Volvo Penta Overheating

[annapolisdan]

Here is my problem. Have older Volvo Penta 4.3L V-6. Just had manifolds and risers replaced along with new impeller. Put her in the water this weekend for first time. After about 20 minutes at idle/no wake speed, noticed strong burning rubber smell. Opened engine hatch and port side manifold/riser/exhaust tube/elbow was smoking and VERY hot and making popping and hissing sounds. I believe exhaust tube was source of burning rubber smell. Went to idle speed and limped back to dock but port side components were still smoking upon return. Starboard side components were generally cool to the touch. Also, temperature gauge was not reading anything.

Any ideas? Seems like it might be a thermostat issue? Engine also stalls at idle speed after about three or four minutes. When out of the water with ear muffs, plenty of water was moving through the system and out the exhaust, so I don't think it is a blockage issue at the intake. Impeller is new. I welcome all comments. Thanks.

 

[annapolisdan]

Re: Volvo Penta Overheating

Just an update: starting pulling hoses from the t-stat to the manifold. Pulled the hose running to the "hot" side of the engine and could find no evidence of any water. So in my mind it either was totally blocked or had such little water running through it that the hot engine vaporized it immediately. Maybe that was the "smoke" I saw coming from the manifold/riser/exhaust hose assembly? Next step is to keep moving backwards "up the chain" to the t-stat, water pump and intake tube for evidence of blockage. Any thoughts are welcome.

 

[Don S]

Re: Volvo Penta Overheating

Did you ever check the raw water pump impeller? When was it changed last. And, what is an OLDER VP. Got a year, or better yet a model number?

 

[annapolisdan]

Re: Volvo Penta Overheating

Hi Don S. Impeller was just changed a few weeks back. Engine is a 1994 4.3L v6 with the GS/SX drive. Pulled the thermostat this afternoon and the port side outlets were almost completely clogged with scale/rust. Think I found the culprit as starboard side was much clearer.