Honda BF9.9d 2002, new water pump still overheats, head gasket?

[verno]

a previously unknown, to me, motor, 2002 honda 9.9 electric start with remote control, fired it up ran fine but no water flow and telltale not plugged. So i found and Replaced a badly destroyed water pump , made sure water tube was clear, installed new water pump and confirmed good flow to the thermostat and replaced the thermostat at the same time. All using service manual procedures. Afterwards ran it in a barrel, pees a good stream at all speeds, a little less at idle but stays steady. It will idle for about 10 minutes approx then sets off the heat alarm on the remote control. I can shut it off for a few seconds and start it up and it will idle again for about three minutes then sets off the alarm again. I can also shut it off, and restart immediately, at idle, and in about 2-3 minutes it sets off the alarm again and every time. but the telltale never falters.

I suspect, because of the first destroyed impeller. it had been overheated before i got it, Is it likely to be air locking due to a bad head gasket?

New information: i replaced the battery in my heat sensor tool. If i let the motor it stay at idle the temperature slowely and steadily riseses to over 200 and sets off the alarm. however if i throttle up, about 2000 RPM, a little bit just below 200 degrees, it will cool back down to 150 ish degrees and slowly rise again at idle. Again the tell tale remains a constant stream only slightly varying from idle to higher RPM. And the idle is a few RPM above recommended speed.

Is it time to pull the head and see what's blocked or if a bad head kasket?

 

[Sea Rider]

Re: Honda BF9.9d 2002, new water pump still overheats, head gasket?

Being a 11 year oldie, good time for a complete crankcase & head water passages clean, probably full of salt if used at sea and poorly flushed after use. Take advantage to clean, remove carbon build ups inside combustion chambers, pistons, torque new head gasket and that horse will spring to life...

Happy Boating

 

[mtodd101]

Re: Honda BF9.9d 2002, new water pump still overheats, head gasket?

Hi Sea Rider. Can you give me a ballpark figure on the cost of the services you suggest to Verno? I have the same motor except a 2003. Mine started sputtering and dying yesterday. Oil level is higher than the mark and smells of strong fuel. Thanks Matt

 

[isaksp00]

Re: Honda BF9.9d 2002, new water pump still overheats, head gasket?

Is it also possible a chunk of the destroyed old impeller worked its way into the cooling passages in the engine?