3.0 loss of spark

[airshot]

I am new to I/O's so sorry for any dumb questions. i have been an outboard man for 40 yrs so this I/O thing is new. I thought mt shift interupter switch may have gone bad, here is the scenario. Engine died frequently but not always when going in or comming out of reverse (docking) but did restart right away, then began having difficulty restarting, then would not start after sitting for awhile (fishing). Found there was no spark, jumped a hot wire to coil and engine started immediately. Last time this happened we developed a miss on the way back in, sounds like ignition not fuel, could the shift interupter switch be causing this type of problem? Thanks in advance for your attention, I have been reading the many posts on this switch and I believe it may be the culprit. Thanks

Airshot

 

[cannonford57]

Re: 3.0 loss of spark

interupter switch would be a go nogo situation....you didnt say what year your engine is but if it is an early one it may just be a set of points and wires w/plugs will take care of your problems

 

[Joshua Nichols]

Re: 3.0 loss of spark

I would change the points and condenser if so equipped... Cheap and easy to do.. I have had a condenser cause all kinds of weird stuff happen. They get hot and quit working.. Sometimes a coil will get hot and take a dump. Then when they cool off start working again, but I would change the points and condenser first.. Fresh set of plugs are always good too..

 

[Don S]

Re: 3.0 loss of spark

here is the scenario. Engine died frequently but not always when going in or comming out of reverse (docking) but did restart right away,

Sounds like you have a Merc alpha type outdrive. and that you need a new lower shift cable.
Read this thread and I think you will understand why.
http://forums.iboats.com/showthread.php?p=1930449#post1930449

 

[airshot]

Re: 3.0 loss of spark

Thanks for the replys, should have mentioned the ignition system has been converted to electronic, point and condenser are gone, engine is 1983 and seems to be in great condition ( compression good, purrs like a kitten at idle, uses no oil) outdrive was rebuilt two years ago, I can only assume the cable was good or replaced. When it acts up there is no spark at the coil or plugs, yet when a hot wire is touched to pos on coil it fires right up. If not the shift switch how about the coil? Never had one go bad so I don't know how they act when dying. Problem was ocassional but is becomming more frequent, happened last two times out. Thanks again for all the good info on this forum.

Airshot

 

[airshot]

Re: 3.0 loss of spark

Sounds like you have a Merc alpha type outdrive. and that you need a new lower shift cable.
Read this thread and I think you will understand why.
http://forums.iboats.com/showthread.php?p=1930449#post1930449

Don,
Thanks for the reply, yes I have read that a couple of times, but here is my bit of confusion...if the shift cable was bad, would it keep the coil grounded indefinetly? I thought it may be the problem at first, but then I lost spark no matter where I moved the control lever and had to jump coil with hot wire to fire. Other posts indicated the switch was only momentary and would reset itself.....Thanks

Airshot

 

[Don S]

Re: 3.0 loss of spark

It's possible, a simple test would be to look at the switch and see if it's activated.

 

[Don S]

Re: 3.0 loss of spark

Last time this happened we developed a miss on the way back in, sounds like ignition not fuel,

You might also try disconnecting your tach (Gray wire on - side of coil) and see if the miss goes away. Tachs can short internally and kill spark.

 

[Adirondack]

Re: 3.0 loss of spark

Bad resistor to the ignition? Heats up and quits? cools down and passes current?

 

[nola mike]

Re: 3.0 loss of spark

When it acts up there is no spark at the coil or plugs, yet when a hot wire is touched to pos on coil it fires right up.

Airshot

don't think it's your switch; if the switch was always closed, i don't think you'd start, hot wire or not--your ignition would still be grounded. when you disconnect the jumper wire after it's started, does it kill the engine? you get power to coil from 2 sources; 12v directly from the solenoid when starting, otherwise via the ignition through the resistor wire.

 

[airshot]

Re: 3.0 loss of spark

don't think it's your switch; if the switch was always closed, i don't think you'd start, hot wire or not--your ignition would still be grounded. when you disconnect the jumper wire after it's started, does it kill the engine? you get power to coil from 2 sources; 12v directly from the solenoid when starting, otherwise via the ignition through the resistor wire.

Yes the motor continues running after removing the jumper wire, runs fine like nothing ever happened. Does this electronic conversion system use a resister wire, coil with internal resister, do not see an external resister. I just read a post on the ignition switch will be looking at that as well. Thanks again for all the replys!!

Airshot

 

[Adirondack]

Re: 3.0 loss of spark

Yes the motor continues running after removing the jumper wire, runs fine like nothing ever happened. Does this electronic conversion system use a resister wire, coil with internal resister, do not see an external resister. I just read a post on the ignition switch will be looking at that as well. Thanks again for all the replys!!

Airshot

Check the small connections on your starter solenoid for clean and tight. Check for 12v at both small terminals when cranking. Depending on the setup a bad solenoid or bad/broken connection can prevent the ignition from getting voltage during crank. When you jump it your bypassing that system, then once running you can remove the jumper and it runs off the normal run circuit.

 

[airshot]

Re: 3.0 loss of spark

Progress report.....
Removed and checked the shift switch, it is working, cleaned all connections, checked all wires to be sure none are broken or damaged.
Checked coil, it has 12v power when cranking and around 7 volts in running position. Cleaned connections at solenoid and adjusted shift cable. Cable moves freely and appear to be in very good condition. Of course it starts and runs fine in the drive on muffs as it always has, guess we will have to wait until we get it back on the water. Thanks for everyone's suggestions and if anyone has any other ideas to check out, I would love to hear them....

Airshot

 

[airshot]

Re: 3.0 loss of spark

Sunday evening update.....got a chance to get the boat on the water, started and ran perfectly for about 30 minutes then started breaking up, even stalled a couple times but did restart. After sitting at idle for 15/20 min gave it some gas and it took off like nothing was wrong....for about 20-30 min then started breaking up again, let it idle for about 15 min then it took off like nothing was wrong. Temp is staying at 125degrees (checked with another gage) so overheating is not the problem. After the same time span it started breaking up again ( 2400 RPM) disconnected the tach wire but still same problem. This time I gave it more gas and it seemed to clear itself out at 3500 RPM and up, throttled back to 2400 and after 30 min started again, throttled up again..after doing this four or five times it then ran fine for the rest of the evening. What are my options, coil?, fuel pump which is less than two yrs old? bad fuel? Or electrical breakdown? Any suggestions would be greatly appreciated. Thanks in advance.......

Airshot

 

[airshot]

Re: 3.0 loss of spark

Update on motor issue, looked at throttle plates in carb saw what I thought might be water spots, removed water seperator filter and yes it was totally full of water!! Cleaned it out and drained the fuel tank. I believe my loss of spark may have been some loose/dirty connections but the engine miss/loss of power was from water in fuel. Next outing will tell for sure. Also found the fuel tank vent was improperly installed and could have been allowing water in when hitting bigger waves, corrected that as well.

Airshot

 

[moparmatt]

Re: 3.0 loss of spark

That really sounds like a coil to me. A coil will fail in two ways ,either not work at all or when it gets hot it will quit working. I would almost bet the ranch on the coil.