Mercruiser 260 exhaust elbow ????

[Alumarine]

Hi there. I'm at the lake helping a friend troubleshoot an overheating problem.
It's a 1977 260hp with raw water cooling.

My manuals are at home of course.

We've removed the thermostat and it still runs at 200.
Impeller and water pump are new.

We took the exhaust elbows off and notice that there is an aluminum blocking plate that blocks the water flow on the elbow.

What's the deal with this plate?

 

[Bt Doctur]

Re: Mercruiser 260 exhaust elbow ????

How many hoses connect to the exaust manifold .How many hoses on the therm housing.
I notice the riser has a fitting ,so the block off may be correct.

 

[Alumarine]

Re: Mercruiser 260 exhaust elbow ????

Thanks for the quick reply.

There are 2 hoses going to each exhaust manifold end.

1 hose going to each elbow

There are 6 hoses on the thermostat housing.

 

[RickJ6956]

Re: Mercruiser 260 exhaust elbow ????

My manual is on the boat. Rats. However ...

Got twin engines? Could this be the counter-rotating engine? If so, verify that the hoses on the fresh water pump are reversed (which is correct).

On the thermostat housing there is one intake, one bypass, and one circulating for each side -- total of six.

 

[Alumarine]

Re: Mercruiser 260 exhaust elbow ????

Just the one engine.
Going to fire it up and see what temps we hit without the blocking plates.

 

[jtybt]

Re: Mercruiser 260 exhaust elbow ????

Check water flow from hoses and blockage in water outlet in risers.

 

[Alumarine]

Re: Mercruiser 260 exhaust elbow ????

Check water flow from hoses and blockage in water outlet in risers.

We've checked the flow coming out of the thermostat block and it's good.
Will check flow out of risers.

thanks

 

[Alumarine]

Re: Mercruiser 260 exhaust elbow ????

Thanks for the all the help.

Captain decided to take it into the shop tomorrow.