Rut Ro - blew up my motor. Looking for some advice

[Port Monster]

The folks at another boating form that deals with Hulls and Truths suggested that this may be the forum for my questions!!!

My Mercury 225 EFI bit the dust. The top port cylinder looks like it threw a rod. The oil reservoir is full and all of the other pistons are oily - doesn't seem that it was a lean run condition. I want to try to fugure out what the problem is so I am looking for some thoughts on what would have caused this to happen?? Any ideas would be aprreciated!!!!!!

So somehow the wrist pin let loose and the **** hit the fan. Piston was jammed against the spark plug, the rod bent and started to rattle around in the cylinder and caused the cylinder walls to disinigrate. The thing that baffles me is that I see no blueing of any parts. The bearing disinigrated but the rollers are not blue, the rod is not blue, the head is not blue and the cylinder walls are not blue. I just do not see a overheat condition in there which makes sense since I was up on plane and under 4000 rpm for less than a minute when it started to loose power and started knocking. Sooo - any thoughts - PLEASE

I have a spare block but want to figure out what caused this before I switch everything over (Before Memorial Day!! )

Thanks!

 

[Maxz695]

Re: Rut Ro - blew up my motor. Looking for some advice

A lack of oil wouldn,t cause it to overheat(Setting off the temp alarm). Lack of oil will Burn things up in a minute. The oil pump may have went.Why the alarm didn,t sound may be a bad warning alarm itself. This is just some suggetion as to how or why this may have happened.

 

[Monte1961]

Re: Rut Ro - blew up my motor. Looking for some advice

And sometimes parts just break!

 

[wifisher]

Re: Rut Ro - blew up my motor. Looking for some advice

And sometimes parts just break!

I agree, but that piston looks like it was lean.

 

[j_martin]

Re: Rut Ro - blew up my motor. Looking for some advice

Bad fuel injector on that cylinder. Lean burn took out the piston. When rings started hooking the ports is when the **** hit the fan. The phrase "lean" doesn't refer to the oil, but to the fuel.

The quickest way to make an anchor out of a V6 is to starve it for fuel.

 

[Port Monster]

Re: Rut Ro - blew up my motor. Looking for some advice

I thought that I would have seen some sign of melting on the top of the piston in a lean burn situation (unforntunately I have experience starving an engine of oil but have not had a true lean problem before) but this piston has no melting. The holes and other damage are from when the rod let loose and the piston rammed up against the plug and cover and there is no sign of actual heat on the piston (blueing, etc.) But, it is clear from the damage on the cylinder wall that the piston had taken several strokes before the rod let loose - so the rings may have started to go causing the whole thing to crap out as j_martin suggests.

With that said - I think that a fuel injector is a place I have to look. Is diagnosing a fuel injector problem on an EFI difficult?

 

[j_martin]

Re: Rut Ro - blew up my motor. Looking for some advice

Another thing they do sometimes is let go of the ring locator pins. Then the rings turn till the ends hook the ports.

That's why the high per guys put the pin in from the top then weld the hole shut.

It's ugly fer sure.

 

[Faztbullet]

Re: Rut Ro - blew up my motor. Looking for some advice

J hit it right on, it leaned out. Possible causes are: injector(my bet), chipped/broken reed. You can send the injectors off to Tony and Linda at Brucatosvs.com to have flowed/tested/cleaned and balanced. The locating pin for top ring is still in place as it can be seen in picture at the 9 o'clock position. You are going to have to have it resleeved as the bridge is broken on the transfer port at the 7 o'clock position, also check the other cylinders especially #1 and #3 as debris will transfer thru the exhaust. Also checl the webbing at the bottom of the cylinder bore as these are know to suffer cracks from debris under piston on down stroke.

 

[Port Monster]

Re: Rut Ro - blew up my motor. Looking for some advice

Just an update - I pulled the injectors last night and sent them to Brucatos for analysis, cleaning and syncing!! I am going to inspect the reeds once I get them pulled from the motor.

 

[Port Monster]

Re: Rut Ro - blew up my motor. Looking for some advice

Another update. Injectors all tested rich. From the looks of it there is no chance that they leaned out the motor. So off to some more thinking and diagnosis!

 

[Port Monster]

Re: Rut Ro - blew up my motor. Looking for some advice

Just another update - removed the powerhead last night. Not too bad of a job; only made one mistake. Thank God I have a donor outboard!!