Mercury 402 40 hp water in upper cylinder when running

[Phazer230]

Hi guys, I am working on a friend's old merc 402 40hp outboard and when it's running it is spewing water out around the upper spark plug, does this mean the block is cracked or is there other possible issues for this to happen ?

 

[jimmbo]

Likely a Leaky Water Jacket Cover Gasket and/or Warped Water Jacket Cover.
Seems to happen a lot on engines that get a little too Warm, too many times

 

[racerone]

Replace gasket as stated above.----Might as well do your friend a favor and replace water pump impeller.

 

[Phazer230]

Likely a Leaky Water Jacket Cover Gasket and/or Warped Water Jacket Cover.
Seems to happen a lot on engines that get a little too Warm, too many times

Hi thank you very much for your reply! Does this happen to be this in the photo as some are located on the rear of the engine where the plugs are aren't they ?

 

[jimmbo]

OK Sticker/Decal, is just an Engine Test Run was done at the Factory. Which on this engine, was about 50 yrs ago

 

[Phazer230]

Replace gasket as stated above.----Might as well do your friend a favor and replace water pump impeller.

Or

OK Sticker/Decal, is just an Engine Test Run was done at the Factory. Which on this engine, was about 50 yrs ago

So this is the water jacket area that may need attention? Thank you very much for your help !

 

[jimmbo]

So this is the water jacket area that may need attention? Thank you very much for your help !

Are the Spark Plugs there?

Here is my 84 115, getting the same repair

 

[Phazer230]

Are the Spark Plugs there?

Here is my 84 115, getting the same repair

No, spark plugs are not in the area I pointed too that's why I am asking, what I pointed to might be the exhaust portion

 

[Phazer230]

Are the Spark Plugs there?

Here is my 84 115, getting the same repair

This is what the 402 40 hp looks like then ?

 

[jimmbo]

Yep, that is the cover that is leaking if the water is coming out by the Spark Plugs. Hopefully you won't break any of the Bolts that hold it on. You will have to remove the Parts of the Cowl Support Frame(front and rear) to be able to tilt the Lower Cowl to access the bottom of the Jacket. You can see how I had to tilt it to gain Access.

 

[racerone]

Serial# is needed.

 

[Phazer230]

Serial# is needed.

Ok, I will get it for you

 

[Phazer230]

I am having trouble locating the gasket needed part number 27-854901 quicksilver I think

 

[hardwater fisherman]

Think they are NLA. Check EBay.

 

[Phazer230]

Yep, that is the cover that is leaking if the water is coming out by the Spark Plugs. Hopefully you won't break any of the Bolts that hold it on. You will have to remove the Parts of the Cowl Support Frame(front and rear) to be able to tilt the Lower Cowl to access the bottom of the Jacket. You can see how I had to tilt it to gain Access.

Yeah, I saw the Philips screws in the bottom, will do, thank you

 

[Phazer230]

Think they are NLA. Check EBay.

Thanks for the heads up, I have one coming

 

[Phazer230]

Gaskets came in today anyone happen to know the torque specs for the merc 402 ? 20 lbs good enough? And do you guys recommend ATV sealant on this water jacket cover gasket ? Thanks

 

[jimmbo]

20 inch lbs? I had better luck with the gasket installed Dry

 

[racerone]

The 1/4" bolts are in the order of 60 to 80 INCH LBS

 

[Phazer230]

I got the job completed and no more water leak, thanks everyone for the advice!