Marinised diesels are usually based on an automotive (car) engine and have a few things added on to allow them to operate in the marine environment.
They are usually lighter weight, more compact, less costly and spare parts are more readily available/cheaper than standard "marine diesels".
Marinised engines have freshwater cooling, either by a saltwater/fresh heat exchanger on the engine or a "keel cooler" outside the hull. As a result the engines walls/housing can be allot thiner and lighter than marine diesels, as very little internal corrosion occurs.
Kubota (Japanese) diesel engines have a very good reputation and are used in industry and agriculture ashore. If they are marinized properly, they make for reliable and economic propulsion at sea. Spare parts are readily available and are more cost effective than pure "marine diesels"
Nanni Marine diesel engines have a kubota base motor. They are made in France and I've heard that they are reliable, have quality long lasting parts and can supply everything from propellor to controls. The 29HP "N3.30" has a 3 cylinder 1123cc engine and runs at 3600rpm maximum, peak torque is 2600 rpm. It's size dimensions are not too big leaving more room inside. They have keel cooling option. It runs a 12V 120A alternator, mechanical gear box and maximum 15 degree propshaft angle and weighs in at 145kg.
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| Nanni N3.30 |
Nanni also has a larger 37HP "N4.38" with a 4 cylinder 1498cc engine. It runs slower at 3000 RPM maximum and has a wider useful torque curve. It has larger size dimensions and is heavier than the 29HP but is rated for more usage and more hours per year than the 29HP.
Beta Marine (UK) might be a good option. The Beta 25HP has a 3 cylinder 898cc Kubota , weighs 113kg and often swings a 14" diameter 3 bladed prop (but it's best to supply boats specifications for correct prop) . The Beta25 is very compact and serviceable parts (oil filters, electrics etc) are easy to access.
At least a couple of wylo's have Beta Marine engines fitted. There is a distributor/service center in Sydney, Beta diesel Australia.
Witchards Marine (Sydney, Aust) make WM28. , 3 cylinder Kubotas with larger 1123cc displacement, larger size dimensions and swing a slightly larger prop. (The WM22 is a 898cc but 22 horsepower might not be enough for a wylo 35?)
For those with technical skills and a flair for DIY, car engines can be marinised. Nick used his van's petrol engine. Heard of a VW golf diesel installation too.