Water leaking near top plug #1 inline 4 50hp 63' 500

[PlayDoh]

I just got this boat, and I changed the impeller and theres water pissn out right along the edge of the spark-plug opening. NOT from the cylinder, but from where the "Head" meets the plug sleeve.

I'm not sure of the marine terminology and I'm still learning about the basics. I have a good grasp of mechanical engines and know how to turn wrenches

I'm not even clear on what a "Power head" is. On one side of the motor is the carbs and on the complete opposite side is the plugs, which doesn't jive with my understanding.

The "head" (cast iron piece where the plug holes are in) or w/e its called is where the leak is comin from. I suppose it could be only the gasket, but if its like anything else I own it will be cracked.

It runs fine otherwise, which I found shocking :^ I was like "Shut it off!! SHUT IT OFF!!" lol then I thought "how could it even start if it was coming out of the cylinder? It will Idle for 10 mins and I quickly checked it in gear. I got it in a rain barrel.

PS anyone got some schematics for Merc O/B's? preferably old merc d Just some exploded view pics so I can learn some part names and inner workings.

 

[WillyBWright]

Re: Water leaking near top plug #1 inline 4 50hp 63' 500

It overheated. Check your compression. That's probably why they sold it. The water jacket cover warps when that happens. You probably just need to replace that gasket. You'll just about have to chisel it off, but remember that you're scraping aluminum. Be careful.

 

[emckelvy]

Re: Water leaking near top plug #1 inline 4 50hp 63' 500

The gasket's probably just dried up and old. Very common to see leaks from the water jacket area. Use caution when removing the bolts, if they don't want to come out easily don't force them. Apply heat and maybe a penetrant such as PB Blaster.

A quick-and-dirty way to fix the problem semi-permanently would be to thoroughly clean the area with a solvent such as lacquer thinner then seal up the leak with Automotive Grade non-copper-type silicone sealer (RTV). This'll stop the leak long enough for you to be able to run the motor and further evaluate whether or not it's worth doing a lot of labor-intensive work to. For an even better seal leave the spark plug in and pack RTV around the spark plug. So, better put in some new J4C plugs first!!!

You may find the info you need at the www.oldmercs.com site or here: http://www.dougrussell.com/partscatalog/collections/index.cfm?fuseaction=collectdetails&colid=07

Cheers........ed

 

[PlayDoh]

Re: Water leaking near top plug #1 inline 4 50hp 63' 500

Hey, thanks a ton guys. Great info, and I'm soo glad its likely just a gasket. Take care