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I have been working on this ski for the last several weeks. Here is the story...
I was taken to another shop after being purchased from a person that didn't use it very much since new to be checked out and get ready after being in storage.
They did some tests and determined it needed "new carbs" wich the customer had them put on. It ran great for two hours until the rear piston developed a hole in the top of it. At that time he called the original shop back and they said there was no warranty on the engine just the carbs they installed since it could be a lot of things that may cause the engine to blow.
He then called me and I agreed to look at it. I pulled the carbs off the ski and all the gaskets were there and the carb jets looked clean on the rear carb.
I could not tell if any of the carbs were replaced or not but they all looked very clean like the rest of the ski. There was no signs of water or debris in the carbs or the fuel filter. I recomended getting a SBT engine and testing the fuel system after it was installed. We procedded with that and the new engine came in and was instaled without any problems. The oil injection was also removed at this time.
I took it to the lake and did the first hour of the break in myself and did several plug readings and all looked and felt great. He came and picked it up the next day and over this past week end he finished the break-in and started his second tank of fuel using YamaLube 2W at 40:1. He got 1/4 the way threw that tank and it shut off at higher speeds. not knowing what to do they kept letting it cool down and rideing it until after several times it wouldn't run anymore.
I removed the engine today and found the rear piston has had severe detonation damage at the exhaust side of the piston and I will be sending it back in for repair.
I took the carb bowl cover, jets, and needle and seat out and eveything is clean and no water is present. 165 main jet is what is in it.
So my question is what else could be causeing the rear cylinder to keep having this problem.
Defective Carb? Ignition Problem? Ect? Any ideas?
I would like to get it corrected before the same thing happendsto the next engine.
I was taken to another shop after being purchased from a person that didn't use it very much since new to be checked out and get ready after being in storage.
They did some tests and determined it needed "new carbs" wich the customer had them put on. It ran great for two hours until the rear piston developed a hole in the top of it. At that time he called the original shop back and they said there was no warranty on the engine just the carbs they installed since it could be a lot of things that may cause the engine to blow.
He then called me and I agreed to look at it. I pulled the carbs off the ski and all the gaskets were there and the carb jets looked clean on the rear carb.
I could not tell if any of the carbs were replaced or not but they all looked very clean like the rest of the ski. There was no signs of water or debris in the carbs or the fuel filter. I recomended getting a SBT engine and testing the fuel system after it was installed. We procedded with that and the new engine came in and was instaled without any problems. The oil injection was also removed at this time.
I took it to the lake and did the first hour of the break in myself and did several plug readings and all looked and felt great. He came and picked it up the next day and over this past week end he finished the break-in and started his second tank of fuel using YamaLube 2W at 40:1. He got 1/4 the way threw that tank and it shut off at higher speeds. not knowing what to do they kept letting it cool down and rideing it until after several times it wouldn't run anymore.
I removed the engine today and found the rear piston has had severe detonation damage at the exhaust side of the piston and I will be sending it back in for repair.
I took the carb bowl cover, jets, and needle and seat out and eveything is clean and no water is present. 165 main jet is what is in it.
So my question is what else could be causeing the rear cylinder to keep having this problem.
Defective Carb? Ignition Problem? Ect? Any ideas?
I would like to get it corrected before the same thing happendsto the next engine.
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