# Mercury "tower of power" question



## shtbrd1 (Oct 2, 2007)

So Im looking at a boat that has a 1983 Mercury 90hp on it. Thing runs like a sewing maching; however when put in gear or at idle it dies....is this a serious problem, something fairly simple, or just comes with age of motor?

Opinions?

thanks


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## pappastratos (Oct 9, 2007)

Sounds like carbs need to be cleaned 1st.


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## TheCaptKen (Mar 14, 2011)

Or a fried cylinder


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## Tomslick66 (Mar 16, 2011)

Whenever looking at an unknown outboard check the compression!! Other problems can be worked out but if it has a blown cylinder you are signing up for a mandatory mechanic's course. (Ask how I know...)


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## Chapman5011 (Mar 7, 2013)

Carb problem would be the first thing to play with. 
Just needs a carb cleaning. Try that first before worrying if you have a blown cylinder or not. 
Youtube cam help you with the cleaning. You can probably go to autozone and use the loaner compression tester to aid with determining if you have a bad cylinder. 
Good luck


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## Papajuju (Apr 18, 2014)

First step to troubleshooting an outboard, compression check.

First step to buying a used boat, compression check.


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## The Maintenance Shoppe (Nov 5, 2007)

don't waste a damn bit of time doing anything else until you do a COMPRESSION TEST.:thumbup:


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## timeflies (Oct 3, 2007)

I'll post an explanation here, since the motor and boat in question is back on the market. This was a case of adjusting the idle on the hose and not in the water. I am sure the above experts can agree, that if you set the idle speed to 800rpm on the hose in your yard, it will be considerably lower once you put the boat in the water. I had adjusted the idle screw up, but did not tighten the nut to keep it set. Once on the water, it had backed it's way out and left me looking like a knuckle head. 

I came home and removed the cowling, and my mistake was staring me in the face in the form of a backed out idle adjustment screw. A simple fix and I was on my way.

Here is a video we shot yesterday of running the boat. This thing does 40mph plus, and as stated above, it "runs like a sewing machine." I never got the chance to put the boat back in with the buyer onboard. All advice above is good advice, and I would take any of these suggestions to the bank when buying a new boat. 

https://www.youtube.com/watch?v=3FCz79h64M4


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