engine stalls - The Hull Truth

paulb · 06-09-2008, 04:54 AM

One of my engines 2004 yamaha 225 four stroke stalls at very low speeds at just about idle more often then I would like. At first I thought it was the alarm only with the engine still on but I know for sure that it is definatley stalling. Other than this stalling problem the engine is running perfect. Do you have any suggestions ?

Thank you in advance for your help, I really appreciate it.

A1 Outboard · 06-09-2008, 06:42 AM

A lot of things can cause the motor to stall. With today's fuels, injector gumming is very common especially if the motor is not used often. The state of tune of the motor is critical also as is the idling temperature if the thermostats are not working right. The synchonization of the throttle plates on each cylinder can make or break a good idle, too.

The first thing to do is a complete tune up and checkover and filter replacement. Make sure the boat's fuel system is OK without any air bubbles in it at either high or low speeds. Have a leakdown test performed on each cylinder to make sure the valves and rings are not carboned up which give a poor idle. A rich dose of Ring Free can help in that case. Read the label about shock treatment.