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I did a compression test on a motor I'm planning on buying, a 2006 Mercury 50hp 2stroke oil injected. I got 120PSI on all 3 cyl.

I'm not a big expert on motors so, I'm wondering what that means? 

Still good? Enough life left for a few summers? Needs rebuild soon?

Thanks in advance for advice!

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As mentioned above I too would be looking at the difference between cylinders as my guide. That's because there's a hundred different ways to measure compression (only one right way), so the difference between them is key as long as you do it the same way each time.

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my limited research when looking for my own used outboard recently said that 110 is solid compression so 120 should be  great. 

 

As mentioned you dont want variation because in my very limited knowledge, different compression means that your cylinders would be working at totally different air to fuel ratios and be combusting at different rates, Jeez i think on a non fuel injected engine this may even throw off timing (i might be talking out of my you know what?? which in my understanding can cause certain cylinders to start taking additional load and I imagine create even larger variances until your engine totally goes.

Edited by AKRISONER

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You have excellent compression. I would also look for a strong stream from the cooling overflow also known as the pisser and the overflow water should be cold.

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I would think that's a pretty fair price.. maybe even on the low side of things. Outboards aint cheap. 

I have a 2009 50hp and love it.. great motor.

Edited by boombap

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1 minute ago, boombap said:

I would think that's a pretty fair price.. maybe even on the low side of things. Outboards aint cheap. 

I have a 2009 50hp and love it.. great motor.

I know. Was hoping for a 4st but couldn't find anything under $4000

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a 50 for 2,500...depending on how much it got used...id say thats a solid deal man. Outboards aint cheap at all, and a 50 will get a lot of boats around really well.

Im slightly wary of mid 2000's 2 strokes from when the new emmissions standards took over requiring direct injection rather than carbureted 2 strokes of the late 90's...im sure it will be fine though.

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I think this is a traditional two stroke.  They were made until at least 2008.

 

 

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