85hp 70s/80s Merc: crank, crank, crank, no start...

Z

zrock

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I recently bought an older Mercury outboard, 85hp. It has 4 cylinders and a two-piece top. The motor had been sitting outside for 3 years before I bought it. Anyway, the motor will crank just fine, however, it will not start. The bulb is firm, but it seems like it is not getting fuel...it will not putter or anything like that. Any suggestions?
 
T

turtles11756

Petty Officer 1st Class
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Dec 5, 2007
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260
Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

is there spark at the spark plugs ?
 
C

Chris1956

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Mar 25, 2004
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Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

Take a compression test, and then check for spark at each plug. Post results, and we can advise. It sould simply be that the carbs are all clooged up.
 
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zrock

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Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

The motor has compression and spark. Do I move on to cleaning/rebuilding the carbs?
 
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Chris1956

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Mar 25, 2004
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28,877
Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

The motor should fire if you spray 50::1 fuel mix into the carbs and then crank it. If it runs for a few seconds, it is likely your carbs are really clogged, and need your attention.

If it doesn't fire, you may have timing problems, and should perform the link and sync, actually you should do that anyway, after you clean the carbs.
 
R

ram50

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May 5, 2010
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Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

I just resently got my 1975 merc outboard running and it had set for 4+ years outside. I however could get it to spit and sputter. I ran some sea foam through it and rebuilt the fuel pump ( just a bunch of gaskets and a new diaphragm) took all of 10 mins to rebuild it. If you are not getting fuel I would do like the others are saying Carbs and I would check the fuel pump
 
Z

zrock

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Re: 85hp 70s/80s Merc: crank, crank, crank, no start...

Thank you. Seems like I have my weekend all set! I will post any updates.
 
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