1999 Yamaha 225 OX66 overheating issues

[soundwave15]

I am having issues with my motor overheating on a Fisherman 222. I am going through the typical checklist of issues it could be. When running water up through the fresh water flush fitting and have the thermostat covers removed, water is not even making it up there. Is this a sign that the water jacket may be clogged or am I missing something?
thx

 

[DennisG01]

Try running the engine and do the same test.

What did the impeller and housing look like when you replaced it?

 

[soundwave15]

Try running the engine and do the same test.

What did the impeller and housing look like when you replaced it?

I have, same thing, though intermittent. Impeller and housing seemed ok. I am getting water through the tell tale, though not quite as fast as I used to.

 

[SkunkBoat]

Overheating in the water or in the driveway?

 

[mjm1957]

Make sure the poppit valve is not partially hanging open.Water will still flow out the tell tale but not fill up the exhaust cover and the block. Had this exact problem yesterday on my brothers 250 OX66.There is also an updated poppit valve kit for these engines.

 

[seasick]

As Skunk said. Is it overheating in the water or on the hose and muffs?
If in the water when does it over heat, at speed and load or at idle. If at idle in the water does the alarm clear if the boat is sped up?

 

[soundwave15]

Make sure the poppit valve is not partially hanging open.Water will still flow out the tell tale but not fill up the exhaust cover and the block. Had this exact problem yesterday on my brothers 250 OX66.There is also an updated poppit valve kit for these engines.

That is my next step, I do have a new poppet valve on order. The updated one looks totally different than the original. Is this the one you used?

 

[soundwave15]

As Skunk said. Is it overheating in the water or on the hose and muffs?
If in the water when does it over heat, at speed and load or at idle. If at idle in the water does the alarm clear if the boat is sped up?

Pretty much everywhere. On muffs, in the water, at idle, and sometimes at high speed. It’s intermittent, making it more frustrating.

 

[mjm1957]

Yes I put the updated kit in my 99 OX66 225 and my brothers. Be careful when you change the seat, it can easily be pushed into the exhaust cover if your not careful.

 

[seasick]

It could be a bad thermo switch. One thing I might do is use an infrared thermometer to measure some reference temps before it over heats and then quickly after it overheats. Removing the cowling makes measurements easier but just measuring the pee stream temp may help you determine if the engine is actually overheating or if its a bad sensor/sensor wiring

 

[seasick]

That is my next step, I do have a new poppet valve on order. The updated one looks totally different than the original. Is this the one you used?

A bad poppet valve van explain overheating at idle or at speed but not if you alarm at both.
A spun impeller could explain everything. uou would have to tpull the lower unit to check that