I have a 2001 150 hp 2 stroke Yamaha Salt Water Series engine. I had a friend change out the batteries and asked him to check the engine as well. He said he found some rust in one spark plug and some water in another. I did not winterize the engine and did not put any recent fuel stablizer in the fuel until after the friend told me about his findings. In truth I do not run the negine enough, allowing my kids to do so when they please. It has not been run much since last year last summer when my girls and frineds took it out on Lake Pontchartrain. My friend did not have a way to check the pressure on the engine or the experience but suggested that I not take the boat for a long distance and stay near the shore. Any ideas as to what could be the problem or who to fix it.
Make (of engine): Yamaha
Model (of engine): 2 stroke Saltwater Series
Hi my name isXXXXX will assist you.
The only way water can get into the cylinders on these engines is a blown head gasket or a hole in the cylinder wall. Now since this is a new engine the head gasket would be the only real place as it is not old enough to have a hole in the cylinder unless it threw a rod. I would check the compression to see what kind of readings you get. The other thought is do you really have water in the cylinder or is this just a rusty spark plug. So the first thing to do is the compression test. The compression should be 100+ psi with no more than 15% difference between cylinders. If one cylinder comes up low remove the cylinder head and inspect. If the compression is good run the boat see how it performs. If performance is good use the boat if performance is down we need to go further.
If it is a blown head what cost should I expect to have it repaired?
Head gasket around $ 50.00 and 2 hours labor at the shop rate in your area. The head should be checked to see that it is not warped.
Hopefully it is the gasket. The friend said the engine runs pretty well without allot of vibration or noise. I have not run it as I did not want further damage.
I appreciate your help. It is nice to know that you are around to answer my questions and that the problem may not be catastrophic. Since I am not an mechanic, I will get someone who is to check the engine.
35 yrs. experience. I/O, Outboard & Inboard, Complete engine repairs.Certified Technician