Cracked block- External 'How To'

[trihull59]

Just thought I would post up my recent findings. I have a OMC 3.0 L that I recently discovered has a decent crack along the block underneath the manifold. It ran fine with no water hooked up then when I had done all the work I needed to, to the boat and engine I hooked up some muffs and started the engine. I discovered gushing water coming through the side of my motor so I took off the manifold to find the pictures below.

Note: I had the engine get up to around 180' F to allow me to make sure that with the engine warmed up it was an external crack only.

I used Marine Tex gray which was rec. by a local marine shop.

Step 1 Clean and sand down surface. I used a dremel tool to grind/sand along and inside the crack.

Step 2 Wipe down surface with a solvent.

Step 3 Mix proper amount of marine tex

Step 4 Apply Marine tex

Step 5 Wait approx 24 hrs for the epoxy to harden

Step 6 Test

My motor is running great with no water in oil and or pistons. Only use this method after making sure the crack is an external crack only.

Here are some pictures

 

[Xesvuli420]

Re: Cracked block- External 'How To'

Thats an awesome fix. Good luck with it! I hope it holds.

The reason I'm posting this is because today I have the same motor, and I un-winterized my boat today. I hooked the muffs up, turned on the water, and cranked her up. It ran great, but while I was sitting there I looked back at my engine cover and noticed antifreeze running all over my floor board. I immediatly thought it had cracked over the winter, so I lifted the cover up and noticed the water was coming from the same manifold you removed.

I actually got lucky tho... on the bottom side of that manifold is this rubber grommet thing that has a bolt that tightens squishing it tight. I assume its just another way to drain water, but somehow, it had gotton blown out, and all the watter from my muffs were gushing out that hole. After digging around in my hull I finally found it, and popped it back in.

Scared the sh** out of me though cranking it for the first time this season only to see water rushing in!

 

[Frozen]

Re: Cracked block- External 'How To'

Just a quick question, why were your running it off the muffs with no water?

 

[cannonfodder]

Re: Cracked block- External 'How To'

Bad lookin' crack! Hope it holds for you.

 

[fishrdan]

Re: Cracked block- External 'How To'

It ran fine with no water hooked up....

How long? You probably fried the impeller in the lower unit.....

 

[Frozen]

Re: Cracked block- External 'How To'

How long? You probably fried the impeller in the lower unit.....

That was my thought also.

 

[trihull59]

Re: Cracked block- External 'How To'

Didnt have the outdrive on my boat when i ran it without water and it was only about 20 secs