2005 50tlrd 2 Stroke - Problems running WOT

[defiant1]

Runs fine at low RPMs but once wide open for more than about a minute the alarm sounds and the engine bogs down (shakes) and slows down. I have to run it at idle for about a minute till the alarm goes off. Then it will run wide open for about a minute and then the same thing happens.

Is this an overheat alarm, a bad oil level sensor, or is it a fuel filter issue? Any help would be appreciated.

[99yam40]

I would put my money on the overheat

[defiant1]

Just did the impeller 5 hrs ago and water stream is fine. Do I need to look at the the oil injector?

[99yam40]

impeller is not the only thing that causes over heat, and the tell tail is not the best indicator for proper water pump flow, just says it is pumping water

[TownsendsFJR1300]

Have you ever pulled the thermostat and checked for salt build up in the block/water jacket?

Is the engine used in salt water and if so, flushed regularly with fresh water after use?


Some interesting reading:

http://www.yamahaoutboardparts.com/f...g-th19434.html

[defiant1]

I replaced the thermostat this weekend and cleaned out the little bit of corrosion in the housing. Still had the same problems with the alarm and bogging down. Engine is not used in salt water.

So if the water pump is working but there may be a circulation/blockage problem, where should I look?

The post about the Rydlyme was very interesting. Thanks Townsends!

[Brettoes]

Had the exact same problem on my 50 HP motor, turned out to be blocked cooling passages from not flushing out the motor after use(previous owner).pulled thermostat and exhaust covers off and it the passage ways were full of salt and mud
Vinegar flushed it, tub of 10 litres of vinegar and 50 litres of water, flushed it about ten times over a day and the crap that came out of it was pretty amazing, after flushing,pulled motor apart, exhaust covers, head and thermostat, and it was clean as a whistle. Problem solved, no more alarm.