1984 90HP Merc-Won't fire

nightstalker

Chief Petty Officer
Joined
Dec 10, 2003
Messages
570
A buddy's 1984 90 HP Merc was running fine and then just died last time out. Turns over but won't start. What do I check first? :confused: <br />Stalker
 

Clams Canino

Commander
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Jan 10, 2004
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2,179
Re: 1984 90HP Merc-Won't fire

Get the manual and ohm out the stator, then the trigger, then the switchboxes get suspected. Disconeect the blk/wht bias wire between the 2 boxes to isolate them for tests.<br /><br />-W
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 1984 90HP Merc-Won't fire

First, Nightstalker, go to the Engine FAQs section, "Outboard wont start".<br /><br />Report what you find. It is likely that Clams has you on the right track, but I would like to know that you don't have a fuel problem.
 

Clams Canino

Commander
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Jan 10, 2004
Messages
2,179
Re: 1984 90HP Merc-Won't fire

Ya, I was "assuming" it's getting fuel and won't spark. JB's right.<br /><br />-W
 

nightstalker

Chief Petty Officer
Joined
Dec 10, 2003
Messages
570
Re: 1984 90HP Merc-Won't fire

I'll check it out Sat. I'll let you know what we find. <br />Stalker
 

nightstalker

Chief Petty Officer
Joined
Dec 10, 2003
Messages
570
Re: 1984 90HP Merc-Won't fire

Checked it out Sat. No spark but it's getting fuel. Switchplate OK, rectifier OK, some other little guez OK. We gave up and called the local Merc. dealer. He's supposed to look at it this week.<br />Stalker
 

nightstalker

Chief Petty Officer
Joined
Dec 10, 2003
Messages
570
Re: 1984 90HP Merc-Won't fire

Guy from marina comes, checks engine, says it's the starting switch. Puts new switch in and she fires right up. He started engine from beneath the shroud first (I couldn't see what he hooked up). I guess the starting switch not only controls the starter but also the spark to the plugs. I would have never thought of checking that out (I didn't see anything in the shop manual about checking the starter switch). Cost my buddy $200 for the switch and two hours of "road" labor.><br />Stalker
 
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