1987 mercury 90hp power trouble

C

cavell491

Cadet
Joined
Jul 29, 2007
Messages
6
I have a1987 90hp mercury it was running fine until a week ago when suddenlly I lost power.When I run it starts and idle fine and it will rev up to 2500 rpms and then it won't go any higher.Don't know if it is related but I been finding a black oily mess coming out from where my prop and my lower unit connect something I didn't notice before.I been reading the forum and it seems it could be that my floats are stuck.I try to go to a shop but they are two weeks out and salmon is running hard on my neck of the woods.If somebody could give me detail information on how to fix my floats it will be greatelly apreciated.If there is any other suggestion on what it could be I will like to hear it to.Thanks
 
Grant Brown

Grant Brown

Petty Officer 1st Class
Joined
Mar 13, 2004
Messages
390
Re: 1987 mercury 90hp power trouble

Sounds just like my 1987 merc 70 3 cyl. Would run fine at idle but not rev out. Took forever to get on plane. After awhile it would "clear up" and run fine for the rest of the day.
I went through the carbs twice, linkage, tested everything but it turned out to be the switchbox (seems to be a very common problem on these motors). I replaced mine with an aftermarket one from an ebay dealer for $120 - 3 day shipping included. Ebay auction number 280110476714. Beats the heck out of the $425 I was being quoted by a dealer.
The boat hasn't ran this good in many years...
Go through the carbs and make sure but I'd keep the switchbox in mind.

Grant in Vancouver
 
C

cavell491

Cadet
Joined
Jul 29, 2007
Messages
6
Re: 1987 mercury 90hp power trouble

Thank you for the quick response. I took the boat to the water today after tightening all cables on the switchboard (wishful thinking)and it's even worst it won't even idle and is smoking like crazy.
 
S

sinbad jr

Cadet
Joined
Sep 6, 2007
Messages
15
Re: 1987 mercury 90hp power trouble

me 2 same thing ended up being the switch boxes..........
 
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