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Burnt rubber smell from motor

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baba_bluey

Regular Contributor
"Went out Mon. morning. Starte

"Went out Mon. morning. Started boat, and a couple minutes later, i could smell a rubber burning smell. Could see some smoke coming out of engine box. Shut it down a tried again. Same thing. All gauges looked good but i did notice the water temp. gauge climbing a little faster than normal. Right away i'm thinking waterpump in outdrive.(bay waterwas only 50 degrees) So i dropped the lower unit and checked the waterpump. Everything looked fine to me. Only other thing i thought of was the engine coupler. Nothing looked burnt or rubbed through insde the engine box. But it was a smell like a car tire burning. Any thoughts on what it could be?"
 
"Ayuh,...

Either the Couple

"Ayuh,...

Either the Coupler,...
Or the Belts spinning on a stuck Pulley.....

What motor,+ drive,..??
What was the outside air Temps,..??"
 
"Hey Bondo, Motor is a 1980 47

"Hey Bondo, Motor is a 1980 470 mercruiser. I believe the out drive is a MC-1(same year) No belts on motor. It was around 32-35 degrees. Went out around 4:30am. Someone said it could be the voltage regulator. I sure hope not. Just replaced that, stator, and new balancer. But that would be more of aq electrical smell. This was definetly a burnt rubber smell. All i know is they are slamming stripers out there, and i'm sitting home scratching my head."
 
"Ayuh,.... Being a 470,... I&#

"Ayuh,.... Being a 470,... I'm not much Help...

I'd Guess that I would probably go Light it,+ Look for Exactly Where the smoke is coming from....

If it's from the Aft end of the motor,...
It's pretty much Gotta be the coupler..."
 
"If its a coupler, your drive

"If its a coupler, your drive and prop won't be turning under load. And as Bondo suggest, look for a stuck pulley and the belt slipping across it. Sounds like a coupler."
 
"Are you sure the winter drain

"Are you sure the winter drain cocks are all closed? Just checking - have been there and done that! And there is coolant in the captive water system?

Soon as you start the motor put your hand on the exhaust elbow at the back end of the manifold. Unless you feel cold water there PDQ, shut it off. If the impeller is good then there's something plugged up in the water cooling system. That water passes first through the voltage regulator - check flow there. Had an impeller go bad and almost set the exhaust bellows on fire due to no water. That scared me. I always check that elbow every start - even installed a low pressure alarm on the dash so I'll know instantly if flow ceases during operation.

If your alt or reg is shot come back - there is a cheaper fix - replace with a belt-driven marine alternator with built-in v reg, one wire. Easy to do. Good luck. JW in Dixie"
 
"Started boat on Sat. Everythi

"Started boat on Sat. Everything seems to be ok. Did not know at the time, but my girlfriend had put both batteries on to put down outdrive.(was very cold that morning)So when i started motor, it was running on both batteries. Now i'm wandering if something is hooked up wrong."
 
"Well, found problem. Warren h

"Well, found problem. Warren hit it on the nose. Went about 2 miles off striper fishing. One throwback. So we decided to head into the back bay. fished for about an hour, and for some strange reason, i decided to lift engine box just to take a peak.
uhoh.gif
There was water up to the bottom of the harmonic balancer. Quickly hit on bilge pump manually. While it was pumping out, i could see water coming in from the exhaust bellow. Got back to the dock ok. So i guess the bellow got to hot, or cracked. Gonna take it apart this weekend. Thanks for all the help and opinions."
 
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