Nissan 25 2-stroke trouble

[Shubobo72315]

This winter a friend borrowed my motor it is a 99 nissan 25 2-stroke and ran a tank of gas through it without mixing oil into it. He told me that it just quit running, and after it cooled off it runs ok now. It has lose a lot of power off the take off. It seems to take it forever now to get my boat on plane and also it has lost some of the top end. All I have done is cleaned my carb, and replaced sparkplugs. Is there anyone that can help me get it back to its old self?

 

[John_S]

Re: Nissan 25 2-stroke trouble

Well, I think you need better friends! :$

I'll tell you, it doesn't sound good to me. It takes awhile to run 6 gallons through that engine. Thats a long time without any oil. Especially running it at anything off idle. Running the engine under load, is a killer. There is most likely damage to cylinder walls, piston, and rings. Then ther the crank and connecting rod bearings. Start with a compression and leak-down test.

 

[TOHATSU GURU]

Re: Nissan 25 2-stroke trouble

And then tell your friend he owes you an engine. Even if the damage is limited to pistons and rings the existing service life of the engine was just cut by 90%.

 

[Shubobo72315]

Re: Nissan 25 2-stroke trouble

Thanks guys, I kinda figured that I would probably hear that. I don't know a lot about the blocks a boat motor, but are you able to take them to a machine shop and have the bored out, and replace them with bigger pistons?

 

[TOHATSU GURU]

Re: Nissan 25 2-stroke trouble

There are oversize pistons available, but your looking at $400.00 minimum for parts, $100 plus for boring and $400.00 labor to rebuild it....Even if the crank is good.

 

[Shubobo72315]

Re: Nissan 25 2-stroke trouble

If you put oversized pistons in it, would that increase the hp of the motor?

 

[TOHATSU GURU]

Re: Nissan 25 2-stroke trouble

In theory, yes...In reality, no.