4.3 Mercruiser noise at low rpms

[taylor1990]

I have a 1993 chaparral with a 4.3 mercruiser that I just recently purchased. The first day that I put the boat in the water it ran fine with no issues. about a 30-40 ride. the next day after about an hour the boat started to surge so I went ahead and cut the engine off. After about 10 minutes with it off I started the engine, put it in gear and it started to make a marble/ metal clanking noise. Not a knocking sound. Best I can do on the sound descriptions. It only does this at lower rpms in gear but then quits once it reaches higher rpms. The surge issue im not so worried about. I think its just due to gas or something simple. Help would be appreciated.

 

[Bondo]

Re: 4.3 Mercruiser noise at low rpms

I have a 1993 chaparral with a 4.3 mercruiser that I just recently purchased. The first day that I put the boat in the water it ran fine with no issues. about a 30-40 ride. the next day after about an hour the boat started to surge so I went ahead and cut the engine off. After about 10 minutes with it off I started the engine, put it in gear and it started to make a marble/ metal clanking noise. Not a knocking sound. Best I can do on the sound descriptions. It only does this at lower rpms in gear but then quits once it reaches higher rpms. The surge issue im not so worried about. I think its just due to gas or something simple. Help would be appreciated.

Ayuh,.... Welcome Aboard,...... Only at lower rpms,..?? Up to 'bout What rpms,..??

What Temps was it runnin',....
Low to No water flow from the impeller can Fry the shutters, 'n they'll click at idle,...

Have ya Checked anything,..?? oil levels, 'n condition,..?? motor,..?? drive,..??

Spark plugs look Ok,..?? check the compression,..??