1988 85hp Loss spark on all cylinders

[BluejayII]

Hello, I have been reading this forum for a while, have found lots of usefull info. This is first time posting problem. I have 1988, 85 hp, model no# 856x8B, serial no# 3191. I have replaced impeller, thermostat, fuel pump diaprham, and spark plugs, also rebuilt carbs this year getting ready for season. Finally got around to starting it up for first time, n ow my problem is no spark on any cyl., I put timeing light on it no spark, then for short time had spark and lost it again without doing anything. Battery is fully charged, checked kill switch everything seems as should be. I had same problem last year at lake, after running all day Sat., went to start up Sun. and would not start, I checked everything I could think off gave up and went back to campsite and had a beer. After arranging for a tow to launch, tried one more time and motor started up like nothing ever happened. While winterizing had no problem starting. Sorry for the long winded post, just trying to give as much info as may be needed

 

[eurolarva]

Re: 1988 85hp Loss spark on all cylinders

Start with checking all connections for loose wires and corrosion. Also inspect all wire insullations to verify you are not shorting to ground. If you can get it running with a tank try looking for an arching wire when it is dark out. Also check points to verify they are clean and gapped correctly.

 

[BluejayII]

Re: 1988 85hp Loss spark on all cylinders

I checked wiring found if I moved 2 wires I would get spark, the white kill wire and purple tach wire at terminal block on port side of engine. I removed and put new connectors on these wires and motor fired right up. It was running for about 20 minutes while I was adjusting carbs and motor stalled out, lost spark again. Checked these wires and they are ok. Checked and rechecked to make sure that white kill wire was not going to ground(I even disconnected both wires to no avail) Spent next two hours checking and rechecking wires and also rechecked resitance at stator and trigger wires it was still within specs. This one really has me stumped, I have went over wiring schematics and cannot trace what could be causing this problem. Engine ran good while it was running, timing was right on the marks, good water flow, etc. Anyone out there ever have this kind of problem? Any ideas would be greatly appreciated.

 

[BluejayII]

Re: 1988 85hp Loss spark on all cylinders

^Today I checked for any loose or damaged wires, used analog meter instead of digital. All grounds were ok. Found that both white wires going into CD packs had no resistance to ground while cranking motor, I had disconnected the wires from terminal so they were only going to packs, is this normal? According to everything I have read these wires should only go to ground with key in off postion (or safety switch pulled). Just cannot figure out what I am missing.

 

[BluejayII]

Re: 1988 85hp Loss spark on all cylinders

^Checked stator and trigger leads separetely to ground no continuity, could packs or coils be shorting to ground?

 

[BluejayII]

Re: 1988 85hp Loss spark on all cylinders

^Update after checking stator and trigger ohms checking ok but no voltage found that the rubber magnet on flywheel had come loose. Pulled flywheel and reinstalled magnet using Marine Tex. Put it all back together and it fired up immediately.

 

[roscoe]

Re: 1988 85hp Loss spark on all cylinders

Thanks for the update. It is now valuable info added to the archives, for future use.<br /><br />Happy boating.