My deal on a complete package turns out not so good?

Advise from you veteran boaters...
First of all, I'm still excited about owning my first boat. But it came with a price. The craigslist add said motor runs good just needs a carb re-built. Not so fast. Compression on the cylinders are more than 10% apart which is not good. That's what my local boat mechanic told me anyway. It could last 30 days or it might last 10 years (his words).
I'm leaning towards run it until it really starts running bad then spend the money for a overhaul (which will have to come after summer). Second, does anyone know a ball park figure on how much a ring job would cost on 25hp Mariner 1998?

P.S. The compression was 125 and 105. Which is closer to 20% instead of the recommended 10% allowance.

Thanks again for your help and info!

Sharpie

My guess would be $800-900 from a mechanic depending on what else he finds or breaks while in there. I am not sure about Mercs but I know OMC over the years has backed off to a 15%-20% difference in cylinder compression. Have you tried running some seafoam through it yet to see if you have a stuck ring? Sometimes seafoam will breaks things loose and increase your compression readings.

Thanks Johny25. I will get him to do that. I guess I will take my chances until winter. I know this motor has been sitting for about three years so the seafoam sounds like a winner for the time being. Because $800-$900 is definitely out of the question right now.

I have heard of people using Deep Creep by seafoam also. Here is a link to it : )
https://www.seafoamsales.com/deep-creep.html

Johny25 said:

I have heard of people using Deep Creep by seafoam also. Here is a link to it : )
https://www.seafoamsales.com/deep-creep.html

Click to expand...

Good stuff.. I use it for decarb, may loosen up stuck rings if you do it rite and get your comp with in range.

If you can do the compression check yourself, remove the sparkplugs and squirt some oil down the cylinders to see if it improves the readings, especially in the questionable cylinder. If it does, then yes, you probably need some work done.

Don't feel bad, used stuff almost always comes with a price to pay.