91 Merc 200 power loss

[MACSOUT]

Hello everyone, I found one that has stumped me. The wife has a 21 Seacraft with a 1991 200 merc and up until last week, as you can imagine, the boat ran like a bat outa you know where. Anyway, the boat lost what seemed to be mid range and above rpm's and didn't idle too well. It acted like a coil breaking down. Tested the stator (ohm test) and it tested bad, installed a new one and a noticable change with the idle to the good but still has the mid range bog. All fuel lines have been replaced, coils ohm test good, fuel separator replaced, new plugs and plug wires. I'm still leaning towards a coil but believe a switch box might be the problem. Just guessing at this point I guess. Any suggestions appreciated

 

[MACSOUT]

Re: 91 Merc 200 power loss

By the way, I went through all three carbs, clean as a whistle. The boat doesn't sit much.<br />Thanks again

 

[Kenny Bush]

Re: 91 Merc 200 power loss

That is about the last thing to check...... The switchbox.

 

[Trophy23]

Re: 91 Merc 200 power loss

I had simalar problem with a 220 Mariner, 1989 2.4L model. Ended up following the guys instructions in this forum and changed out the Stator and switch boxes. The trigger checked good. I also had a rectifier that was bad. Now have 14 volts and runs good. I swapped switch boxes and motor wouldn't start, so figured one was bad. Guys here suggest changing both switch boxes if you are changing either. Mines an EFI, so don't know about the carbs. Good Luck.

 

[BRIAN03]

Re: 91 Merc 200 power loss

You need to check spark. If 3 hole are dead 1,3,5 or 2,4,6. you have a bad switch box. Its a common failure. When you replace a switch box you replace them in pairs. Most common iginition failure on that engine is a switch box.