50 hp Timing

[JDusza]

I have a 1986 50 hp that I cannot start. I have verified compression and spark. I have cleaned the carburetors and believe I should at least be getting a cough.
When spraying premix into the carburetors or cylinders, still, nothing. Completely nothing.
This has me wondering if someone rotated the flywheel out of phase with TDC. I do not have a timing light.

If compression, spark and fuel were anywhere near close, I should get something. I suspect the timing is out so far that the spark is letting go without compression. I don't know how to test for this without a light.

So, I was wondering what the assembly position of the flywheel is against TDC. I can get to TDC rotating the crank. From there, at what position should I place the flywheel?

Right now, with cylinder #1 at TDC, the index points to about 10 on the fly wheel hash marks. I have no idea what this means.

Thanks,
J

 

[JWH0420]

Re: 50 hp Timing

Well only way to tell much of timing setting is w a light and correct proceedure but i would doubt timing is the issue... when u check spark are u using an inline tester because it takes more voltage to start a spark under compression than on the side of the block a weak coil may b to blame... another thing would be if your plugs are fouled or damaged

 

[JDusza]

Re: 50 hp Timing

Something doesn't seem right. I am confused. I also hate to think timing is the issue, but I have done everything else. I should at a minimum be getting a fart when spraying premix into the cylinders or carbs. I get nothing.

The ignition is stator, trigger, switch box, coil and spark plug. There is no distributor. The coil gets energy from the stator and the trigger says when to fire. The signal generator for both stator and trigger is the magnet in the flywheel. There are no mechanical adjustments to the timing, other than mis-assembling the flywheel to collar at the top of the crank, so why the need for a timing light?

All the hardware is fixed position, is it not? Does the trigger assembly have an adjustment for spark advance like on the tall sixes? I don't recall seeing it?

It seems to me there would be assembly instructions for installing the flywheel while cylinder #1 is at TDC. A long time ago, before electronic ignition, one would see a "zero" mark on the flywheel to correspond to TDC. In this case, a timing light just tells you that you are nowhere close to being correct. I think I should be able to judge timing by bringing cylinder #1 to TDC and looking at the index marks on the flywheel against the pointer. This is a lot less work than dragging out a timing light.

I am checking spark with an air gap spark tester. Spark is jumping about 1/2" air gap.
A weak coil would be 1 out of 3. I would expect a cough or rough running.

Of course, could be wrong.... something is indicating I am ....
J

 

[JWH0420]

Re: 50 hp Timing

ive not had one of these igintion systems in my hands before but looks to be somthing like the trigger plate assem is triggered by crank shaft not the magnets on the flywheel and i would assume timing is controled by positioning of the trigger plate from some sort of linkage im sure there is some form of timing adjustment being 2 cycles hafta retard the timing excessivly to idle. what were your compression readings, are your plug wires in correct sequence and if there is no distributor there is more than one coil be sure to check that all coils can produce sufficient spark. other thing to check is that ur reeds are closing if there is no "pulse" inside case it wont draw a fuel charge in and spark is irrelevant

 

[JDusza]

Re: 50 hp Timing

Ok.
I have to look at the motor again to verify trigger adjustment.
Compression was 120 in all 3.
Plug wires 1 to 3, top to bottom. Top coil fires cylinder #3, middle coil fires cylinder #2 and the bottom coil fires cylinder #1.
All coils produce spark to jump 3/8" air gap.
Would I see reeds failure to close on compression numbers?
I forced premix fuel into both carburetors. Then, I sprayed premix fuel into cylinders directly. Still no fire.
J

 

[Faztbullet]

Re: 50 hp Timing

Typical sign of weak stator output.It needs to jump a 5/8 gap with a bright blue "snap" as what is happening is compression is preventing spark to jump plug gap. Even with it out of time you would get a "pop" out the carbs or exhaust.

 

[JDusza]

Re: 50 hp Timing

Thanks for the feedback! I am wits end with this one. Killin' batteries and wearin' out the starter. After days of cranking, I got one back-fire pop. I thought I had burned off fuel and would go, but, nothing, still. The owner knows nothing. Claims it ran 2 years ago. The latest sticker I see is '09.

I'll check spark again, but I thought I was okay. Can I measure a bad stator? There must be a minimum output spec? (?).

I want to go back to basics on assembly for I find it way too easy for another party to have taken off the flywheel and not gotten it back on in its original spot. An unwary set of hands can take this out to left field. The design is unbelievable.

If I were to build up the block, I would probably bring #1 to TDC and then set the flywheel indexed to "something". I should be able to check that without a timing light.

Faztbullet, let's assume the spark is ok. I know it may not be, but I will verify. What else could cause this? Can you help with the mechanical set-up question?

Thanks for the help.
J