer must read 3,000 rpm. No matter which engine is used, many boats are over-propped and will not reach rated rpm… this causes engine lugging, which causes overheating and all sorts of mechanical problems… often the weak link is  not the engine, but is the gearbox clutches, which will fail prematurely from “overload” (which is what the manufacturer will call it when he denies the warranty claim).

Because the Hughes 38s standard Atomic 4 engine was mounted below the salon floor (if the optional Volvo Penta saildrive was fitted it was installed below the companionway stairs) repowering with a diesel must be carefully planned so that the new engine will still fit without having to modify the salon floor. It is very common to see Hughes 38 boats which have been repowered with an engine that doesn’t fit, and which required the salon floor to be either raised or notched, creating a tripping hazard (ie the Perkins installed in “Wild Card” was too high, and so the salon floor has a 3″ high box around the engine). The Universal M35-B engine and 2:1 ZF-10 gear fitted to Water Lily just fit underneath the floor only after I cut away the front of the hatch at the front of the engine. (Universal diesels are marinized Kubota diesels.)

The other problem with repowering is that the Hughes 38 with an Atomic Four had a heavy two-part water-jacketed exhaust pipe running from the engine to the stern under the salon floor. By the time repowering takes place it will require replacement to ensure sea water doesn’t drip through a corroded hole in the inner pipe and flow back into the new engine… which will destroy it. Most repowers include replacing the water-jacketed exhaust with a water-lock muffler, usually mounted underneath the gearbox and/or propeller shaft, and rubber exhaust hose, rather than fabricating another heavy jacketed exhaust pipe. If a water-lock muffler is installed an anti-siphon valve must be installed in the water hose from the heat exchanger to the exhaust elbow water injection fitting at the same time. Because the exhaust hose run is so long due to the centre-mounted engine, the hose diameter should be as large as possible to reduce back pressure. After the new engine has been installed the exhaust back pressure should be checked… it must not exceed 1.5 psi at full load.

Water Lily also has an Aqua-drive constant-velocity joint drive with the thrust taken by a heavy plate glassed to the hull, and different engine mounts than the ones supplied with the new engine by Universal in order to get the engine to fit. I also had to grind some of the fibreglass away from the inside of the hull and cut the ends off the engine mount supports.

Also, Water Lily has an optional pulley installed on the end of the crankshaft which is used to drive a high-pressure water pump for the Aqua-Drive water maker. Some people use the optional pulley to drive a large water pump which can be used as an emergency bilge pump and a high volume fire fighting pump.

There are lots of other issues with repowering, but this is an introduction to some of the main ones.

Rob

And another email:

Jon

Some… don’t understand the difference in horsepower between a direct drive Atomic Four (no reduction gear, or a 1:1 V drive) and an Atomic Four with a 2:1 Paragon reduction gear (or 2:1 V drive).

Many sailboat owners also don’t understand that horsepower is a function of torque X rpm, so the propeller can limit horsepower if it doesn’t let the engine get up to its rated rpm (ie Atomic Four: 30 hp @ 3,500 rpm). They think that a bigger prop will let the engine turn slower at cruise speed, but what it actually does (besides lugging/damaging the engine) is lower the maximum rpm and therefore lower the maximum horsepower available from the engine.

A displacement hull boat (ie sailboat) cannot be driven past its calculated hull speed no matter how much horsepower is used. If it is towed past its calculated hull speed by a bigger boat it will start to zig-zag all over the place and either the tow ring or bollard will rip out of the deck, or the boat will suddenly dive under the water. That’s why whenever a sailboat is towed by a larger boat the owner should warn the tow boat captain not to exceed the smaller boat hull speed (ie around 8 kn for a Hughes 38), and should stand ready with an axe to cut the towline if the tow boat does suddenly start to go too fast (which often happens).

The maximum rpm the propeller on a displacement hull boat (ie sailboat) can turn before propeller cavitation becomes a problem is around 2,000 rpm.

If a direct drive (1:1) gear ratio Atomic Four engine (ie without a 2:1 reduction gear) is fitted it can only be revved up to 2,000 rpm. Over that the prop will cavitate badly. That means that the actual horsepower the engine is generating is limited to around 14 hp.

Screen Shot Atomic 4 HP Torque HP Curve Stevedore

14 hp is all the power needed for smaller sailboats, so many smaller boats have a direct drive Atomic Four installed, with a prop that limits the rpm to around 1,600 to 2,000 rpm. (Some smaller boats have a V drive, but the V drive ratio is 1:1, ie the Hughes 25 and other smaller models.)

If an Atomic Four with a 2:1 reduction gear (or 2:1 V drive) is installed, as in the Hughes 38, then the full rated rpm (intermittent rating, which means it can be used for a maximum of 10 minutes to get out of the way of a big ship) 3,500 rpm of the engine can be used because the 2:1 gear ratio will drop the propeller rpm to a maximum of 1,750 rpm, and so the engine will be able to generate its rated full 30 hp without the prop cavitating.

Rob

Screen Shot Atomic 4 Torque HP Curve