I know the compressoin's bad, what next?

[Clamboni]

Looked through a few pages of a search and didn't see anything helpful. I am buying a motor cheap, but it's sight unseen. I know it was run last year, but ran rough. The guy I'm buying it from said he had it compression tested and it wasn't even. Don't know how uneven. Not exactly sure of year, but He believes it's a 83 johnson 15. I haven't had an outboard apart before, but I'm sure I can tackle it myself. Not a real motorhead, but good with my hands and can follow instructions. What are the simplest things I can try out to see if it's something stupid causing the difference? I'm only spending $100 on the motor and am trying to keep the final price as close to that as possible. Just looking for suggestions to see if it's something simple. Like I said I haven't even seen the motor, so I probably won't be able to answer any wuestions for you.

 

[jfm1]

Re: I know the compressoin's bad, what next?

try to decarb it and run another comp.test 10-15% not bad depends on how low the numbers are?

 

[Mark42]

Re: I know the compressoin's bad, what next?

Could be head gasket. Or burned piston or broken ring(s). <br /><br />If you remove the head and nothing is broken, but there is some scoring, you can do the cheap fix: Put some motor oil on some emery paper 220 or so and sand the scored part smooth. Not the best fix, but it works. And if you want to keep costs down, it will do that too. Now somebody is going to yell at me for that suggestion....

 

[lastout]

Re: I know the compressoin's bad, what next?

I won't yell at ya' Mark, i just did the same thing to my 150 rude and it worked fine. rebuilt the aluminum cylinder wall with JB weld also so that the head gasket wouldn't blow for the third time. The moral to al this Clamboni is that there is more ways than one to CHEAPLY fix your problem. Only real problem is wether or not you trust your own work. Fixed does not always mean fixed Properly. Also, if it doesn't work out, there are probably more than $100 worth of parts on that motor. Good luck!

 

[Clamboni]

Re: I know the compressoin's bad, what next?

Yeah, that's why I figured I can't lose for $100. I was hoping it was a piston ring or something, I could just get a rebuild kit on ebay cheap. Good ideas so far, I was just kind of looking to try to figure out the little things to do before I tried any big things. Thanks for replies so far

 

[lastout]

Re: I know the compressoin's bad, what next?

without actually having the motor to run and test, its hard to figure if there are little or big things to work with. as always, you can always get your money back out of it. the investment is worth it if you want the motor. also, from experience, check your local shop for part prices before hitting the auctions. most times the prices are not that far off and there are no mistakes and easy returns if there are.

 

[JB]

Re: I know the compressoin's bad, what next?

Ahoy, Clamboni.<br /><br />Because of your short experience I suggest that you start with a Service Manual. It wont tell you everything, but it will provide terminology and context to make the best use of advice you get here.<br /><br />Get the model number to verify the year so you get the right manual.<br /><br />Good luck.