89 2.3 OMC Capri Upper Exhaust Manifold Gasket Leak

[MainiacMusic]

Hi all,
I just wanted to start off by saying I have been using these forms to help diagnos several issues since buying my first boat a month ago, so thanks for all the info.

Long story short I melted the exhaust Bellow when the intake hose came loose from the out drive. I had to remove the upper exhaust manifold to replace it. The metal gasket split in half and when I attempted to reuse it, it obviously failed, but it was worth the try. The exhaust was shooting from the gap. I bought some copper rtv gasket repair and reapplied the the gasket, now I don't see any exhaust, but my concern is that if there was a leak between the water jacket and the exhaust, how could I tell for certain? It appears to me that I have more exhaust then before, running on the muffs. Could it be watervapor? I don't want to take it apart unless I have to. I do have the correct gasket on the way but if the rtv is working then I won't disturb it.

Thanks,
Trevor

 

[Scott Danforth]

first, welcome aboard

second, if you ran without water, you burned every rubber bit in the exhaust. that is the elbow to down pipe tube, the flapper and the bellows.

third, with any new to you boat, make sure you do all the maintenance the prior owner didnt do. your boat is 32 years old and has three strikes against it besides its age. strike 1, its a late 80's bayliner, so you will have rotten stringers and transom. strike 2, its an OMC, strike 3, its a ford 2.3

your exhaust manifold most likely needs to be replaced (common issue with the 2.3) they are about $500. then you have the elbow to buy as well.

you cant seal that with copper RTV. you need a new gasket at a minimum. however most likely you need an exhaust manifold and elbow too.

 

[MainiacMusic]

Maybe I misspoke, or perhaps I don't understand. Why would the entire manafold need to be replaced? Are you suggesting the the mating surface is warped? What is the flapper? The gasket I'm referring to in between the manifold and the elbow. Should water be entering the exhaust stream at that gasket would it fall into the exhaust valves and foul the oil? Is there any way to tell for sure this is actually happening? What else should I be checking?

Thanks for your reply. I just recently replaced the plugs, wires and coil. I troubleshot an ignition issue. I found the issue with the water intake tube. Cleaned the carbourator. Repaired a damaged shift cable. I will change the oil and filter at the end of the season. Any other suggested maintenance? I appreciate your response.

 

[MainiacMusic]

Just an update and some clarification for those interested.

When I used the copper rtv, I did so without removing the gasket. The metal had split leaving half the gasket on the elbow and the other half on the exhaust manifold, except for a small chunk that stuck to just one side. I made sure to apply extra where this peice had stuck all to one side. I cleaned the mating surfaces making sure not to remove any gasket material. I applied, bolted down hand tight, allowed to harden for an hour and then torqued down. I repeated the tighten after running.

Today I ran the boat on the muffs for a while, the water vapor is no longer pressent. I'm wondering if I was burning off the remaining water and cleaner in the elbow when I initially ran it and reported a lot of vapor. The gasket appears to be holding. With a lot of reading and research I have found that obviously copper rtv isn't the correct solution for this, but I plan to try and finish the season and replace it with a real gasket next season. I checked two cylinders and the oil to make sure that water isnt being pulled back in at shut down, as vapor lock or hydro lock would not be a very pleasant issue to deal with.

I will be taking it out in the coming week, hopefully everything goes well.

 

[Scott Danforth]

You cant fix the gasket by schmutzing RTV on the outside.

Pull the elbow. You will find the mating surface has rusted away (common issue with OMFG 2.3 manifolds)

 

[kpg7121]

I know you're new to boating, I get it but one thing is for sure. Skimp on maintenance & or repairs & your boat will bite you back hard in your wallet. Like you tried to do with that gasket. I'm not beating up on you, gaskets are cheap. Engines aren't. Best of luck.