Here the story:
Mariner (made by Yamaha) 30hp 2stroke outboard motor
Its overheating.
New impeller last summer I looked at it it looks new.
New thermostat last week.
Good tell tale its peeing fine.
Seems to idle ok but overheats when in gear running takes about 5mins.
Tel tale pressure seems to get weak just before overheat.
What the hell is wrong with this motor?
Motor yamaha 30elo 689 model early 90's
Harry Buttcrack
Favorite Answer
You probably should have had the water pump body and wear plate replaced as well as the impeller. a worn or distorted pump body or wear plate will cause low water pressure, which will lead to a slow overheat condition. Easy to diagnose- remove the thermostat and run the engine. If thye overheat condition continues, the problem is almost always with the pump. The only other possibility is an incorrectly seated water tube, either a damaged or missing grommet in the engine block.
Anonymous
First thing is did they replace the water-pump housing when they did the job or just the impeller?If only the impeller the housing could be melted and this would cause your problem. Next is there could be a piece of the old impeller stuck in the housing or somewhere else.You must removed your lower unit and check for this because there is nothing else that would cause your problem.Good luck.
Red
water pump is the problem if the pee stream gets weak. worn housing, worn impeller, impeller key missing, intakes blocked or clogged,water tube not seated properly.