Yanmar 3GM30 info

[Rob_Webb]

New boat is 'perfick' except previous owner deceased hence difficult to get answer to some handover questions e.g. engine fuel consumption. Anyone know? For info, seems to cruise happily bout 2-2500rpm (5.5-6kts) and fast cruise feels bout 3,500 rev but rev counter will actually whizz right up 4000rpm for a few mad moments (by then doing 7.5kts)! Any idea on fuel consumption at these kind of settings?

Also, what's the power? Name of engine suggested to me bout 30hp - but little label on engine says 24hp - is that conservative?

Other imperfection is no fuel tank gauge or dipstick or even engine hour meter - so howmIgonna keep track of fuel level..... fit a gauge I spose?

Thanks

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[snowleopard]

3gm30 is officially 27hp.

fuel consumption: i get around 2.5 litres/hour at 2750 rpm but i'm a little over-propped so you may get better than that.

rev limits are 3400 continuous, 3600 max. if underpropped/in neutral the governor will limit it to 3800

any details you need, PM me. i'm always happy to email the odd page from the workshop manual.

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[toad]

I seem to use about 2lt hour at 2300rpm.Continuous rating 24hp at 3400 rpm,max 27hp at 3600rpm.

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[timentide]

I have just bought a workshop manual for my 3GM30 from www.workshopmanuals.co.uk, it is on CD. They are very efficient and for a cost of 10 pounds a good buy. You will find this 240 page manual full of useful info on your engine.

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[Rob_Webb]

Awesome. Thanks for your help guys. NM

.

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[ShipsWoofy]

Not wishing to argue with what you say, but only the latest generation 3GM30's are 27hp. The older ones are around 23-24hp as rob says. Yanmar eaked out an extra 1hp per cylinder in their GM range around 10 years ago I think, hence the 1GM10 is now 9hp....9*3=27hp.

Sounds like you have an older generation engine Rob, surprising as your boat looked pretty new to me, or at least in extremely good condition then.

Here are some details from the workshop manual:

Model 3GM30
Type: Vertical 4-cycle water cooled engine
Combustion Chamber: swirl pre combustion chamber
No cylinders: 3
Bore x stroke mm(in): 75 x 72 (2.95 x 2.83)
Displacement litre (in³): 0.954 (58.21)

Continuous rating output (DIN6270A)
Output crankshaft speed Hp/rpm (kW/rpm): 24/3400 (17.9/3400)
Brake mean effective pressure kg/cm² (lb/in²): 6.66 (94.71)
Piston speed m/sec (ft/sec): 8.16 (26.77)

One hour rating output (DIN6270B)
Output crankshaft speed Hp/rpm (kW/rpm): 27/3600 (20.1/3600)
Brake mean effective pressure kg/cm² (lb/in²): 7.07 (100.54)
Piston speed m/sec (ft/sec): 8.64 (28.35)

Compression ratio: 23.0
Fuel injection timing degree: b.TDC18±1°
Main power take off: At flywheel side
Front power take off: At crank shaft V pulley side
Direction of rotation - Crankshaft - Counter clockwise viewed from stern
- Propeller shaft (ahead) - Clockwise viewed from stern
Lubrication system: Complete enclosed forced lubrication.
Starting system: Electric and manual

Lubricating oil capacity (rake angle 8°)
Total litre (in³): 2.6 (158.65)
Effective litre (in³): 1.6 (97.63)

Engine weight with clutch (dry) Kg (lb) : 130 (287) <font color=red>Raw water</font color=red>
Engine weight with clutch (dry) Kg (lb) : 138 (304) <font color=blue>fresh water</font color=blue>

Gearbox
Model: KM3A
Constant mesh gear with servo cone clutch (wet type)
Lub oil: SAE# 10W-30, CC class
Lub oil cap: 0.3 ltr
Dry weight: 11.0kg (24.3 lbs)

I do not understand this graph. Maybe someone can enlighten me, but my 1GM10 uses about 1/3 litre per hour cruising. So it would figure that the 3GM30 will use approx 1 ltr per hour cruising at 2800 rpm.

Hope this helps

insomniacs rule!


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[snowleopard]

thanks for the graphs. for a 3gm running at 2700 rpm fully loaded it is producing 20hp and consuming about 200 grams of fuel per horsepower per hour or 4kg per hour, roughly 3 litres per hour.

i think that condition would require it to be loaded up with a big prop so you need full throttle to get those revs, so not a realistic situation. though it makes my 2.5l/h look quite reasonable.

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[ShipsWoofy]

aaaah, grammes, I was wondering how the graph was representing gallons, I knew it wasn't, but I did not consider for one moment it was describing weight.

Thank you for that, what weight have you used for diesel?

Would anyone like my to upload the 1 and 2GM graphs?

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[Rob_Webb]

Hi Jools - thanks for all that, very useful. And yes, it sounds like my engine is the previous generation of 3GMs (24hp variety) - the boat and engine are both 1992 so at 12yrs old just outside your 10yr cut-off for the 27hp changeover.

You're right though, the boat is in very good nic and doesn't look or feel her 12 yrs of age - previous owner was an aircraft engineer and he kept it pretty tip-top.

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