Force 1987 125 HP doesn't start sometimes

[sidenberg]

Went fishing. Engine started up right away at the start and ran perfectly. AFter running about 45 minutes I shut off the motor to fish. After sitting about a half hour tried to start but no go. Motor turns over but found no spark. AFter sitting for about 20 minutes engine started up and ran fine. Went to another frishing spot. After sitting for awhile engine would not start. Started into port using 7 HP auxillary motor. AFter about 30 minutes Force started up again. Got into port and shut off motor. Waited 1 minute and motor started up fine several times. What would be the most likely cause of this problem?

 

[foodfisher]

Re: Force 1987 125 HP doesn't start sometimes

Because it's a warm/hot engine when the prob. occurs, I'd say a short caused by expanding metal is to blame. Bare wire? There's always the bad ground=mysterious elec. problem connection.

 

[pnwboat]

Re: Force 1987 125 HP doesn't start sometimes

If you have a Kill Switch, make sure it's working properly. An intermittent kill switch could cause the problem you describe. With the lanyard attached, the kill switch should read "open" with an Ohm meter. When you pull the lanyard off, it should read .1 to .3 ohms or basically a dead short. This is how the kill switch works. It shorts the ignition signal to the CD packs to ground, killing the ignition.

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes

Yes, the kill switch and the expanding metal concepts sound logical, however when the motor runs it never dies. Wouldnt an intermitten kill switch problem or expanding metal causing a short, cause the motor to die while it is running? Hmmmm.....

 

[patrickj]

Re: Force 1987 125 HP doesn't start sometimes

id check fuel pump or fuel lines, and make sure your gas tank vent isnt clogged.

 

[foodfisher]

Re: Force 1987 125 HP doesn't start sometimes

When you throttle down you change the positions of all the above to maybe the short or kill spot.

 

[Jiggz]

Re: Force 1987 125 HP doesn't start sometimes

Partially accurate but not entirely. When an engine is running so is the cooling fluid. When shut down after a long run, the cooling stops abruptly and engine heat accumulates that can raise the temperature higher than when the engine is running but not hot enough to trigger the hi-temp alarm. It's like residual heat which never got cooled. Instead the heat is dissipated through the external surfaces of the engine enclosed by the cowling which can affect wirings and other stuff in the cowling. So I would still focus my troubleshooting on a grounding wire or electrical. This would have to be located inside the cowling where it's affected by the heat. And you mentioned there was no spark, so that alone tells you the problem is electrical.

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes

Very good. Thank you all. I will post my results when I locate the cause.

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes ......STILL

Re: Force 1987 125 HP doesn't start sometimes ......STILL

Dang, still cant find the problem here. I have gone through all the wiring and found nothing. Boat has sat in the driveway for a month. It started up today on the trailer right away first crank. I let it run for about 15 minutes then shut it off. Waited about 15 minutes then tried to start up again but no go. Carbs are getting fuel but no spark. What could be the cause? Bad circuit breaker?, Rectifier? What?

 

[Jiggz]

Re: Force 1987 125 HP doesn't start sometimes ......STILL

Re: Force 1987 125 HP doesn't start sometimes ......STILL

Glad to hear back from you. Can you try running it again and then only for about 2~3 minutes shut it off and then wait for about 2~3 minutes and start again. If it starts, let it run for about 5~8 minutes and then turn it off and wait for another 5 minutes and then start again. If it starts without a problem continue to run for 10~12 minutes. Turn it off wait for about 10 minutes and turn start again. if it start again continue raising the running time and shut time until it won't start no more. Then feel with your hand how hot the coils and packs get. It could be that the packs are getting ready to fail and when they get hot opens a circuit and will not work until it cools down. If the engine won't start even before it gets really warm, then the problem is something more than just something getting warm, it could be a loose connection that gets disconnected with vibration. Don't forget to check the shutdown switch wires which are not supposed to be grounded until you press the switch or turn off the ignition switch to off position.

 

[RRitt]

Re: Force 1987 125 HP doesn't start sometimes ......STILL

Re: Force 1987 125 HP doesn't start sometimes ......STILL

I'd check carbs, fuel filters, fuel pump, etc. My forces would get all finicky about starting from the 2stroke oil residue that builds up in carbs. After a good clean up of the fuel system they would start and run like new.

