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2000 40 hp 2 stroke concern

S

Sea2aeS

New member
2000 40hp yamaha 2 stroke PT&tilt. Inline 3 cylinder. The bottom sparkplug has become rusty on the outside of it. 2 sparkplugs above it are clean. swapped the middle plug with the bottom plug and after 2 trips out now, the bottom plug is developing some slight corrosion on it. There is no apparent area where water is entering the engine or exiting anywhere on the block. have noticed a few of the water cover bolts have slight bits of corrosion around the bolts as if they are seeping at the slightest possible amount.

the engine runs fine throughout all rpm ranges, idles fine, doesnt lack power, etc.... havent noticed any performance issues. inside of the plugs are clean, not showing any signs of internal leakage into the cylinders & appear correct in heat range.

-is this a major issue or a small problem thats going to get worse & cost me a ton of money?
im thinking there is the slightest of water leaks around the bottom cylinder with the water cover over the head & the head is fine, but the water cover & gasket may be bad & thats why it runs fine.

please help me with this. Is this a major issue or something that can be fixed or am i worrying myself over nothing? point me in the right direction of appropriate action to take, etc what can happen? what will most likely happen, etc. do i need to get this fixed asap?
 
Re: 40hp 2 stroke concern

I changed my plugs on my 50hp 2 stroke (2007) this week and noticed the same thing: rear plug had corrosion, others looked perfect. The rest of the engine looked fine. I wouldn't worry about it. Mine is like new otherwise and seems to always run great. There is no other corrosion anywhere else on the engine.
 
Re: 40hp 2 stroke concern

the water jacket over the cylinder head leaks at high rpm around the sparkplug on the bottom cylinder... ran the engine on the waterhose and couldnt find anything, soo................ decided to take her out with a friend. ran at 4000-5000rpm for 15 minutes. killed the throttle & came to a stop. removed the cowling to notice miniscule amounts of water seeping at the water jacket around the bottom spark plug from what im guessing is only enough pressure to force it at high speeds.

-can i just remove the water jacket over the head & replace the gasket or does the head come off with the water jacket on the same bolts?
-will this leak eventually grow & lead to engine failure if not repaired?
-wondering if i should just not worry about it & run it till she goes south & dies & replace with a larger 60-70hp 4 stroke
 
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