96' Force 120 Electrical Probem???

danny410

Cadet
Joined
Jun 29, 2008
Messages
7
I have a 1996 Force 120 thats came on my 96' 185 FS. I have never had any trouble out of the engine untill this past weekend. My son and I launched the boat, it cranked on the 1st try. My son backed off the trailer went out opened it up full throttle to warm it up as I went to park the trailer. When my son picked me up at the ramp we managed to go maybe 100 yards before the engine started losing power and sputtering. Initially I suspected bad gas or my fuel pump/ diaphram as in the past. I took it to my son's mechanic and he did a compression test, as well as checked the fuel pump, and carbs. He initially said it was hitting 2 & 4 at the same time and thought maybe it was the trigger or stator/power pack? Long story short my son's mechanic put used parts on it to see if he could isolate the problem. No luck. Any one have a clue as to what this could be? Ran like a top for maybe 10 minutes then left us dead in the water. Just turns over and pops? Thanks
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: 96' Force 120 Electrical Probem???

Why is it that the people who seem to have the most problems with these engines have taken them to boat mechanics? Am I missing something?

The firing order on that engine is 1,3,2,4. So the 2 and 4 triggers are 180 degrees apart. Also, if the Merc ignition is similar to Force, 2 and 4 are fired by a different CD box, and each CD box is charged by a different winding on the stator. SO: given these facts, it would be extremely difficult for the engine to fire 2 and 4 simultaneously, unless wires were crossed or shorted. Since the engine ran well before, crossed wires are not a consideration. However: The plug wires are connected top to bottom, 1234. If they are not connected this way, then the firing order is incorrect.

Unless used parts are specifically known good, consider them as defective and not a good test.

At this point, ---you said compression test was performed but did not give results--- you need to start from the coils and see if they have proper resistance and work back through the CD boxes, triggers, and stator. There is no quick way around it. See where you do have spark, and where you do not, then apply logic. Do not forget to check the complete fuel system from tank to carbs.
 

danny410

Cadet
Joined
Jun 29, 2008
Messages
7
Re: 96' Force 120 Electrical Probem???

Thanks,

I'm not sure on the compression test results. I was there when he was doing them but I do not know the numbers. All he just said it was good. He took the bowl off my two carbs and checked them when I was there. All looked ok. Also he checked the fuel line for break down inside, that too seemed ok. Next he checked the fuel pump and that was pumping fine. All of this was done with me standing there. All was ok with the fuel end of the engine. I have in the past have had two diaphrams put on this engine so I figured since it sat up a bit maybe it was that again. After he tested that he just told me the firing is or was off that leave it and he would swap parts off a used engine he had laying around. I left the boat and 2 days later he said he swapped my power pack and a few other parts and he could not get it to run. It was running fine then in 10 minutes time gradually lost power then died and never cranked again. I just ordered a Clymer manual on this model engine as I do tinker with VW engines. I just have no knowledge in outboards and don't know where to start? How can I test the stator? or trigger? or switch box? I need a little knowledge in what these parts do and a better understanding of them, that's why I ordered a manual. I apperciate your reply. Any info is useful. Just puzzling if it's getting plenty of fuel but not firing. No one had switched the plugs as when it died in the water it was and has been running just fine and not been worked on. I was there when my son's mechanic popped off the cowling and started with simple routine checks. I did notice he marked my flywheel with numbers so I hope now it isn't out of time? If you take off the flywheel will that throw the timing off? He said he worked on it for 2 days so now im not sure what he has done to my engine that was running like a top!
 

SwampThing

Petty Officer 2nd Class
Joined
Nov 6, 2006
Messages
117
Re: 96' Force 120 Electrical Probem???

Thanks,

It was running fine then in 10 minutes time gradually lost power then died and never cranked again.

Exactly what does "never cranked again" mean? No sound, no nothing?
Engine turns over and doesn't start?

Diagnosis must take a systematic approach. To put it nicely, your mechanic seems to be all over the place. Guessing with KNOWN GOOD PARTS should only be done to confirm one's suspicions AFTER PROPER diagnosis procedures fail to turn up the cause of the problem. But we're not even sure what the problem is yet.

So does it crank (turn over the engine but not fire)? If it doesn't turn over at all; start at the battery. Good battery? Charged? Someone put the cables on backwards? Then there's the starter relay/solenoid and the ign switch, kill switch / laynard, and neutral safety switch. Gear select in the right position?

Fire you Mechanic and lets go back to basics first.
We need 3 things here. Fuel, Compression, and SPARK. Okay, what's our dysfunction then? You said "no crank" so I'm not even going to worry about compression at this point.

If the engine is turning over and not starting; has anyone bothered to pull a plug wire, install a test plug (ground the outside of the plug) and check to see if the engine is indeed even getting spark? IF ti cranks and doesn't fire then this is the first thing I'm checking. If I've got spark, then I'm looking at fuel issues next.

Danny I'm sure you can fix this motor yourself with the help of the people on this board. Probably save yourself some money and frustration in the process.

In order to get you started in the right direction we know if you have a
"crank no start condition" OR a "no crank no start condition". Also does anything else on the boat have power to it? Lights, etc?
 

danny410

Cadet
Joined
Jun 29, 2008
Messages
7
Re: 96' Force 120 Electrical Probem???

We have a "crank no start condition" The engine just turns over but will not start. the battery is fully charged and fairly new, less than a year old. The mechanic tested fire to all the plugs when I was there with this electronic box he hooked up to the spark plus. He was puzzled too. He said no reason if it's getting gas and spark that it shouldn't start. He said maybe to him looked like it was either firing out of sequence or acting like it was firing all at the same time that it must be electrical and he would work on it. Needless to say he is stumped so now I have the boat back trying to figure out if it's one of the four black (power packs if that is what they are called? The box has a lead going to the spark plug) trigger? or stator? I'm just waiting on a Clymer manual to come int he mail because I'm not sure how to test those components as I'm not familiar with outboard motor repair. My boat does have nav. lights that run on the cranking battery as well as the fuel guage, trim guage, water pressure guage and tack. I have 2 other trolling batteries for the trolling motor and maybe the livewells and radio? I'd have to see what all accessories are run on the cranking battery and what ones are on the 2 trolling batteries. I had a Mercury 75 once with a bad stator so that made me think about that issue. I also am not sure what ignition system I have? (mercury thunderbolt) or the force ignition? How can I tell? My cowl says Force 120 by Mercury marine as it is a Nitro 185 sport. I was told it's basically a Mercury with a mix of Chrysler? Any help you can give me on testing will be a great help. I can also try to upload some pix under the cowling if that will help you look at what I'm looking at. Thanks!!
 
Top