Cracked head on 9.8 Merc?

[JimbadMerc]

Hi All: Newbie here. Have a 9.8 which dumped the impeller. Fixed that. Had some problems getting the tell-tale to show a stream of water -- that ***seems*** okay, now. However, it runs pretty rough. I changed plugs -- and while watching it run with the cover off, I see water bubbling (and boiling) around the lower spark plug.<br /><br />Head cracked? From what I've read on this forum, is it likely (possible) that it's a water jacket leak? Any suggestions? Please.<br /><br />Many thanks,<br /><br />Jim

 

[alcan]

Re: Cracked head on 9.8 Merc?

Hi Jim<br />Your Merc has an integal head, it is part of the block and can not removed. What you see, that looks like a head is a water jacket cover. It sounds like you need a new gasket for this.

 

[JimbadMerc]

Re: Cracked head on 9.8 Merc?

Hi Alcan: Thanks so much for your help. Quite relieved about the head...will start looking for a gasket on Monday.<br /><br />Best,<br /><br />Jim

 

[JimbadMerc]

Re: Cracked head on 9.8 Merc?

Hmm. We took off the water jacket and installed a new gasket. This seems to have fixed the leak by the plug, but the tell-tale only shows a steam, not a stReam. I'm really miffed, because the engine doesn't run right either. Seem to fire up and take off well -- then, it lost power, almost as tho it wasn't getting fuel.<br /><br />Any suggestions appreciated.<br /><br />TIA,<br /><br />Jim

 

[corm]

Re: Cracked head on 9.8 Merc?

Hi Jim,<br />The upper water tube seal has a plastic collar on it that melts shut when you get the motor real hot. The replacemnt is fiber. I would pull the powerhead and replace it. Also the pieces of impeller get pluged in the exhaust manifold plate. If you take this off you will be able to see how bad if at all the pistons are scored from being too hot. If they arn't scuffed then you can look elsewhere for your poor running problems.<br />Oh-ya sometimes the water outlet in the block melts shut too, where the telltale hose hooks to.

 

[JimbadMerc]

Re: Cracked head on 9.8 Merc?

Hi Corm: Thanks for the response. I will have a look. <br /><br />Jim