Doogle
09-10-2007, 11:31 AM
Hi guys
I have a DT4 that I bought about 12 years ago and it has had little use. I am now trying to set it up as an auxiliary on my 14ft Clark as a backup to a 35HP Evinrude. The motor starts easily enough and idles just fine.
The problem is that the water coming from the "pee hole" is ok when cold but slowly decreases as the motor warms up. Eventually it just peters out to a wisp of steam - then a quick "kill" of the motor is the order of the day to prevent damage. This was never a problem before - the motor always pumped water well each and every time I used it.
So far I have replaced the water pump impeller, the grommet feeding water to the cooling jacket, the gasket from the power head to the drive shaft housing ( and cleaned out the entire water jacket in the whole process ).
The pump is working. A power drill on the drive shaft to the pump (when separated from the bottom of the drive housing) lower unit causes the water to bubble out of the pump's outlet. It doesn't spurt out very far but then again, the DT4 only has a small impeller in the pump so I wouldn't expect a gusher.
All water passages are clear - proven by using water from a hose and by the fact that it pumps when cool.
It seems to me that it could be a crack in the head "assembly" but I find that difficult to accept or the motor itself would not idle & run as well as it does. The whole of the cylinder bore casing is extended to become what would be the head in a normal auto engine.
I have tried compressed air into the spark plug hole with the crank held in the "firing position" and there are no bubbles coming out of the water jacket as far as I can tell. If I let it rotate until the crank is in the exhaust position, air bubbles freely from the base of the motor.
Has anyone experienced this scenario before ? What was the issue ?
Does anyone have an old DT4 in the junk pile that I could use to dissect and fault-find this one ?? I don't really want to discard it so some advice to help make it healthy again would be great.
Thanks in advance.
Doogle
I have a DT4 that I bought about 12 years ago and it has had little use. I am now trying to set it up as an auxiliary on my 14ft Clark as a backup to a 35HP Evinrude. The motor starts easily enough and idles just fine.
The problem is that the water coming from the "pee hole" is ok when cold but slowly decreases as the motor warms up. Eventually it just peters out to a wisp of steam - then a quick "kill" of the motor is the order of the day to prevent damage. This was never a problem before - the motor always pumped water well each and every time I used it.
So far I have replaced the water pump impeller, the grommet feeding water to the cooling jacket, the gasket from the power head to the drive shaft housing ( and cleaned out the entire water jacket in the whole process ).
The pump is working. A power drill on the drive shaft to the pump (when separated from the bottom of the drive housing) lower unit causes the water to bubble out of the pump's outlet. It doesn't spurt out very far but then again, the DT4 only has a small impeller in the pump so I wouldn't expect a gusher.
All water passages are clear - proven by using water from a hose and by the fact that it pumps when cool.
It seems to me that it could be a crack in the head "assembly" but I find that difficult to accept or the motor itself would not idle & run as well as it does. The whole of the cylinder bore casing is extended to become what would be the head in a normal auto engine.
I have tried compressed air into the spark plug hole with the crank held in the "firing position" and there are no bubbles coming out of the water jacket as far as I can tell. If I let it rotate until the crank is in the exhaust position, air bubbles freely from the base of the motor.
Has anyone experienced this scenario before ? What was the issue ?
Does anyone have an old DT4 in the junk pile that I could use to dissect and fault-find this one ?? I don't really want to discard it so some advice to help make it healthy again would be great.
Thanks in advance.
Doogle