1991 75hp 3 cylinder help!

[Gary H NC]

This motor has me yanking my hair out!
It had no spark so i replaced the switch box. It now has spark but won't fire a bit.Not a pop sputter or nothing.

I pulled the flywheel and found that one of the magnets had been glued back on with 5200...
The stator has some scuff marks from the magnet.

This motor had just been rebuilt, about 10 hours of use then stopped running.
The guy that charged 4k for the rebuild is no longer around.
He did tell the owner that after the break in period it would need the timing set? Not sure what was up with that.

The owner wants it running even if they have to buy a new flywheel and stator.
It does have spark but it seams kind of weak to me.
It looks like the stator is not centered because the glued on magnet only scuffed one side..

Any opinions?

 

[Gary H NC]

Re: 1991 75hp 3 cylinder help!

Bump......any ideas guys?

 

[jhodge]

Re: 1991 75hp 3 cylinder help!

You da ADMIRAL. Have you done the resistance test on the stator and trigger? Have you tested the coils? Are the plugs in good condition? When my engine just spins its usually a fuel problem. Either over enriched and wet plugs or no fuel to the cylinders. Have you checked if a bit of fuel thru the plug holes gives a pop when cranked? Maybe a reed problem with no fuel getting to the cylinders. Just some ideas, Good luck. JH

 

[Gary H NC]

Re: 1991 75hp 3 cylinder help!

Thanks JH,
Have done the tests and the stator gives odd readings.different each time.
It still has spark to the plugs though.
It is getting fuel,the plugs are new and the coils and wires tested good.
New switchbox..
The motor will not fire,pop,spit or sputter.I tried the fuel in the cylinders and sprayed premix in the carbs.
I assume the flywheel is junk because of the magnets glued back on with 5200.That and the fact it rubbed the stator.
I have a guy thats going to let me try a used stator and flywheel that he knows is good.

 

[jhodge]

Re: 1991 75hp 3 cylinder help!

When I bought my setup I had spark at the plugs. but later after reading the manual I found that the stator was trash. Didn't know it, but the firing sequence had been messed up by previous owner. Replaced the stator and still would not start, althought it did bark, buck and misfire. Discovered the mixed up wires and that made a world of difference. Not suggesting that your sequence is off but think the path of stator and flywheel will be very revealing, or the cause of more hair pulling. JH

 

[Gary H NC]

Re: 1991 75hp 3 cylinder help!

I was thinking the same thing about the stator.It is like its firing at the wrong time. That might be from the glued magnets and the stator is chewed up.
The stator took a good beating from that rigged magnet.
I have my fingers crossed that the new flywheel and stator will at least get me a pop or sputter..
Thanks for your input!

 

[jhodge]

Re: 1991 75hp 3 cylinder help!

Its my understanding that the stators part in ignition is to supply an AC charge to a rectified condensor in the switch box where it is stored until needed. I think this process repeats all the way thru one revolution, thus supplying multiple charges to the swithch box. If this part of the stator is not functioning properly then my guess is that the stored charge is minimal or non existent. When the trigger passes its magnet then it sends a signal to the switch box to fire the plug. This fire process involves the stored charge in the switch box being sent to the primary windings in the coil which excite the secondary windings in the coil and make a high voltage charge available to the high voltage wire to the plug. Anything wrong along this described path could cause a problem with the plug firing or firing at the wrong time. But as I understand it you have NO firing. So pick a part or test, test test. At least you have a continous problem, the intermittant ones are real fun to find. When the plugs are under the pressure of compresson I think they have more difficulty in discharging (firing). So a plug that fires out in the open does not equate to a plug that fires under compression. Good luck JH

 

[Gary H NC]

Re: 1991 75hp 3 cylinder help!

Thanks JH,It makes perfect sense to me.
The boat is hanging in a lift so its been hard to work on.
I found a trailer to use later in the week so hopefully once i get it on land i can test and work on it better.At least swap out the flywheel and stator and go from there..