95 4 cyl 2 stroke Mercury 115 no fire situation

Capt_Tom

Cadet
Joined
Mar 13, 2010
Messages
9
A couple of years ago, I purchased a Riviera Cruiser with a 2 stroke 1995 115 Hp 4 cyl Mercury outboard on it. THe engine appeared in good shape, had never been in salt water, and had 4 matching compression readings. It ran ok for a year, with the occaisional "shudder" of the transition of the 2 + 2 system. Then one day at about 2500 rpm, it was like someone shut it down. It dropped to an idle.. and stalled. I restarted it and it ran good for a moment and did the same thing. I babied it home. I had the boat looked at, and a week later I was sold a "switch box" (module). I ran the boat for about 20 minutes, and the problem re-occurred. (while the boat was in the shop, I purchased a Mercury service manual). I pulled the Emergency Kill switch and ignition stop wires off of the module and the problem corrected itself. I put one at a time back on, and the emergency kill switch wire was the culprit. (the boat doesn't even have a kill switch on it). Since that time, other than an occasional "stumble" in lower to mid rpm, it has run like a champ. That is the history...

Now, a year later, I plan to use the boat one weekend. I hook the battery charger to it. Several hours later, I return and fill the oil resevoir. I turned on the battery power switch, turned the key, and the engine immediately started. I turned it off and turned off the battery switch. I drove to the landing, turned on the battery switch turned the key... it spun but never fired a lick. No fire at any plug. I checked the inline fuse on the side of the motor, and checked for loose wires. Nothing. I took the ignition switch stop wire off of the switch box (module).. still no fire. I have disconnected the wiring harness connector from the engine, and ohmed the switch (in all positions) and wiring harness back to the engine. Everything that is supposed to have continuity does, and what doesn't... doesn't.

Does anyone have any recollection of no-fire history with this engine. Mod# 111541
 

multimech

Petty Officer 1st Class
Joined
Apr 26, 2012
Messages
386
Re: 95 4 cyl 2 stroke Mercury 115 no fire situation

If you have the kill switch disconnected properly. The engine turns, then you should have spark. If you don't. Check the stator outputs. Check the trigger outputs. I am betting it is your switchbox.
 

1nebel0

Chief Petty Officer
Joined
Nov 28, 2005
Messages
512
Re: 95 4 cyl 2 stroke Mercury 115 no fire situation

Disconnect the two yellow wires at the rectifier just to make sure that is not causing you problems...The blk/yellow wire on the switch box is your kill wire...disconnect it and if you have fire it is the switch...lastly to have no fire would most likely be the switch box...stator as two circuits...Low speed and High speed....Trigger has two magnets. Each magnet controls two cylinders...the chances of both going out are slim....there are tests for everything and that is what I would do..You need a digital meter with a DVA peak adapter to capture the voltage reading...good luck
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: 95 4 cyl 2 stroke Mercury 115 no fire situation

Download the free Ignition Troubleshooting Guide from the Support page of CDIElectronics

It will guide you thru every test necessary to positively determine the fault.
 

Capt_Tom

Cadet
Joined
Mar 13, 2010
Messages
9
Re: 95 4 cyl 2 stroke Mercury 115 no fire situation

Thanks for all of the info, guys!

I would have responded earlier, but I sometimes seem to be having trouble logging on. (And the other day I wrote a reply and exited without hitting "POST".. Duh!
 
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