had spark then lost spark

[goodtimesfishing]

ok so I have a 1988c 50hp force and had no spark from one of the coil modules. I have a spare parts motor and took a coil module from it and when I installed it, I had great spark from both coil modules. So I start motor today and it starts right up and runs for maybe 10 seconds--probley more like 6 seconds and it dies, I try to restart and sounds like no spark. So I check for spark and have none in either cylinder. I look at wiring diagrams I have and notice I have diagrams that show 2 different ways to wire from trigger to coil modules????? wires coming from trigger is as follows:
one shows green/white(trigger) going to orange the other shows greeen/white going to green
red(trigger) going to green on one diagram and orange on the other diagram
green(trigger) going to green on both wiring diagrams
orange(trigger) going to orange on both wiring diagrams

does this make sense to anyone??maybe it can be wired either way I don't know
I just want to make sure wires are correct before proceding, also does it have any familiar sound as to what may have gone wrong.

 

[pnwboat]

Re: had spark then lost spark

The voltage from the trigger is low AC voltage so it really doesn't have a polarity. It can be wired either way if it's the original trigger. If you have any doubts you can try it both ways. The most important thing is to make sure the pair of wires from the #1 trigger coil are routed to the #1 coil module and the same thing for #2. As for no spark on either cylinder, I'd undo the last thing that I did. Disconnect the coil module that you just installed and see if spark returns to the other cylinder.

If no change, take a look at the engine Kill switch and associated wiring. You can eliminate the kill circuit by disconnecting the brown wire from each coil module at the terminal block. If spark returns, you've identified the problem area. Note: If you start the engine with the brown wires disconnected, you will not be able to shut the motor off with the key. You can choke it until it stalls or if you're brave and don't mind the possibility of getting shocked, you can pull both spark plug wires off while it's running.

 

[goodtimesfishing]

Re: had spark then lost spark

I will give that a try...I have a parts motor but don't want to just start changing parts, afraid I might fry or damage a good part. Also just want to confirm something....a multimeter with the hold function, can that be used to test parts? I know a DVA is ideal, but will the hold function give me any better reading then just a standard multimeter? Thanks for any and all help

 

[pnwboat]

Re: had spark then lost spark

You could use a multi-meter with a hold function but you probably won't get the readings that are published in the trouble-shooting charts. One other thing to consider is the stator. It generates the AC. voltage for the coil modules. Very easy to check it with a standard OHM meter. You should have 680 - 850 Ohms between the two blue wires coming from the stator. Make sure that you disconnect the stator wires so that the other circuitry doesn't interfere with your readings.

 

[goodtimesfishing]

Re: had spark then lost spark

can my problem be caused by the rectifier? I just took the rectifier off and tested it with ohm meter and I get nothing in any direction, nothing from the base(ground) to the ground terminal even.????? This shouldn't effect the spark though should it, just the charging I thought???

 

[pnwboat]

Re: had spark then lost spark

A bad rectifier can cause poor spark, but I've not seen it cause zero spark. Yes the rectifier is primarily for charging the battery, but the charging coil in the stator is close to the winding that generate the AC voltage to the coil modules. I would think that if the rectifier was the culprit, it would read as a short, not open. I could be wrong though.

Depending on the type of ohm meter you're using and the setting, you may get mis-leading results when testing the rectifier. You should have a plus "+" symbol by one of the terminals, a minus "-" symbol on the opposite terminal. The other two terminals should have a wave "~" symbol next to them. Put your meter on the lowest range for OHMs. Check between the + terminal and the two ~ terminals in both directions. Do the same thing with the - terminal and the two ~ terminals. One direction you should get no reading, the other direction you should get a reading as you switch lead polarity between the + and both ~ terminals. Same thing between the - terminal and both ~ terminals.

 

[goodtimesfishing]

Re: had spark then lost spark

So I decide to pull the flywheel to give the stator a visual check and low and behold the problem is found......I have heard of it happening but never saw it before...The magnet spins on the inside of the flywheel. At first I thought it looked funny because the 2 ends of the magnet did not line up, so I went to push it back into place, it slid right down, so I try and pull it out and it came right off!!!!!

So now a question, can that magnet strip be reinstalled succesfully??? I have a spare motor and the puller is on it right now (wow is it tight, letting it set with presure and wd 40 for a minute while I post this) I am sure I will get it off, but the original one looks much cleaner and free of any rust(one from parts motor has slight rust on the teeth)original one looks brand new. should I try and glue it back on there with some kind of glue????

 

[pnwboat]

Re: had spark then lost spark

Good catch! Yes you can glue it back on. Clean the bonding surface on the inside of the flywheel so that it's free of any debris or rust with a wire wheel and drill. Wipe off with some acetone, carb cleaner, or anything to get rid of any oil that doesn't leave a residue. Most any heavy duty epoxy based adhesive will work. I've used JB Weld, PC-7, Devcon. The PC-7 (ACE Hardware) is nice because it is very thick and doesn't run very much. The JB Weld and Devcon are thinner and have a tendency to run.

 

[goodtimesfishing]

Re: had spark then lost spark

that is great to hear because I still can not get the other flywheel off, so I will epoxy it back on, however that will have to wait till tomorrow. I will post how it goes.
pnwboat- thanks for all the help it is very much appreciated.

 

[Frank Acampora]

Re: had spark then lost spark

While the puller center bolt is torqued down hard, either smack the center bolt of the puller a couple of good shots with a heavy hammer, or heat the center of the flywheel with a propane torch.

If you have an air gun, use it to torque the puller center bolt. The multiple impacts on the puller will usually pop the flywheel easily.

 

[goodtimesfishing]

Re: had spark then lost spark

I will have to try that, also I don't have a torch but would a heat gun help maybe? I guess it wouldn't hurt. I will let you know how it goes.

 

[goodtimesfishing]

Re: had spark then lost spark

Ok, so I glued the magnet back in place with some epoxy and put everything back together and it started right up. It did seem to drop a little what I believe was magnet dust or shavings, below the flywheel. I am hoping this is normal or maybe not normal but ok. The way that magnet goes all the way around the inside of the flywheel does not leave much clearance between magnet and stator, however I made sure when assembling it, that it would turn freely(not bind with stator)
As for the flywheel on my other parts engine, after soaking in wd-40 all night I put the puller on it again and did not have to hit it or add heat, just popped loose as I tightened the puller(did not even have to get it as tight as yesterday) However that flywheel has rust and I notice that the magnet on that one is coming loose at the ends. Must be a commone thing with those.
Anyways-thanks for all the help. Next I am installing a new impeller.