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Posts: 192
| Have a 94 Johnson 60 got the boat out of storage tonight fired up great and ran for 10 mins to move some fuel from sitting. Pushed her back in the barn and check the compression a hour later 125 top, 125 middle 110-115 bottom. Should I consider rebuilding it or run some ring free and test later this season. The motor runs great and reves hard on the water no issues on power. I'm kind of anal on this stuff I'd rebuild it tonight if I had a kit sitting here lol I just keep my stuff in tip top shape. Am i worrying about nothing ? |
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Posts: 1120
Location: West Chester, OH | You are worrying about nothing! 
Lacking a manual, I'll guess that 125 is excellent compression on that motor & your low cylinder is still within 10%. You'd risk all the other stuff that could go wrong during a rebuild to correct that?  |
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Posts: 192
| Manual says 15 psi variance is out of spec my gauge jumps from 100-125 and it was a 1/4 of the way between 100-125. Gauge is just a cheap 30$ ati brand. I know the bottom cylinder also supplys vacuum to the pump. |
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Posts: 271
Location: davis,IL | I'm about as anal as you about having absolute reliability from my boat/motor. If it were my boat.... I would drain my fuel.. put in 8 to 10 gallons of 91 octane ethanol free gas and ring free (A little heavier dose) and run synthetic oil. Take it out for the day and do a new motor break in routine... idle...w.o.t.... and everything in between, not running at a steady rpm for any extended periods... mix it up. After burning that tank out, I would go to maybe 5 to 8 gallons of the 91 again using just your normal mix of additives (seafoam) and synthetic oil, run the way you normally run it. Now... recheck your numbers and see what happens...I am assuming this a 2 stroke motor, I have not run a 2 stroke in 15 years, but, when I did, synthetic 2 stroke oil ran better than regular 2 stroke oil. The motor smoked like a beast the first tank or 2 after switching up, but ran noticeably better once it settled in. The heavy load of ring free should break free any carbon hanging up the rings. Its cheaper than a rebuild and may be the "cure" you seek.
Edited by muskydope 3/19/2016 12:05 AM
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Posts: 192
| I run 91 ethanol free I'm going to decarbon with a heavy dose in the tank and see what happens. Even if the number don't improve I'm not worried too much a rebuild kit is 500$ sounds like a good winter project if need be. I have rebuilt atvs and other motors a 2 stroke is about as easy as it gets. |
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Posts: 1088
Location: Hayward, WI | I would give the motor a cleaning with Powertune and then do a leak down test. Much more accurate. Powertune is sprayed into the carbs when motor is running. You let it sit and then run it to flush the crud out. If there is a ring hung up it will help free it up , along with getting rid of any carbon deposits. If really anal, a borescope would show you if there is any scoring to the cylinder. |
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Posts: 192
| I took the carbs off and Gave them a cleaning and set up properly. Got that done and stared it up and tuned the low speed set up and ran smooth, let get to running temp and rechecked with all the spark plugs removed this time and the numbers were all 115 across all 3 cylinders I don't think I have a problem it runs great. I don't know why I was getting different readings the other day? Cold motor maybe it needed to run a bit more and rev up to clean out carbon? |
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Posts: 668
Location: Wisconsin | Well that's good news! I would guess the cold motor, but I guess it's all good now. |
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Posts: 208
Location: Sun Prairie, WI | If it runs and runs good whats the problem? I wouldn't worry about it. Keep a good water pump and thermostat in the motor. Run good gas and good oil. Your just gonna open a can of worms if you rebuild it. Leave it alone. Just my 2 pennies worth. |
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Mechanics advice wanted