1997 75hp Force won't start.

[fish4rob]

You all helped me with a fuel flow issue before and I thank you for it. After I changed hoses and filter, engine got fuel but ran rough. Adjusted carbs and did fine. Today,I was running at WOT when I pulled back throttle the engine died as if fuel starved. However, now it will not start back up. It does not seem to be getting any spark. It will crank over and over, but no spark. My buddy checked compression for me and it is fine, but he knows nothing about electrical. Any Suggestions?

 

[fish4rob]

Re: 1997 75hp Force won't start.

Just messed with it some more. It is getting spark. Won't start. Seems as if kill switch is engaged, but wouldn't that not allow for spark? Is this a possibility and can I bypass it to check it? What are the other possibilities?

 

[pnwboat]

Re: 1997 75hp Force won't start.

What were the compression readings?

Yes if the Kill switch was engaged, then you would have no spark. To disable the kill circuit, unplug the black wires with yellow stripe that runs from each of the Coil/CD units. They're all tied together and connected to one "bullet" connector in the wiring harness.

Seems like you were having some fuel delivery problems. Maybe you need to check that out first. Does the primer bulb get firm after squeezing 4 or 5 times?

You said you "adjusted" the carbs to get it to run better. What exactly did you adjust on the carbs? Did you adjust the idle mixture screw? If so, how many turns out from lightly seated are they?

 

[fish4rob]

Re: 1997 75hp Force won't start.

My buddy told me the compression was 120 on each cylinder. I adjusted the idle mixture screw. I'm not sure from tight, but I just tightened it a half turn from where it was. I made sure that the carb was getting gas by putting some in there. Still no start. I checked the plugs by taking them out, putting the wire on and holding on boat body while trying to start. Got a blue spark each time. Not really sure of the problem. When I pump the bulb it does get full after a few squeezes. Can you think of any reason that it may have started doing this after I throttled back?

 

[pnwboat]

Re: 1997 75hp Force won't start.

Next thing to check are the reed valves. They sit underneath the carburetor adapters on the block. You have to remove the carbs first. Then remove the carb adapters. I suspect that you may have broken a reed valve. The reed valves act as a one-way valve for the air/fuel mixture into the crankcase and controls the flow into the combustion chamber. The faster you go, the more stress there is on the reed valves. The later model motors have more of a tendency to break a reed valve petal than the older motors. The fact that the motor was running rough at first may have been due to a reed valve starting to fail. When you went WOT, it may have done it in. Hey...at least it sounds like a good theory. Only way to tell for sure is to take it apart and inspect.

How many carburetor(s) do you have on your motor?

Reed valve assy. is item 8 in the diag. below.

http://www.boats.net/parts/search/Merc2/Force/75%20H.P.%20%281997%29/0E203000%20THRU%200E287999/FUEL%20INTAKE%20SYSTEM/parts.html

 

[fish4rob]

Re: 1997 75hp Force won't start.

Thanks for the reply. I had to replace reed valves a couple of years ago. When they went out, the boat would start fine, but it would die immediately as you tried to throttle up. i didn't fix it myself, but withthat diagram I may take a crack at it.

 

[fish4rob]

Re: 1997 75hp Force won't start.

Alright, been busy but had a little time. Took the boat to my buddy and we rebuilt the carbs. Tried everything and still would not start. We checked for spark and there was none this time. Great!!! talked to the mechanic he worked for and he said that I needed to have stator and ignition system checked. I decided I would leave it alone until spring. Changed my mind afterthinking about it and decided that there had to be a short in the system. Disconnected the black and yellow wire at engine and instant spark!!! Started right up. However, I could not get the engine to stop with the key. I had to finally pull the plug wires to get it to shut off. What shoould I do to fix the short in the line and can I leave the kill switch disengaged and use the boat normally? Sorry for long post.

 

[surfsalterpath]

.....so your issue was kill switch related~
my 75hp 1996 force died at just above idle heading out on the water for the day. would not restart. it would turn over awesome but no start. weird.

 

[jerryjerry05]

You need to start a post of your own.
​The Mods get upset when you open posts that are years old.

​That could be?? flywheel key sheared, water in the fuel?

​Do a compression, spark test.
​Then check the timing.