Divemaster1
Well-Known Member
Right guv... picking up this one late, but want to say one thing ....
The two-stroke Detroits are not as bad as people say ... actually was the only real alternative for anyone speccing a proper boat in the 80's.. Reliable, and great engines. The Tyne Class lifeboats have the V6 onboard and they're still going strong. Admittedly fuel hungry, when out of tune, but which engine is not? lack of understanding is all I can fathom as the reason why people think they are thisty...
Fuel consumption of mine, early 80's are stated as 200g / Kw h, which is very comparible with same age 4 strokes. The latest generation V...s state something along the lines of 185 - 190g / Kw h, so how someone without the knowledge can state that they are more thirsty than the equivialent 4 stroke, is beyond my understanding.
Service cost .... well dirt cheap actually ... most parts in the 71 and 92 series are interchangable, and the volume of the machines around makes parts cheap.. Replacement injector for £ 55 and filters for about £5 is not expensive. The engines have replacable cylinder liners, so in darn close to forever lasting even if you run them down big way... got samples of both the 71 and 92 series which have run more than 40,000 hours and still going strong with plenty of life left. Ask any fisherman, or commercial operator about the engines, and you'll get a true picture.
Find a nice boat and get the engines checked over by a good dealer. Even if the engine(s) are past their best, you can have a complete re-build for approx £1,800 foe each cylinder. Subtract that from the cost of the boat, and you'll have a great deal. You can inspect the cylinders in situ here without much hassle, which you cannot witha 4 stroke. Yes a lot of mechanical bits here, but no electronics, so bullet proof when given a bit TLC ... (good oil, OK fuel and enough air)... Over propping is a problem, but that is the previous owner wanting a bit more, and not the engine's problem. When testing a boat with DD's, do ensure that you get full Load RPM... if not the boat is overpropped and engines are running on overload. Take note of engine serial nos and call DD service outlet & you'll get original performance spec & accessory fittings from DD for free.
There is a lot of metal in these engines, so heavy in comparison to newer stuff, but the hull will be designed to take it, so cannot see any big deal there.
Good luck, and enjoy the sound ...
I love the sound of my Detroits in the morning .....
The two-stroke Detroits are not as bad as people say ... actually was the only real alternative for anyone speccing a proper boat in the 80's.. Reliable, and great engines. The Tyne Class lifeboats have the V6 onboard and they're still going strong. Admittedly fuel hungry, when out of tune, but which engine is not? lack of understanding is all I can fathom as the reason why people think they are thisty...
Fuel consumption of mine, early 80's are stated as 200g / Kw h, which is very comparible with same age 4 strokes. The latest generation V...s state something along the lines of 185 - 190g / Kw h, so how someone without the knowledge can state that they are more thirsty than the equivialent 4 stroke, is beyond my understanding.
Service cost .... well dirt cheap actually ... most parts in the 71 and 92 series are interchangable, and the volume of the machines around makes parts cheap.. Replacement injector for £ 55 and filters for about £5 is not expensive. The engines have replacable cylinder liners, so in darn close to forever lasting even if you run them down big way... got samples of both the 71 and 92 series which have run more than 40,000 hours and still going strong with plenty of life left. Ask any fisherman, or commercial operator about the engines, and you'll get a true picture.
Find a nice boat and get the engines checked over by a good dealer. Even if the engine(s) are past their best, you can have a complete re-build for approx £1,800 foe each cylinder. Subtract that from the cost of the boat, and you'll have a great deal. You can inspect the cylinders in situ here without much hassle, which you cannot witha 4 stroke. Yes a lot of mechanical bits here, but no electronics, so bullet proof when given a bit TLC ... (good oil, OK fuel and enough air)... Over propping is a problem, but that is the previous owner wanting a bit more, and not the engine's problem. When testing a boat with DD's, do ensure that you get full Load RPM... if not the boat is overpropped and engines are running on overload. Take note of engine serial nos and call DD service outlet & you'll get original performance spec & accessory fittings from DD for free.
There is a lot of metal in these engines, so heavy in comparison to newer stuff, but the hull will be designed to take it, so cannot see any big deal there.
Good luck, and enjoy the sound ...
I love the sound of my Detroits in the morning .....
