YANMAR PLEASURE BOAT ENGINES are designed for pleasure boat use. (look on the brochure) The average operating hours for a pleasure boat is 10 - 25% of a commercial sports charter fishing vessel, per year.

YANMAR manufacture a separate range of engines for COMMERCIAL marine use. Like their pleasure boat range they are not a truck, tractor, train or trolley bus engine, they are a purpose built marine engine.

YANMAR does not agree to, in any way, the use of pleasure boat engines for commercial use.

However it would be ridiculous to pretend there aren't any pleasure boat engines in commercial operation and I would guess that at least 10% of them are. Many failures occur because the engines are not operated at a level that compensates for extended high power running. Liken it to buying a rally car engine and putting it in your courier delivery van!

When driving a Jet Unit the thermal loads are higher as the engine is run at the top end of the rpm band to achieve the boat performance required. Expect a lower service life when attached to a Jet unit.

The advice that follows is given with the knowledge that the buyer didn't know, or didn't care that the engine was not designed for commercial use, by heeding this advice you can have a longer lasting engine.

If you want to operate an engine commercially it should be de-rated by the distributor, on a dynamometer, prior to delivery to you, the customer. This de-rating is at your expense.

If you need 230hp, buy the 315hp engine and have it de-rated to the maximum continuous rpm and horsepower. If the engine is already installed, have the dealer install a pyrometer in front of the turbocharger, and reset the fuel injection pump to reduce the TIT. ( turbocharger inlet temperature ) ( if you do it yourself any warranty will be invalidated )

Do not throttle stop the engine, it doesn't work. Piston, cylinder head and exhaust manifold failures will occur.

Reasonable operation can be worked out by calculating the amount of fuel used, per hour, against the theoretical consumption at maximum continuous rpm. Fuel usage should not exceed 30% of the theoretical consumption at maximum continuous rpm over a 6 month period.
Engines often used commercially are listed below with the horsepower and rpm at maximum continuous, theoretical fuel consumption at maximum continuous rpm and recommended fuel consumption over an extended period.

NEVER use 6LP-series, 6LY2-STE or 6CX-GTE(2) engines commercially as only YOU will pay !

It is important for best performance, fuel consumption and engine life that your engine has the correct PROPELLER.