Manifold Bolts keep coming loose

[Schindog]

I have seen a few post that have had the same issue with the Manifold screws keep coming loose. Has anyone found a way to fix this so it does not keep happening? All Suggestions are welcome.
Thank you

 

[mikidymac]

Yes, replace the rubber bushings and metal sleeves on the pipe mounts. That is typically the cause. Loctite on the bolts and gaskets go on dry.

 

[Schindog]

Thank you! I'll post the outcome when complete.

 

[Schindog]

I bought a used manifold in much better condition where bolts go. I took jet ski to lake and it still would only go half speed. And it dies when idling and I could not get it to start again. Took it home and it only started occasionally. Now it will not start. And I hear that THUMP sound only once in the times it does not start. I’m thinking that’s the starter relay but I don’t think that’s the only problem because why is it only going half speed or less. About 20mph. I had carburetor rebuilt. This is making me go crazy! Please help if you can. Thank you.

 

[etemplet]

I went through the same problem on a 1996 GTI and spent a great deal of time with it. I replaced the exhaust pipe rubber mount bushings with new, and changed out the manifold as you did. I even stoned the manifold and exhaust flange surfaces to insure they were flat. I switched from a graphite gasket to the dry material to eliminate slippage. I got the engine alignment dang near perfect and made sure all the mount bolts were good and tight. I cleaned the individual shims under the engine mounts to insure good solid contact.. I did a top end on the ski as well. I had suspicions that perhaps the crank was out of balace but it ran great.

When your manifold gets loose cooling water can get into the engine. that in turn can damage the rotary valve. The valve will bow away from the pressure. Once the valve becomes deformed enough the ski will be very difficult to start. In your case I'd start by removiing the cover of the rotary valve and having a look. After going over and through everything much like you just did I'd make checking and tightening the bolts a routine maintenance item.

The history of the ski was this --- 1996 GTI engine compartment was filled with water due to the owner leaving out the drain plugs. He then tried to start the ski without pulling the spark plugs which sheared the drive off the starter. Since that time the ski had issues with the bolts constantly loosening and the owner never checked them.

Long story but you basically do what you can with what you have. Good Luck.