water leak behind and below the engine when running on miffs 3.0

[friendly_jacek]

no, the brass plug was found. i just didn't picture it. the rust is from the block. i'm going to take off manifold today to see the condition of it. the riser looks good to my untrained eye.

thank you all for response.

 

[alldodge]

no, the brass plug was found. .

Still looks like it rusted out. Happen to boat in salt water?

 

[friendly_jacek]

salt water? only a few times. mostly fresh water and flushed and winterized religiously. low hrs. the problem was the boat sat unused a lot. i'll post more pictures this PM.

 

[friendly_jacek]

this is after cleaning loose rust. will a new plug seat properly in this?




this is the plug in question. chewed by the flywheel.




took the manifold off. everything looks decent. are these passages good enough? should i take the side caps off to see insides?



riser before cleaning. good to reuse?

thanks again!

 

[Scott Danforth]

clean the hole with a wire brush in a drill....... like your trying to remove the evidence of a crime scene or the stripper glitter from your trip to vegas

then using permatex #1, liberally coat the sides of the core plug and the block hole and drive the plug in

use a file to clean the gasket surfaces on your elbow.

 

[Sea Rider]

Having the motor out of the boat, wouldn't it be better to replace all water plugs for new ones if having more than the shot one, same as when restoring a car motor ?

Happy Boating

 

[alldodge]

The plug to the right looks like steel

 

[friendly_jacek]

The plug to the right looks like steel

i noticed that. not sure what it means. i bought it brand new and it has been never repaired prior to this.

 

[tank1949]

harringtondav, thanks for ideas, will try and report back. I'm pretty sure Bt Doctur is right, and I'll have to overhaul the rig, but it doesn't hurt to try things before I rip it apart sometime this winter.

It is hard to really see but just by chance is exhaust pipe near where you suspect leakage? With V8s, we refer to them as Y pipes. They USUALLY connect to MC gimbal housings via 4 3/8" common threaded bolts with special 12 point heads. They are a pain in the butt to get access to unless you remove motor. I have replaced 3 Y-pipes in my life because of leaking due to corrosion. If your boat is used in saltwater, and you pull motor, please be sure to examine this pipe for corrosion. It may not be your issue now, but it will if used in saltwater. Good luck!

 

[Bt Doctur]

The plug to the right looks like steel

that is the plug for the camshaft,

 

[alldodge]

that is the plug for the camshaft,

Agree, but its steel ... and yes I know there is oil on the other side

 

[achris]

Agree, but its steel ... and yes I know there is oil on the other side

Pretty sure GM never changed any of the camshaft bore plugs, inlines or V8s.... I've never seen anything but steel in that location...

Chris.....

 

[friendly_jacek]

Much overdue update on the project. it was a lot of work and it took me several weekends to finish. i took the engine out for the first time, so i had to learn a lot of things and proceeded slowly. after replacing the failed freeze plug and close inspection of the whole thing, i decided there is no other damage to the engine. running it in the backyard and near 3 hr river trip confirmed that. after carb rebuild it runs better than it did before. no water in oil or any other places it doesn't belong.

the best i can understand what happened, the boat sat a lot unused with water in the block. i only drained water before winter. the brass plug caused galvanic corrosion at the place it was pressed onto the iron block. eventually the corrosion weakened the fit and the plug fell out. that is supported by tons of the rust internally in the vicinity of the freeze plug.

anyone else seen anything like this? from now on, i'm going to drain water after each run.

thank you all for your help!