1986 force 125hp outboard all of a sudden stopped running

mfkcbk

Recruit
Joined
Aug 26, 2017
Messages
2
My boat is a 1986 bayliner 19'. Earlier this week I was cruising down the river about 25mph when the engine just shut down after a couple of miles. I recently bought this boat and haven't had any trouble with it. I've run a few tanks of non ethanol gas this summer always with mercury 2 cycle oil and with stabilizer. This gas is only a couple of weeks old. After it stopped, I tried multiple times to restart. It would turn over and sometimes catch but then die. A couple of times there was a backfire. I took the cover off and did notice gas coming out of both carbs.
When I got it home I took both carbs off and cleaned them as best I could, but they didn't look gummed up or anything. I also checked the reed valves and they look tight.
The float needles looked fine. I just read that the float might not be set correctly and not pushing the needle up enough to shut off the gas so I'm gonna pull them off again and check that.
The thing that baffles me is why it shut down so suddenly and why gas is coming out of the carbs.
Any ideas on what I can try next? By the way, I'm no mechanic but am willing to try stuff as long as I don't mess it up worse than it already is.
 

Jiggz

Captain
Joined
Oct 23, 2009
Messages
3,909
Check compression on all cylinders and post results.

Check make sure there's sparks on all spark plugs. Use an inline spark tester which you can get at auto parts store for about $5. If there's spark on all plugs, next thing is to make sure there is fuel into the cylinder.

The best thing to do is to install a clear fuel filter between the fuel pump outlet and the carbs' inlet. This it has to be clear. This is mostly for troubleshooting rather than filtering. Prime the bulb and see if the clear fuel filter fills up. It should and if not then there is problem with the fuel delivery.

Test ran the motor on the driveway with muffs and cowl cover off. Get a 2nd person to do the starting (unless you have a remote starter) while watching the fuel filter. As you crank the engine, you should see fuel filling up the clear filter, if not check the fuel pump (diaphragm), fuel hoses for leaks, primer bulb, etc.
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,637
Check the flywheel key if is has shared.
Easiest way to do it is to put a screwdriver in top sparkplug hole then turn the flywheel by hand (pull all the other plugs too) in CW direction.
When the screwdriver reached all the way out as it will, the 0 mark (TDC) should line up with the 0 mark at timing plate.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,120
When you do the compression and spark tests, post the results.
Check for water in the fuel?
 

mfkcbk

Recruit
Joined
Aug 26, 2017
Messages
2
You guys are not going to believe this! I was just going to remove the carbs again for the third time, this time to check to make sure the float is pushing the needle high enough to shut off the gas. I happened to notice a green wire hanging in the breeze. I think it is from the CD module but not sure about that. Reconnected it to the terminal block where its connector was still screwed in and she started right up. Planning on taking her out later today and making sure all is well.
My next question, is a compression test still a good idea? I'm not sure what I'd do with those numbers unless they are a reference for a future problem.
My real concern now is that I may be way out of my league on the electronics of this motor.
Anyway, thanks for all the input.
Mike
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,120
Loose wire: one of the hardest things to diagnose?
Yes do a comp test anyway.
That will give you an idea on the health of your motor.
The reading should be within 5# of each other.

​But if it starts and runs then the comp is probably good.
 
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