After we ran the James run I noticed the port engine sounded "different"; very slight tickety-tick-tick-tick! Then when we got home I removed the therm. housings to clear the impellor pieces and clean up & paint them and while doing that decided to also paint the valve covers. So, after I put it all back together, nicely painted Mercury silver and red, the test run I noticed that tickety-tick-tick became a slight knockety-knock!! Not loud just barely noticeable. Then, I remembered seeing a very small amount of white oil in that valvetrain....no big deal at the time, but now it's making me wonder?? Blown head gasket?? Or do I just need a valve adjustment? Since the over-heat issue @ the start of the James run was so brief, and she ran so good for the run @ back on Sunday, I thought I was in the clear...could that overheating have caused a problem that would show up after 4hours run time?
I posted over in the gen. discussion area too; but got a few wise-cracks! What should I do first??
Thanks,
Spilman

This will sound odd, check your exhaust gasket. Mine sounded like what you describe. I found I had a blown exhaust gasket. Hope you do too vs. real issues!!

Hope thats all it is Chris. How many hours?

400hrs on the button...I did replace the exhaust gasket...No luck there. It is most likely a "tuliped" valve or a rocker problem...John, What should I do first? Or what is the next least amount of work($$$) that is possibly the cause?

And, BTW, when I say what next I kinda need specifics; I'm a G.C. NOT a mechanic!

Thanks....

Don't know if you got them but check the exhaust flappers, in the pipes that stop water from entering, they can make a heck of a knocking sound too if there worn. Hope you get it fixed, are you in NY?

Not yet..we were planning on leaving Thurs. but now w/this problem I'm not sure. If I can't get it fixed we will just bring the deck boat....will let you know.

Any luck Chris?

Chris , Sorry for not getting back to you sooner. How is the oil pressure? Damn, If I had time I'd cruise down and take a look.

A quick way to check for a blown head gasket is by checking compression on the cylinders on the side of the engine from which the noise is coming. If there is a difference in compression between pistons (Like 10psi) you may have a head gasket issue. When an engine overheats it shouldn't introduce water into the engine unless something is damaged (gasket or metal). What type of exhaust do you have? It could be possible to damage a riser and introduce water into the engine through an exhaust valve.

Stainless Marine Exhaust system...and it's fine. The cylinder with trouble is the 3rd back on the inside of port engine; closest to the risor. It seems to me when I had the compression test done 2 yrs ago that cylinder was 160 & all the rest(both engines) were 190-205psi....that is where the tick-knock is and I'm pretty sure its a bad valve or rocker....its def. in that valvetrain. After 400 hrs, most of which is over 4000revs since I've owned the boat(3owner boat!), it may be time to pull the heads.
So, NO More AT for this season!!!!!!!!!!!!I have a Deck boat, I need to get back on the slalom and get my ass in shape anyway!
Thanks for all the suggestions...Keep em' coming.
I'll be up @ the 1000Islands run this weekend.....actually riding in an Outerlimits in the run.I'll try to get some pics...