79' SRV 260 w/ TWIN 470's, anything I am missing........

[Fordiesel69]

Got the boat home, installed new batts, fresh oil, fresh 50:50 coolant, lower unit impellers, lube, trim fluid, and made sure blower, bilge pump, and electric is good. Anything else to do before a sea trial? Boat is unknown to me, and don;t want to blow anything up.

 

[mwph]

Twin 470's in a 260?

 

[dpmulvey]

How old are the manifolds and risers? Have you run it on muffs to see if there is raw water flow. Bring a laser thermometer (Harbor Freight ~$25) and take temps of the riser elbow. Have you checked the Thermostat functionality.

Don't forget to put in the drain plug.

 

[Fordiesel69]

Well good news and bad news, the port engine & drive are great. Started first try and idles like new. Engine sounds like new also, drive shifts perfect. Bad news is the starboard engine has a coolant leak on the front left side if viewed from the pulleys. Cant; even find where the leak is........ And the exhaust manifold gasket leaks on cylinder #2 which means cracked manifold, or just a bad gasket. Who knows. Otherwise that engine runs good also but needs a starter refesh.

 

[berth control]

That coolant leak is a big deal. It's leaking from a seal on the cam, you need to pull the motor and have the cam redone and put a new seal on it. It's a real bummer. Mine started leaking a couple years ago, but I just put a jar of "K-seal" in the coolant tank and that took care of it. My thinking was to put that stuff in and then replace the motors in a year or two, but it works so well that now I just top off the tanks every year and add some more stop-leak. I know it's not the "right way" to do it, but I figured that as long as it stops the leak, I might as well run the motors until they blow up, but that doesn't seem to be in the near future.

About the exhaust manifold leak, hopefully it's just a seal because the manifolds on these motors are SUPER expensive. I had a cracked manifold on one of my motors and ended up just buying a used running motor for the manifold only.

These 470's are not good motors. The only thing worse than a mercruiser 470 is a boat with 2 mercruiser 470's! :smt021

That being said, I have gotten quite a bit of use out of mine and once I got the bugs worked out they really run pretty good.

 

[Fordiesel69]

That coolant leak is a big deal. It's leaking from a seal on the cam, you need to pull the motor and have the cam redone and put a new seal on it. It's a real bummer. Mine started leaking a couple years ago, but I just put a jar of "K-seal" in the coolant tank and that took care of it. My thinking was to put that stuff in and then replace the motors in a year or two, but it works so well that now I just top off the tanks every year and add some more stop-leak. I know it's not the "right way" to do it, but I figured that as long as it stops the leak, I might as well run the motors until they blow up, but that doesn't seem to be in the near future.

About the exhaust manifold leak, hopefully it's just a seal because the manifolds on these motors are SUPER expensive. I had a cracked manifold on one of my motors and ended up just buying a used running motor for the manifold only.

These 470's are not good motors. The only thing worse than a mercruiser 470 is a boat with 2 mercruiser 470's! :smt021

That being said, I have gotten quite a bit of use out of mine and once I got the bugs worked out they really run pretty good.

Would this "K- Seal" not only block the heat exhanger core, but plug other stuff up as well?

 

[berth control]

It hasn't on mine. I'm not saying it the "right fix", but it worked for me. I just have a hard time justifying pulling a motor and basically rebuilding it because there is a bad seal. I figured that if I pulled the motor to do the seal I would just rebuild it any ways, so there was not a lot I was out if it didn't work. Fortunately, it worked great.

Also, you should know that the seal will only leak when the motor is running, because then the camshaft is spinning. Therefore, you will not be able to find the leak by looking it over, or even pressure testing the system. That particular leak is common on these motors and a common source of frustration.

 

[jarhead]

It's not that bad of a job without pulling the engine as long as you have enough room for a puller and installer for the fly wheel. I use a piece of 1/2-20 threaded rod, 3 nuts and a spacer to install the flywheels instead of the mercruiser $195 tool. Lots of cursing the engineer(s) that designed the 470s every time I lift the hatch though.