 

[Frank Acampora]

Re: Force 1987 125 HP doesn't start sometimes

Try it again and this time when it doesn't start, change the sparkplugs with new ones of a different brand. So, If you are currently using Champion, then switch with NGK or Autolite.

The ignition is self energising and almost anything other than sparkplugs that would cause a no spark condition at start would also stall the engine while running.

However, these ignitions produce their minimum voltage at cranking speed, just when the demand from plugs for voltage is greatest. Malfunctioning or fouled plugs WILL RUN with these ignition systems while refusing to start.

Additionally, because of compression, a hot engine will crank a bit slower than a cold engine, producing less ignition voltage, sometimes below the threshold needed to start. These engines MUST crank at at least 350-500 RPM in order for the ignition to spark (I forget the exact RPM they need). Therefore, check the condition of the starter motor to see if it is cranking the engine at sufficient speed while the engine or the starter is hot.

Lastly, if all else fails, check the flywheel magnets to be certain they have not lost some strength.

 

[Jiggz]

Re: Force 1987 125 HP doesn't start sometimes

Frank put up a good point since the plugs are the first to suffer or get affected by heat since they're literally imbedded in the block. However, with four plugs you would think at least the engine will "cough" if at least half of the plugs are bad when hot. Unless, coincidentally that all plugs happened to be faulty at the same time which is hard to believe but not impossible. So the question, does the engine "coughs" on those times when it wouldn't start. If it does, then changing the plugs could be your solution.

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes

Here's the thing. When it doesn't start I checked all plugs and none are getting spark. Today I can not get it to not start. I have run it for 15 to 20 min and shut down for 5 min again for 20 min and again for 1 hour. It starts right up every time. WTF!

 

[Jiggz]

Re: Force 1987 125 HP doesn't start sometimes

So what have you done since the last time it didn't want to start? I mean even the simplest things you did which could have mitigate the problem.

 

[moparman]

Re: Force 1987 125 HP doesn't start sometimes

you could possibly have a cd unit and/or coil that gets heat soaked so that after running and shutting it off and letting it sit for 15-30 min it's [cdi unit,coil,most likely trigger ]is dead. What ever it is ,it's killing all spark and not just 1 or 2 cylinders, that's why I said trigger more so than all of the coils or cdi units going bad at one time. Also might want to check the magnet in the flywheel to see if it's starting to come loose, and rubbing the wires .After cooling off it starts working again, you most likely will need your v-o-meter to check it when it's in the no start mode, just my 2cents worth. Either way keep us posted on what you find on it [electrical or fuel].

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes

At this point I it seems to be working fine. I have tried numerous scenerios in starting, shuitting down, waiting and starting. Each time it restarts imm ediately. Either I somehow fixed the problem by touching, jiggling, tapping and tightening every wire connection or component or it is not fixed and one day it will just not start up. I will just make sure my kicker motor is in good condition.
On another note, while the boat has been sitting the dang steering froze up. The motor swung fine so I new it was the shaft that was stuck. Anyway after trying numerous techniques to unstick it with no success, I got the torch out(no not what you think). After heating up the metal pipe the shaft slides through, it freed up easily and came out clean. The shaft is very clean with no corrosion at all. I simply cleaned it up and applied new grease. It seems as if the marine grease just dried up and turned to clay. I had been greasing this regularly so I am surpised this has happened. I am wondering if the grease I used is from China and if there is a better grade marine grease available?

 

[sidenberg]

Re: Force 1987 125 HP doesn't start sometimes

What about the rectifier? On outboardignitions.com the troubleshooting guide mentions for no spark problems to disconnect the rectifier and if engine fires replace the rectifier.

 

[Jiggz]

Re: Force 1987 125 HP doesn't start sometimes

I use triple guard grease which is very heavy but also effective since it rarely dries up and hardened. Additionally, once a year when I grease I triy to push out as much of the old grease as I can. This is to ensure you replace the old grease with the new one. It doesn't take that much to do it.