1984 9.9 HP ignition problem

[GrassKutter]

I've noticed the spark plugs are fouled badly the last few times I've been out. The last time the engine would not start after shutting it down to fish.

I brought it home and put new plugs in and ran it for about an hour. Would not re-start. I put a checker on the plug and it is dead.

I removed the flywheel and looked things over there. Cleaned the inside of the flywheel, etc. I did notice a few drops of wax like stuff on the block under the Sensor Assembly.

I put it back together and still no spark.

That was yesterday ... I've read through this forum and got a notion that it might be the kill switch so I disconnected it. Started right up ... thought it was fixed .... put stuff back together and la de da .... no spark.

Any ideas??

thanks

 

[James R]

Re: 1984 9.9 HP ignition problem

That kill switch or the wiring could be the issue. I assume that once the motor is running it stays running. Disconnect the switch and run the motor if it will start. You can stop the motor by choking. If it will start ok after that it could be the switch. I would also consider the neutral start switch as another source of your problem.
Your dirty plugs is another thing. Could have the wrong plugs, could be the idle is set too rich, could be the carb float is set up incorrectly,your choke is not fully open.

 

[GrassKutter]

Re: 1984 9.9 HP ignition problem

Thanks

I actually cut the black wire on the kill switch.

I started the motor this morn while it was cool. Once the motor warmed up it died and would not re-start?? There is no neutral switch that I know of.

I'm thinking the Sensor assembly is bad but I don't even know what the sensor does?? Both cylinders go dead so I don't think it's the coils but it could also be the ignition coil.

Next week I'm going to replace the sensor and all the coils.

thanks for your input

 

[CatTwentyTwo]

Re: 1984 9.9 HP ignition problem

I have the same motor and the manual has a few things that you can check with an ohmmeter. If you disconnect the 4 wire connector between the armature plate and power pack, you can check the charge coil and sensor coil. On the armature end of the connector, if you read between the A and D pins, a good charge coil will read 575 + or - 75 ohms. Between the B and C pins, a good sensor coil will read 40 + or - 10 ohms. You can check for shorts by clipping one meter lead to the armature plate and then testing the A, C, and D pins. Any reading other than an open circuit indicates a shorted coil or wire.
These ohm readings are for a cold motor, a warm motor will read higher.

 

[GrassKutter]

Re: 1984 9.9 HP ignition problem

A-D Pin is 520
B-C Pin is 37
no shorts

Do you think these readings are far enough off to cause a problem

thanks

 

[CatTwentyTwo]

Re: 1984 9.9 HP ignition problem

According to the manual, those are acceptable readings. They are within the plus and minus tolerances for a good coil. You can also check the ignition coils by disconnecting the 3 wire connector between the power pack and coils. On the ignition coil end of the connector between engine ground and pin B you should have 0.1 ohms and the same for pin C and ground. Between pin B and the spark plug terminal of the top coil should be 275 + or - 50 ohms and the same for pin C and the plug terminal of the bottom coil. The plug wires themselves should be near zero of course. If everything checks out and you can get it to run again, you could repeat these tests if it dies and won't start. Maybe some weird reading will show up. One other thing that I would try for the heck of it is, next time it dies or will not start, install new or at least clean spark plugs and see if that makes any difference.

 

[GrassKutter]

Re: 1984 9.9 HP ignition problem

BINGO!!

I checked and re-checked the readings a dozen times. The reading for grnd to pin b & c is 0 on most of my checks.

The readings between the terminal and b & c is 235, however it is 235 on both b&c regardless of which terminal I'm hooked to. In other words, with one wire of my meter hooked to the top terminal I get the same reading, 235, on both terminal b&c.

Maybe shorts in the coils??

Thanks

 

[CatTwentyTwo]

Re: 1984 9.9 HP ignition problem

It looks like that is normal, I just checked my motor and I get the same thing. On the top coil, between the terminal and either B or C, I get 245 ohms. On the bottom coil, I get 240 between the terminal and either B or C.
Have you tried changing plugs yet? You mentioned fouled plugs originally. I had a problem years ago. I motored out to go fishing and as soon as I slowed down, the motor stalled and would not start again. I put in new plugs and it started right up and trolled fine but when I sped up and moved to another spot, it stalled as soon as I slowed down again and would not start. Same thing, put in clean plugs and it fired right up, I made it back to the ramp where it stalled again. The problem turned out to be my original steel fuel tank. It was full of rust on the inside and that had messed up the carburetor, the plugs were getting too fouled to fire. A carb rebuild and new plastic tank cured that problem.
I have only had one other problem with the motor. It was running fine when I stopped it one day, but when I started it a few weeks later, one cylinder was not firing. New plugs made no difference. The mechanic I took it to replaced the power pack and it has been trouble free ever since. Unfortunately, the manual does not provide any ohmmeter tests for the power pack.

 

[GrassKutter]

Re: 1984 9.9 HP ignition problem

Thanks for all your info .. very helpful

I put everything back together with new plugs as you suggested) and the motor fired right up. I want to check the coil readings on a hot engine. but .... when it rains it pours ..... the water pump failed!!!

I took the lower unit off and checked the impeller .... looks good ... the impeller housing is not scored .... put it back on and it still doesn't work ....

do you know if it makes a difference which way the impeller fins are bent on re-assembly??

thanks again

 

[Rick.]

Re: 1984 9.9 HP ignition problem

Yes it matters. From the top looking down, the motor turns clockwise so the water pump vanes point counter clockwise. They fallow if that makes sense. I just changed mine and the impeller looked fine to me but it wasn't pumping worth beans. You should take a good look at the water pump assembly. If the case or plate are scored (polished is ok) it would be a good time to change those parts too. Glad to hear you were back up and running even though briefly. Rick.

 

[BaitThrower]

Re: 1984 9.9 HP ignition problem

I found I had to have the motor in a vertical position when putting th lower leg back on. Ensure the copper water uptake pipe inserts into the rubber grommet on the water pump housing successfully (use a small bit of grease on end of copper tube and inside grommet to make liefe easier) then insert leg vertically and have someone or something hold it in place while you attach the shifting rod correctly, then keep it all vertical and add and tighten the lower unit bolts equally and evenly so the leg rises up evenly and the copper tube doesn't bend/block/close off the pump grommet as the leg is tightened. I had to do this over half a dozen times before I realized how important keeping everything need vertical on re-assembly was (at least on my outboard).

 

[GrassKutter]

Re: 1984 9.9 HP ignition problem

I want to thank all of you for your tips and advice. I really appreciate it.

Motor is outside purring like a kitten. Starts right up. Water pump and recoil fixed.

Turns out I have a faulty kill switch!! The darn thing works most of the time and then it just decides to ground out the coils for a while and then resumes working..... go figure

thanks again

 

[BaitThrower]

Re: 1984 9.9 HP ignition problem

I want to thank all of you for your tips and advice. I really appreciate it.

Motor is outside purring like a kitten. Starts right up. Water pump and recoil fixed.

Turns out I have a faulty kill switch!! The darn thing works most of the time and then it just decides to ground out the coils for a while and then resumes working..... go figure

thanks again

Hi mate,

Occassionally I suffer a similar thing. Won't restart. I think i might alsohave a twitchy kill switch. Can you PM me with quick details of how you checked that out or how to fix it? Thanks