Serpentine belt shredded

[msballin]

Good afternoon -

Here's the skinny on last nite. Will try to keep it short. Warmed up engines as usual to 168 and departed for 20 minute cruise. Heard a single alarm beep from the area of the system monitor panel (which I thought odd as I had to shut its breaker in the main bilge panel off after it shorted out and kept constantly sounding). While under way I noticed the starboard engine voltage at just above 12 which normally registers a bit over 14 while running. Decided to return to port and power the engines down to see if they would start up. All was fine and voltage returned to normal while running. Next thing I know there's white smoke coming from the starboard exhaust port accompanied by a burning rubber smell. Powered down both engines, donned life jackets and called coast guard. In the interim smoke dissipated along with the smell. Sea tow brought me back to my dock where I was able to open the hatch and discovered the shredded belt. Apparently, the belt must have been on its way out and the alarm was sounding because of that? Not sure.

Question: I noticed the temp gauge last reading before powering down around 185. Curious if I could have done any damage. And as well, is there a protocol for how often the serpentine belts should be replaced.

Thanks in advance.

Cap Mike

 

[scoflaw]

More than likely one of your accessory pulleys froze up. Belts can last a very long time. My 10 year old belts look like new

 

[BillK2632]

Probably the water pump. Like Scoflaw said, belts can last a long time on a boat, I replaced mine at 10yrs just because it made me feel good - kept the old one as a spare it looks fine. If it is in fact the raw water pump, there are a couple of options for re-buiding or replacing those pumps. Unfortunately it's not going to a fun job on that boat due to access - not particularly hard, just hard to access.

 

[dpvandy01]

185 shouldn't damage your engine. I lost the belt on my port engine this season. Turned out it was due to my circulation pump. Changed that and all is up and running. Check your pulleys for wobble

 

[2000SR380]

in 2000 you should have a MPI engine management system with accessible trouble codes. Any of your buddies with a Rinda Code scanner or similar can look at what codes were present when the alarm went off. You mentioned a lot of "white smoke" from the starboard exhaust", but you did not say of you were low on coolant. The worry is that a coolant temp gauge stops working if there is no coolant. White smoke is water, or coolant, in the combustion chamber or being super heated in the exhaust. Frozen or rusty Pulleys can shred a serpentine belt pretty fast, so I am onboard that the 'shooter' here is a bad water pump, or possibly something else with a pulley run by the shredded belt. Get ready for some boat yard YOGA.

 

[msballin]

Just now to the engine room to find what I believe to be the tensioner pulley gone. Any idea other than normal wear and tear that would cause this to happen? Thx much for all of your input. Greatly appreciated.

 

[msballin]

Good call, Scofflaw. Tensioner pulley gone. Any idea what could cause this? Thanks

 

[msballin]

Thank you Billk2632. Mechanic due today. Water pump changed at beginning of season. Good idea to replace after overheat?

 

[scoflaw]

Thank you Billk2632. Mechanic due today. Water pump changed at beginning of season. Good idea to replace after overheat?

Make sure all your pulleys turn. Probably just the idler, they do fail. I'm sure your water pump is just fine, it wasn't even turning during the overheat.

 

[msballin]

dpvandy01..good info. Thx.

 

[msballin]

Great info. and thx once again

 

[BillK2632]

I think you are probably ok on the water pump. Once the tensioner pulley gave out everything that is run by the belt (raw water pump, PS pump, alternator) would have stopped also. You started to overheat because the belt wasn't turning the pump. Based on your year (2000) there was a problem with the plastic tensioner pulleys, yours probably was never replaced -- Mercruiser might supply the parts free of charge because at one point that was a warranty repair. Check the other engine, it might be on it's way out also.

 

[msballin]

So...here we go again. While just underway and throttlin up to 3200 rpms I smell rubber burning and hear a "roar". I look back and see white smoke from my port exhaust. Immediately shut engine down as the needle on the temp guage hit 225. Water was flowing fine from side exhaust while warming up prior to departure, coolant level was perfect (I never leave the dock without checking all fluids). Arrived back on starboard engine and discovered serpentine belt shredded. Upon inspecting this morning (engine way to hot to get near yesterday) all pulleys seem fine. Raw water pump replaced two years ago and had only 60 hrs on it. Mind you, this happened just two years ago and the culprit was the plastic tensioner pulley. New pulley was installed along with belt and alternator. Kinda stumped here as to what may have happened. Mechanic to visit this Thursday. Though my curiosity has me spinning. Any thoughts? Thanks as always