Very Weak Or No Spark!!!

[SYCHOWAND]

hi all am hoping someone can help me out with my johnson v4 90 circa 1990 serial # bj90tlesb please read on am at my wits end grrrrr so initial problem was a broken piston ring on no1 have fitted new piston and new rings to the other three and all relevent gaskets and seals and a new impeller kit for good measure! only to find after refitting the power head that it wont start it seems to be sparking on both starboard plugs a very weak spark on the lower port side and no spark on the top port plug obviously all were good prior to power head removal i have three wires which i am not sure where they go one is a short black with a round bolt on connector near the starter solonoid i imagine this goes to the earth post on the engine block there the other is also black with a round bolt on connector which comes in as a double cable with the main harnesses then splits via a bullit connector would also reach the earth post with a bit of persuasion this wire looks as if it could have lighter marks or a stripe! the third is a long green wire in a black shroud that reaches round to the thermostat hoses. if these cables are not the problem what could a complete layman like myself of done wrong or damaged? many thanks sorry for the long post lol ps when cranking it locks up if i over choke it is this normal or is something seriously out with the timeing? again many thanks

 

[VaBlue]

Re: Very Weak Or No Spark!!!

To replace the pistons, et all, you probably have a manual. It should have the wiring diagram which will tell you exactly where the wires go. I wouldn't put too much stock in wire colors in case somebody re-wired it some other time, but the wiring diagram is what you need. Otherwise, since you do get some spark, did you do the timing adjustments?

 

[SYCHOWAND]

Re: Very Weak Or No Spark!!!

hi ty for replying yes i do have the manual but its hard to follow especially the electrical side also i dont have access to the correct testers as for timing adjustments i didnt realise i had to! if you could explain how to do this id really appreciate it. also i have a standard multi meter is this any use? cheers!

 

[daselbee]

Re: Very Weak Or No Spark!!!

Hi,
The PP is working for half of the engine. I would re-look at the connectors between the stator and the power pack, and those between the timer base and the power pack. Look for corrosion, look that they are plugged all the way in, and look that the pins are not pushed back into the rubber boot.

And get those unconnected wires back to where they should be.

I bet on the power pack to timer base connector....

 

[VaBlue]

Re: Very Weak Or No Spark!!!

I have no idea how to do the timing for your engine (it may not even need it), the manual has to explain that to you (or someone smarter than me). As for test tools, the multi-meter can be used for resistance, but I believe voltage checks require a DVA adapter (for digital meters, don't know about analog). You should also get a spark gap tester and compression gauge if you'll be doing the regular maintenance on the motor. Timing adjustments will require a timing light from any car parts store.

Read the 'top secret' thread for the tune-up needs of your motor once you get the spark problem fixed up. So, like Daselbee said, make sure every wire in the motor is in good shape. It's amazing where corrosion can get in an older motor...

 

[SYCHOWAND]

Re: Very Weak Or No Spark!!!

hello again i managed to get it started this weekend the lack of spark on the port cylinders was due to bad connections due corrosion on both coil packs! phew so glad it was something simple. but now have a new problem lol you wont believe this but after finally getting it started it wont switch off from the key grrrrrrrrrr lol have to flood it with the choke to get it to cut out am sure its down to the spare wire left over after refitting the power head! the manual is no use here so again am at your mercy many thanks for any help!!!!

 

[daselbee]

Re: Very Weak Or No Spark!!!

The black/yellow stripe wire is the kill wire. It connects from the pack into the harness, travels up front thru the big red cannon plug, and is grounded when the key is in the off position at the ignotion switch. If the wire's path is OPEN for some reason, no shut down.
That last wire wouldn't be black/yellow stripe would it?

 

[SYCHOWAND]

Re: Very Weak Or No Spark!!!

no its green and runs in a black plastic shroud! see 1st post above cheers

 

[SYCHOWAND]

Re: Very Weak Or No Spark!!!

thanks again all shes running fine lack of spark was down to bad / corroded connections at the coil pack and a break in the black yellow lead for the kill switch happy boating!