What Happened to my Merc260?

[FingerLakesBoater]

I was under full power when the engine began to vibrate bad and smoke. I shut it down and noticed that the temp gauge was hot, it had been fine about 19 minutes prior. I restarted the motor and had vibration and only slight propulsion. Tried to limp back to the dock and lost all propulsion fast. Out of the water the prop still turns but not under load and under load a lot of vibration near the rear of the engine. What happened to my Merc? Is it something that I can fix myself? Any Help or suggestions would be appreciated. Thanks, Gus

 

[Bob_VT]

Re: What Happened to my Merc260?

Check your compression. You might have lost a cylinder or two. Absolutely replace the t-stat but I would fully check the motor first completely. It sound like a motor problem and not an outdrive problem.<br /><br />Bob

 

[Trent]

Re: What Happened to my Merc260?

Sounds just like you spun your coupler. Look on the back of the engine..DO you see "rubber dust". Spinning the coupler causes the temp to go up since the driveshaft is not turning the lower units water pump.<br /><br />

<br /><br />You have to pull the engine and the outdrive to replace the coupler.

 

[Walter]

Re: What Happened to my Merc260?

It sounds to me that perhaps the sea water pump (in outdrive) may have failed and you majorly overheated the engine. A very similar thing happened to my bro-in-law when a large plastic bag caught on his outdrive and plugged the water intakes. <br /><br />Check your engine oil for proper level, color, etc... You may want to pull and examine each spark plug. It's going to take a little investigation to determine the extent of damage caused by the overheat. I may be premature saying the overheat caused the engine symptoms you describe but that seems the most logical explaination.<br /><br />What year is your MerC?<br /><br />Walt

 

[Walter]

Re: What Happened to my Merc260?

I'll bet Trent has pegged your problem. After reading his post, I re-read yours and the symptoms you described. A coupler failure sure sounds like what you're facing. Bummer...that's a major job to replace. <br /><br />Walt

 

[FingerLakesBoater]

Re: What Happened to my Merc260?

Thanks for the advice guys and yes Walter I think Trent knows what he is talking about because he's the second person that told me that. It's definaltely a bummer since it's prime season. Anyway Trent thank you and one more question how hard of a job is it to fix the coupler? If I pick up a service manual should I be able to complete the job myself? I have never worked on a boat before this is my first but I have been working on cars and motorcycles for a long time so I figure I should be able to handle this with a little advice? Thanks Again Everyone, The Dry Docked Boater GUS

 

[Trent]

Re: What Happened to my Merc260?

Actually its not to bad..If you have some mechanical skills. You will need to remove the engine at least to gain access to the coupler. (about two feet). You can do this without removing the outdrive but I would pull it so you can check the alignment of the drive. 85 percent of coupler failures are due to inproper alignment. You will need a special tool to align. While you have the drive off grease the u-joints and driveshaft splines.(marine grease)

 

[flashback]

Re: What Happened to my Merc260?

I'll agree with Trent, one question, did the smoke smell like rubber?

 

[FingerLakesBoater]

Re: What Happened to my Merc260?

Trent, I checked the rear of the engine compartment and low and behold rubber particles!!! You nailed this one and I didn't even know that you could see the coupler on the rear of the engine. I looked it over and it doesn't seem like it will be too hard to repair it. I do understand that I will have to unbolt the motor to gain access and standing on my head for awhile too will be fun!! Thanks for the help and advice. I will let you know how I make out. Gus

 

[Trent]

Re: What Happened to my Merc260?

Check this link for parts...Cheapest I know of web page<br /><br />Trentcr@hotmail.com