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I have a Yamaha PX150TLRX.
A long time problem w/ cooling that we (son and I) finally think is solved. There is a 1/2"? pipe thread x 1/2" hose barb fitting that screws into the base of the lower engine base underneath the engine block. We found the fitting pinched partially closed and think this restricted water flow. Engine would start fine but overheat shortly. Thermostats were checked and water pump replaced to no effect.
The new fitting arrived and we attempted to install. It does not want to thread into the engine threaded hole. I thought I must have received the wrong fitting (lost bag it came in) and bought another w/ exactly same dimensions confirming the fitting is the correct part. Fitting size is very close and will start to thread but then twist out. I found what I think is a 1/2" NPT malexmale fitting and it will thread in snugly.
From measuring the dimensions, I think the replacement fitting is British Standard Pipe (BSP) 1/2" x 14 threads/in. I found a chart of US and British NPT standards and this seems closest dimensions (thread OD 20.8mm) and thread pitch is close (as near as I can measure).
Any ideas what could be the problem? I'm tempted to source a NPT 1/2" NPT x 1/2" hose barb, but am concerned about operating temperature of this fitting. I suspect temps will be in the 120-140F range, if this is cooling water from the engine, but it may be cooling water intake path. Anyone know?
thanks
A long time problem w/ cooling that we (son and I) finally think is solved. There is a 1/2"? pipe thread x 1/2" hose barb fitting that screws into the base of the lower engine base underneath the engine block. We found the fitting pinched partially closed and think this restricted water flow. Engine would start fine but overheat shortly. Thermostats were checked and water pump replaced to no effect.
The new fitting arrived and we attempted to install. It does not want to thread into the engine threaded hole. I thought I must have received the wrong fitting (lost bag it came in) and bought another w/ exactly same dimensions confirming the fitting is the correct part. Fitting size is very close and will start to thread but then twist out. I found what I think is a 1/2" NPT malexmale fitting and it will thread in snugly.
From measuring the dimensions, I think the replacement fitting is British Standard Pipe (BSP) 1/2" x 14 threads/in. I found a chart of US and British NPT standards and this seems closest dimensions (thread OD 20.8mm) and thread pitch is close (as near as I can measure).
Any ideas what could be the problem? I'm tempted to source a NPT 1/2" NPT x 1/2" hose barb, but am concerned about operating temperature of this fitting. I suspect temps will be in the 120-140F range, if this is cooling water from the engine, but it may be cooling water intake path. Anyone know?
thanks
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