1990 Mercury 40 Classic Switch box

flash1977

Cadet
Joined
Mar 13, 2009
Messages
23
I bought a 90 Merc 40 Classic for my boat and carried it out last month to test run it. The switch box was bad, only getting fire on two cylinders. The boat hit a top speed of 5.2 mph!

The question I have is this, I found a switch box off a mid 70's 85hp. The switch box was put on the 85 a couple years ago but it doesn't look quite like the one I have (studs are on side instead of front.) An outboard guy here tells me to that most Merc 4 cylinders are pretty much the same as far as the electronics go, so....Will this switchbox work on my outboard or no?

I am trying to find a cheaper used switch box because I am not working presently and don't have a lot to play with but would like to get my boat operational so that I can catch a few fish.

Thanks for the help!
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1990 Mercury 40 Classic Switch box

Why do you think it's the switchbox? 2 cylinders not firing could also be the trigger.

Have you checked the trigger outputs with a DVA meter?

As far as the mid 70s 85hp switchbox goes... Be very careful. Merc changed from distributor ignition to ADI on the 85s in the mid 70s. If the switchbox is bigger and has 4 terminals down one side and 3 down the other.... it's NOT for your engine. Post a photo and we can tell you... (or the link to the site if you've found it on-line)

Chris......
 

flash1977

Cadet
Joined
Mar 13, 2009
Messages
23
Re: 1990 Mercury 40 Classic Switch box

I took the boat to a friend's who is an avid outboard guy. He checked a couple things and told me it was the switchbox.

As far as the switchboxes go, the one that you described with 4 posts on one side and 3 on the other is the exact one that I found on ebay. I was trying to save a buck or two by getting it but I will not get it. Thanks, that is what I needed to know.

Scott
 

flash1977

Cadet
Joined
Mar 13, 2009
Messages
23
Re: 1990 Mercury 40 Classic Switch box

Switch box fixed the problem....Thanks again for the help
 

zorak

Petty Officer 2nd Class
Joined
May 19, 2009
Messages
164
Re: 1990 Mercury 40 Classic Switch box

Guess it helps to be lucky sometimes.
 
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