35 TE STB Side Engine Mount Galvanic Corrosion Issue

[dmorlo52]

Chris

Yes it is an RHC7W Turbo. It only sat over the winter but water did get in over the years due to exhaust elbow position from the factory. Turbo housing had some corrosion but not as bad as elbow. Obvious water was getting in due to back flow. Turbine rotor looked ok. The waste gate linkage looks ok but could not manually move it. Not sure if actuator is working. What makes actuator work to lift the linkage? Vacuum or just mechanical. (Novice here) I can remove it and see if I can free it up and inspect all the surfaces as well. Is there a way to test the actuator?

David

[rcwhite]

The actuator is spring loaded and opens the gate in response to manifold (boost) pressure. Low pressure
air can be used to confirm it's operation. It should "open" as the pressure increases and then
return (close) when pressure is released. If there is any question on the gate being stuck, you would
need to disconnect the linkage for testing. With the actuator disconnected, you should be able
to easily verify if gate moves freely or not.

[Halcyon]

Pretty boat. it look like the first mate is drinking a beer though...

To clarify the dorade box work can be done from the outside.

When you get a chance would you post a picture of the opening part of your tackle station? Mine doesn't open.

[dmorlo52]

We do not have a tackle station. On the port side is combination sink, empty compartment and freezer. I did take a picture of the latches for you.. The freezer lid does not have a handle you have to lift it with your finger tips. Nice to have freezer and the icemaker on STBD side. Will send pics next. Yah, we drink beer until dinner time then wine after that.

[dmorlo52]

Halcyon,

Here are the photos of the cabinet.

[dmorlo52]

Chris,

I have a suspicion the waste gate is stuck closed which is why I can only get 2800 rpm. I plan on taking the turbo off this Sunday unless weather is great. I will run her at 2600 rpm until I can remove and inspect turbo and see if waste gate housing is salvageable and it can be freed up. Will also clean and inspect rotor and will test actuator.

Hopefully, this will go right and I DO NOT HAVE TO BUY A TURBO!

Thanks to all that have posted on my issues and I will let you know what I find out.

David

[rcwhite]

I may not have explained this well. The waste gate opens to stop the turbo from developing too much boost so if it were stuck closed it would overboost the engine and result in higher output/rpm.
A stuck open gate wouldn't allow the turbo to build up full boost and the engine would suffer from poor performance/low rpm.

The spring in the actuator can be stiff so if you haven't disconnected it for testing it may be difficult to determine if the shaft is stuck.

There are other simple things that can contribute to low top end, leaking hoses or fuel delivery restrictions for example that are worth a look as well. Did someone tell you the gate was stuck or have you seen it? Both engines or just one?

Hope this helps clarify.

[dmorlo52]

Chris,

Mechanic here in marina disconnected the actuator arm from waste gate lever and he could not move it in either direction. After what you described above it has to be stuck open as I only get 2800 rpm on 3300 motor. I can disconnect hose on turbo end and stream air pressure into actuator to see if it moves. How much pressure should it take? No fuel restriction, no black smoke just as normal. New fuel filters, no restrictions. Put vacuum gage on racor today but have not fired it up. Putting on boost gage this week and maybe exhaust gas temp gage as well.

[rcwhite]

I don't have the detailed specs for this but it probably should open somewhere around 30. Sounds
like the gate is stuck if it was checked with the actuator disconnected. With any luck you will be able to
free it up with the proper application of heat and penetrating oil and the turbo is ok.

[dmorlo52]

Definitely hoping turbo is ok. Let you know what I find out.

Thanks for all your input. Where is Southport?

David

[dmorlo52]

Well guys, turbo is done! The waste gate was corroded fully shut with lots of corrosion products inside the housing. Can't free it up and casting is shot so I would not put it back in. Installed new turbo today and will test run tomorrow and if engine rpm is not restored it must be something else like fuel flow. Like I said no black smoke. Installed boost gage and oil pressure gage as well as vacuum gage on racor so this should help with further diagnosis. I have pictures of turbo housing (the section that the waste gate is in) and I will post them later. Still trying to figure out the wet stringer. Seams to be more evident with full load of fuel and 80 gals of water.

[dmorlo52]

Here are some pics of the corroded turbo. Caused by Albin's poor exhaust design!

David

[Bristol32]

What was the corrosion from? Was it a result of that wet stringer?