Did I throw a rod?

[rustyscrew]

I have a mercury 1400 (1978). It has been running beautifully with very few problems. I was running at 2/3 throttle today on the way home from trip and I suddenly heard a loud knocking or rattling coming from the engine. I think there was also a loss of power. I immediately powered down and shut her off. I used the kicker to get back to the harbor. I tried starting the engine at the dock so I would could hear the sound better and it sounds like a rattling inside the engine ( although its hard to place where its from) . It sounded like it would start, but I didn't go that far because I could hear the noise from the starter turning it over.

Any ideas? In particular, any easy checks first before I go ripping it apart?

Thanks!

 

[rustyscrew]

Re: Did I throw a rod?

year was 1978. not sure where the sunglasses came from!

 

[jimmbo]

Re: Did I throw a rod?

Look to see if there are any holes in the block. Turn the flywheel by hand, make sure ignition is off but pull all the plug wires to be sure it won't start. You might be able to feel if a bearing cratered. Pull the sparkplugs to see if any are damaged or have self destructed and shine a light into the hole and see if the top of the piston has ding marks. Also check the top of the flywheel for cracks, it is just a piece of sheetmetal, like a flexplate

 

[rustyscrew]

Re: Did I throw a rod?

Thanks. that is some great advice!

 

[Chris1956]

Re: Did I throw a rod?

Rusty, Do a compresion test on the motor. I will bet you find a cylinder or two (like number 1 and 3), with no compression.

 

[rustyscrew]

Re: Did I throw a rod?

Chris,
I will check the compression. what is it that you think broke?

 

[Chris1956]

Re: Did I throw a rod?

Rusty, In my experience the rings need the most lube and cooling. I am guessing that you motor suffered from an overheat or lean fuel condition. This causes the rings to score the cylinder. Now it may be a rod, but you should be able to tell by removing the plugs and turning the flywheel. It it turns smooth, the rods are good.