force 120 no spark on 2 cylinders

[chevyguy420]

i have a 1990 force 120 with no spark on cylinders 2 and 3. so far I have replaced the stator and now the trigger with no luck. what else can I check before buying more parts? thanks

 

[The Force power]

Welcome to IBoats :welcome:


Here's a link that will help you with diagnosing the ignition;

https://www.outboardignition.com/page8.asp

 

[chevyguy420]

thank you! I will try disconnecting the kill wire to the pack and see if the does it.

 

[The Force power]

thank you! I will try disconnecting the kill wire to the pack and see if the does it.

Cylinder #1 +#2 get power from pack #1
Cylinder #3 +#4 get power from pack #2

If your #2 & #3 are not firing you would have to remove both kill wires from both packs!

BUT;

Start with RE-checking your wiring Hook-up if correct first... IF......all is right, then swap the #2 wire from the pack to #1 Coil & #1 wire from pack to #2 wire from coil to see if #1 stops firing and if #2 starts firing??

inspect the spring inside the spark plug boot, they tent to rust! clean as necessary

Make sure your are working with a TESTED good battery & Starter !!! You need to have the cracking amps for the fly wheel to produce enough RPM's to create enough voltage for Spark

Make sure; you have all plugs grounded at all times when testing!! failure to do so can/will result in damages cdi/swtich-pack(s)

Keep us posted

 

[chevyguy420]

thanks for the reply! i have checked all the wiring and it is all hooked according the wiring diagram I have. it has a 1 year old battery in it that is good and the starter is also good. I disconnected the wires from #1 cylinder and put them onto #2 and I had no spark on either one, and same thing when I did with 3 and 4. I disconnected the kill wires and it was the same thing, ran on 1 and 4. I disconnect the wire from the pack to the cdi and swapped 1 and 2, then I had spark on 2 and not on 1. so I'm thinking its probably the power packs, is it common for them to fail only on one cylinder?

 

[The Force power]

This is bit of a stretch........ disconnect the two wires from stator that go to the Rectifier off & see if the now coil packs fire

 

[chevyguy420]

thanks again! I disconnected the wires from the stator to the rectifier and it fired up, on 2 cylinders but the tach didnt work. I'm off to work now, more playing around tomorrow I guess. I happened to find the exact same motor with a grenaded piston I'm going to buy for parts.

 

[jerryjerry05]

Get a spark tester.
$7 AutoZone
Use it on each cylinder.
Your timing light might not be picking up the
signal and showing the cyl. spark???

 

[The Force power]

thanks again! I disconnected the wires from the stator to the rectifier and it fired up, on 2 cylinders but the tach didnt work. I'm off to work now, more playing around tomorrow I guess. I happened to find the exact same motor with a grenaded piston I'm going to buy for parts.

When you say it fired up, you on two cylinders? I thought you said that you had spark on two cylinders already??
IF...you are planning to hang on this motor, buy as many spare parts motors you can!!

The Tach. wont work when one lead of the stator wire is not connected to the tach.(you can hook it up) leave the rect. bypassed

 

[chevyguy420]

sorry if my reply wasnt clear. when I disconnected the stator wires it would only spark on #1 and #4. I have continuity through the cdi and plug wires( 1 cdi is original, 1 is newer with a removable plug wire, which also has continuity). I installed new plugs and cranked it over and checked each plug separately(with a plug that works) so I know #2 and 3 are not sparking. in the driveway with muffs on it fires right up and will rev up to 5000rpm no problem but as soon as I put it in the water under load it barely makes it to 2500 and wont get up on plane or anything. I did have it looked at and the mechanic said the same thing that its only got spark on 1 and 4 and recommended replacing the stator. so that was first thing I tried with no luck, then the trigger and again no luck. the problem started when I overheated while trying to fly my manta ray tube

 

[chevyguy420]

I'm starting to be hesitant on buying this parts motor, as I might be better to just save up over the fall and winter and repower with a 150. I just want to get on the water and enjoy the rest of summer lol. thanks for the help everyone, is there a way to test the power packs on my bench or is just a continuity test?

 

[chevyguy420]

today i have rechecked all the wiring and after changing the wires from the trigger from cylinder 1 to cylinder 2 to the power pack I still had no spark on cylinder 2(same thing with 3 and 4). I then changed the wires from cylinder 1 to cylinder 2 from the power packs to the cdi and had spark on 2 and not 1(same with 3 and 4). I found a cdi ignition troubleshooting guide that says it's the power packs. looks like I'll be buying this motor after all as it's the cost of 1 power pack but is a complete motor minus a piston lol.
thanks again for all the help I will update this post when I get the parts and am hopefully out on the water

 

[The Force power]

I'm confused??

 

[The Force power]

today i have rechecked all the wiring and after changing the wires from the trigger from cylinder 1 to cylinder 2 to the power pack I still had no spark on cylinder 2(same thing with 3 and 4). I then changed the wires from cylinder 1 to cylinder 2 from the power packs to the cdi and had spark on 2 and not 1(same with 3 and 4)

This not make any sense???

Hook everything back up the way it should be...... then switch the wire coming out of the CDI power-pack going to the coil of spark-plug#2 ON #1 and visa versa SEE if #2 start firing
Do the same with #3 to #4

 

[chevyguy420]

yes sorry that's what I did. and the when I swapped the wires it fired on 2 but not 1 and same with 3 and 4.

 

[The Force power]

Okay, so now we know for sure the Spark plug coils are good and both CDI power-packs only work for only one cylinder each.
So........it looks like you need two power-packs
I would buy the "spare" motor for parts (providing the ignition is good) this way you'll have an extra LU and many extra expensive parts. lol

 

[chevyguy420]

thanks for the help! its greatly appreciated, and sorry for my confusing comments.

Pin it to win it!

 

[The Force power]

Pin it to win it!

I like that! you should put this in you signature below

 

[jerryjerry05]

Try switching the packs around and see if the
same problem exists?