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Joe, Marine Mechanic
Category: Boat
Satisfied Customers: 7251
Experience:  ASE, electronics, Marine mechanical and electronics, pwc, wiring, all around repair tech,
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12V92TTA keeps burning valves at 1750 hours. Could there be

Customer Question

12V92TTA keeps burning valves at 1750 hours. Could there be an issue with the supercharger drive preventing turbo,s from spooling up to full rpm?
Submitted: 1 year ago.
Category: Boat
Customer: replied 1 year ago.
This trawler has been operating for about 15 years without anything being changed in the drive line or net size. Everyone is looking at overload situation,but nothing has changed to cause one? I am suspicious of the supercharger holding the turbos from gaining full flow? Is there supposed to be a sprag clutch in the supercharger drive line to allow the turbo to blow through the super charger without restriction? If this clutch is faulty,or been removed will this cause an overheat in the exhaust valves? I am visiting the boat tomorrow and would like some advice on what to look for. Many experts have looked at this boat,and many tens of thousands have been spent on new heads ,turbos,overhaul kits etc.I believe something is being overlooked? Many thanks for your help.I can be contacted on mobile in New Zealand 00634272950900. Regards Colin
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Joe replied 1 year ago.


Thank you for allowing me to assist you, my name is Joe and I will be happy to assist you with your concern today.

I am just seeing if you still need assistance with this problem? The reason I ask is because I see that your question has not been answered sooner and I wanted to make sure if you still needed help.

In some cases a question may sit due to several different reasons. My objective that I wish is to make sure that if you still need help that I can at the very least reach out to you and attempt to help you.

At this time please feel free when you are ready to reply back to me and ask to continue working with me, another expert or if you no longer need help please just let me know exactly what you wish to do.


Customer: replied 1 year ago.
Hello Joe,I visited the boat on Saturday and found the issue was with an exhaust system that had been extended using too small a pipe,therefore increasing the back pressure to excessive level. I no longer require an answer to my question,thank you anyway. Regards ***** *****
Expert:  Joe replied 1 year ago.

Hi Colin,

That is very interesting, though to be honest nothing surprises me anymore as I have seen all sorts of craziness on boats. The too small of pipe would have only done that but would have also increase your exhaust temps egt's.

Glad you got that quickly figured out, have a good afternoon and please let me know if you need any further assistance at any time with any other questions.