2000 90 HP Mercury Holes in block from corrosion

[bojango541]

Hello all,

I picked up a 2000 90 HP Mercury outboard for 350 bucks. Its got good compression on all 3 cylinders, good spark, and starts up and seems to run good. The catch is there are 3 holes in the block next to the cylinder head, which appears to be from corrosion from saltwater that circulates to cool the motor. theres no water getting into the actual cylinders. The holes are decent sized, about the size of my pinkie fingernail. I patched the first two up with jbweld and ran it for a while today on muffs and it seems to be holding. I just patched the 3rd one today and am currently waiting for it to cure. I originally bought the motor to part it out on ebay, but now my current plan is to put it on my bass tracker. Anybody ever patch a block with jb weld before? You guys think it will hold up, or is it bound to fail? Anything else on the motor I should worry about corrosion wise? I don't have a lot invested in the motor so I figure its worth a shot

 

[Texasmark]

With the compression area sealed off/ not leaking into the joint, you have a good chance of making it work. The expansion and contraction will be minimal, the cooling water flow and cooling water pressure are a no brainer. Main thing is hygiene, surface prep....lots of little surfaces for adhesion....good sanding with 100 grit, and time for a complete cure; I'd give it 48 hours at room temp at least. I know that's a long time but you do want it to hold don't you? I never had a failure on any type of repair I have made with JB weld and I have repaired some unusual marine and farm parts. I would think that this application is a benign task for it's capabilities. My last engine was the 2002 90 triple looper. Fine engine and loves the top end of the recommended range and beyond. I usually ran 5600-5800 at WOT and that's how I usually ran, unless it was too windy. My Avatar is that engine on my last boat.

 

[flyingscott]

Put pics up

 

[bojango541]

No Title

Not pretty....figured I'd put it on thick

 

[Texasmark]

Looks good to me.

That's a water jacket cover, not a head. If the engine had a removable head, there would be 3 parts and 2 gaskets.....engine block, gasket, removable head casting, gasket, water jacket cover casting. You only have 2 parts and 1 gasket.....engine block, gasket and water jacket casting. With 10-15 psig max, water pressure at WOT, you aren't about to disrupt your repair.

 

[bojango541]

No Title

Somewhat unrelated question. Can anyone tell me what this is?? Its above the top cylinder and the hose goes out the front of the motor.

 

[bojango541]

anyone?

 

[Texasmark]

Looks like a battery return (-)connection. Never saw such. Usually the battery cables come with the engine when new and enter on the left side (Port) looking at the engine with the wiring harness to the control box. Black - bolts to the engine block as that cable is attached, and the Red (+) bolts to the ⅜" input stud on the starter solenoid......that stud is used as a 12v distribution point besides being the input to your starting system. The other end of that pair of cables bolts to the crank battery.

 

[bojango541]

Definitely not a battery cable. It is a rubber line/hose with what looks like some sort of plastic quick connect fitting on the end. The small wire is only about 10" in length and looks to hook up to a wire harness

 

[sprocket911]

It looks like a quick connect for freshwater rinsing. You rinse without running the motor.

 

[yzf125]

It looks like a quick connect for freshwater rinsing. You rinse without running the motor.

+1 on the rinse

 

[bojango541]

That makes sense. Thanks!

 

[bojango541]

Patched all 3 holes up with the jb weld and finally got around to mounting the motor on the boat today. Ran it on a hose for a while and no apparent leaks from the block and it ran great. So far so good. Gonna drop it in the water this week and hope for the best!