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Qi own a Beneteau idylle 1150 in the Mediterranean equipped with a 1995 Volvo Penta MD2030 (29hp, 1,400hrs run time). no problems so far with the engine but as diesel fuel is changing over the years i’m getting advice from other sailors to the effect that the cheap diesel i typically use from the French supermarkets will clog up injectors and valves and once this ‘dirt’ is in you can expect expensive repairs. i have been told to:
Run the engine on max revs regularly
Add a diesel injector cleaner to my fuel regularly
Fill up with premium fuels from time to time. is any of this advice correct for my boat? Ludo Van Senten, by email Stu DavieS replieS:
The VP MD2030 is a good engine and the only issue that I have heard about is the exhaust elbow becoming blocked with carbon and salt.
According to the manual the max speed for the engine to give its rated horsepower output is 3,200-3,600rpm. In real life however most people only use about 2,200rpm and there is the rub. A diesel engine is at its most efficient when running at its designed speed for its rated horsepower and what happens is the lower speed allows build up of carbon and salt crystals in the exhaust elbow.
I have seen recommendations that the cruising speed of the MD2030 should be 300-500rpm lower than the maximum speed
– but if we followed that then we’d all be zooming around at hull speed.
Yanmar actually recommends putting its engines in neutral every two hours and racing it flat out six times to blow the carbon out.
So to answer your question about engine speed, run the engine as hard as you can to clean carbon deposits out, and check your exhaust elbow every couple of years for blockage.
If you continually use low speeds then give it a prolonged blast for about 10 minutes on full throttle every now and again.
Going to the fuel additive question. Our biggest problem is the fuel bug which is caused by water in the fuel tank and bugs growing on the interface. Unfortunately the addition of biofuel in to our diesel has not helped the situation, using road fuel, don't forget that up to 5% bio addition is now mandated by EU regulations. I personally remove the fuel level sender in my fuel tank to gain access and use a Pela suction pump to remove any condensation water in the bottom of the tank and any bug residue. I also use Marine 16 bug inhibitor at every fill up.
Using injector cleaner additive? I don't see the need. And as for ‘cheap’ supermarket fuel being dirty, it’s an urban myth. The turnover of the product means supermarket tanks are continually being filled with fresh diesel from the refinery and are often the best source of clean fuel.