Water leak from Powerhead Area Mercury 650 Thunderbolt 1970 redband

[chewbacca]

I bought the original mercury workshop manual and its great. Now i understand why you guys stress on buying a manual. Anyway im going to go ahead with removing the powerhead and i just realised im going to face problems with removing the bolts. And i have read whole heap of topics on the subject and have found one explaining to heat the screw up with a butane torch and then cool it down with WD40 by spraying it. We have this product which is called ROST OFF and i think its better than wd40 because its penetrates deeper and is a tiny bit corrosive. Anyway about the torch, I have this torch which is basically the cylinder butane tank and on the top it has the actual torch coming out ... I think its the one used by plumbers. Will this be fine or will i need to get a Butane/Oxy combo and a precision torch?..Anyway my problem is water is leaking out from the bottom of the water jacket cover. I believe that this is caused by a tiny puddle of water which always stays behind after use and it slowly ate through to the outside through the block. I was wondering is this repairable or will i have to use another block? I have another motor which i bought from a mechanic who came in with a problem with the LU but in the end traded in the whole motor.Thanks guys "_"

[The Marine Doctor]

Would it not be easier to move the gearcase from you old engine across to the other engine...rather than take all those bolts out?TMD

[chewbacca]

the other engine is a short shaft so yes i could just move the blocks over.. But i still have to see if the other block is alrite. I try to move the flywheel with my hand and it seems blocked.. I will try take out the sparkys and move it and see if that helps. The engine hasn't been used in a solid 5 years so maybe its just clunked up over timeWhat would be your recommended way of trying to turn over the engine by handWould it be wise for me to spray a ****load of 2stroke oil in each cylinder plug it in and turn it over with the battery or can i really screw things up?The reason i havnet thrown out my motor is because i really love it. Even with the water leak i have still gone off shore with it and it still hasn't let me down once. Apart from the first trip when i didn't clean the top carby and it spat fuel.So basically in short im going toSpray oil into the cylinders.Let it soak in overnightPut a socket wrench onto the middle nut of the flywheelTurn the flywheel by hand with the wrench?Can you recommend me to do anything different?

[The Marine Doctor]

I would most definately try to turn it over by hand before engaging the starter. If something is stuck...its not a good sign...but you do not want to make matters worse by the torque of the starter.TMD

[chewbacca]

ok good newsI got the motor unseized. Turns out it was probably rust..Every turn of the flywheel i make there is a distinctive clunk at one moment is that just the cam or something?Anyway on my original motor im having a really hard time in removing the bolts. I heat them up with a small hand held butane torch as hot as it can get (they don't get red hot) and spray RUST OFF around them for about 10 seconds. Some of it seems to get sucked in.Should i be using a Butane/OXy combo to get them red hot or am i doing enough already?

[The Marine Doctor]

A distictive clunk is NOT a good thing..the engine has no cam. You should hear nothing but the impeller turning in the housing and possibly compression being forced out the sparkplug holes.I might be wrong but I think a Butane torch is 1700 deg F I would think this is sufficient to heat up the bolts for removal.TMD

[chewbacca]

i see.Should they be going red hot?

[chewbacca]

oh yeah i found another interesting thing my other motor looks like the powerhead cover (water jacket cover thingy) has a sealer that is black all around it.. I think its the stuff you buy in the squeeze tubes?Maybe thats all i have to do on my original motor? Because it should fill the cavities caused by corrossion!

[The Marine Doctor]

This would be something I would have to see to comment on.TMD

[rockytop93]

have you done a compression test on your original engine? If its ok probably all you need to do is swap the water jacket with the one from the engine you bought. Get some new gaskets and put it together.

[chewbacca]

Original motors fine i have been using it since i got it but i finally have time to fix the leak Basically in the older motors these where metal on metal.. After a while the salt eats away the bottom because always a little stays back. And i was thinking of packing it with a gasket type material you find in toothpaste type tubes. There no chance in hell you can find a gasket of this size probably huh?The corrosion aint in the water jacket cover its in the block