Tohatsu

[kawarider]

I have a 2008 25 Four stroke and at long idle the alarm and red light comes on steady.The water coming out of pee hole is very hot but it is peeing water.When you run the boat down the river it runs fine and will idle for around 3 minutes then the alarm sounds.Does anyone have any ideas?

 

[pvanv]

Re: Tohatsu

Year is irrelevant for servicing a Tohatsu/Nissan OB. However, model/serial is critical. I assume you have an MFS25B (fuel injected 3-cylinder) motor. See p25 of your owner's manual (you can d/l a copy from http://www.tohatsu.com/tech_info/manuals.html).

A steady warning lamp and buzzer indicates either low oil pressure or overheat. Since the problem crops up after idling for a few minutes, and the water is very hot at the telltale, you are probably overheating. That would typically be an under-performing water pump, a stuck thermostat, faulty overheat sensor, or corroded cooling passages (unlikely in a motor of your vintage). Is the telltale stream very strong, or just a dribble? If the latter, the water pump is likely not pumping well enough at idle.

I would have your dealer check the cooling system. The 25/30B has a data connector, and your dealer can read the historical data out of the ECU to accurately diagnose exactly what the motor's running conditions have been. If the thermostat has failed in the 3-yr warranty, the repair will be at no charge to you. Of course, the water pump is supposed to be inspected/serviced annually, and is considered a normal wear component, so if that is the problem, the service will be at your expense.

 

[TOHATSU GURU]

Re: Tohatsu

Tohatsu Corporation' of Tokyo, Japan, was founded in 1922. It manufactures and sells outboard motors, pleasure boats, portable fire pumps, small fire trucks, pumps for construction and drainage, refrigeration units for transportation and also does real estate property management in Japan..Tohatsu Corporation' of Tokyo, Japan, was founded in 1922. It manufactures and sells outboard motors, pleasure boats, portable fire pumps, small fire trucks, pumps for construction and drainage, refrigeration units for transportation and also does real estate property management in Japan.

The company was originally named Takata Motor Research Institute, and manufactured railcars. Research and development of high-speed, portable engine generators and radio-controlled generators began immediately and were brought to production in 1930. During the 1930s and 40s, Tohatsu consolidated its product line and moved its corporate office to Tokyo. In 1950, production and sales of motorcycles began. 1955 brought aggressive growth to Tohatsu. Capital increased to 150 million yen and production on a new line of engines started. Sales offices were established in Fukuoka, Nagoya, Tokyo, Sendai and Sapporo. Dealers were set up throughout Japan.

I have a drivers license. I can drive a car.

 

[440MOPAR]

Re: Tohatsu

check the water outlet in the center of the casting below the cover latch mine was stopped up with dirt dobbers and ran mine hot.this is wear the water exits the head if no water can get out no cool water can get in. i just learned this yesterday and it may have cost me an engine

 

[pvanv]

Re: Tohatsu

check the water outlet in the center of the casting below the cover latch mine was stopped up with dirt dobbers and ran mine hot.this is wear the water exits the head if no water can get out no cool water can get in. i just learned this yesterday and it may have cost me an engine

While it is possible to have that condition, it is rare. The MFS25B does have an idle port (to reduce exhaust restriction at low speeds), but 90-plus percent of the cooling water exits via the prop hub.