55hp 2 stroke yamaha thermostat

[Advocatus]

Hi guys

Im new to boating and a complete novice when it comes to outboards. I have bought a surf ski boat with 2 x 55 hp 2 stroke 2 cyl yamaha's probably 1976 or 1978 models. I have replaced the impeller on one of the motors due to the "tell tale" not pushing out enough water and it seems that the engine is heating up a bit. The replacement of the impeller did not completely solve the problem and it seems that there might be some blockage in the system e.g. sand and/or debris.

Someone suggested that I should open the thermostat housing and clean it and flush the cooling ports (system) from the thermostat side with a hose. My problem is : Where is the thermostat housing located on the motor and is it possible to flush the system with a hose from there?

[boats.net]

Don't have any information on that model, the 55hp models here in the US had thermostat on top of cylinder head.

[Advocatus]

Thanks for the reply.

[surfcaster]

I'm a novice too. The ONLY way to go is to purchase the correct factory service manual. I have 2 outboards (Yam and Honda)and could not have imagined doing any work to them without the manuals. The manuals were worth every penny.

For sure could not have done it without these types of forums.

[Skyking711]

I just bought a online manual 6039002-Yamaha_1991-1996_2hp-250hp_Outboard_Repair_Manual_Improved It does not include the carbs that are on my motor so I don't really need it.