'86 Johnson 90hp won't fire

[dmack04]

I have a '87 Johnson 90 hp. motor on my Skeeter. This motor has been serviced every year for the past 3 years. I tried to start it after a 3 month lull, and it backfired once, and now won't start. It gets spark to the plugs. I'm getting fuel passed out of the fuel filter (which was a little dirty), but still no start. It seems as though the primer doesn't get fuel into the carburator when it get's pushed. You can hear the primer engage, but if fuel was getting in, it should fire. I noticed that the fuel filter drains after a gush of fuel. I don't detect any leaks at all.<br /><br />Does anyone have any ideas?<br /><br />Thanks in advance for any help.<br /><br />/Dave

 

[JB]

Re: '86 Johnson 90hp won't fire

Howdy, dmack.<br /><br />Start here: http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000001 <br /><br />If that doesn't find the fault, come back and tell us what you found.<br /><br />Good luck.

 

[dmack04]

Re: '86 Johnson 90hp won't fire

JB,<br /><br />Can you tell me how the Flywheel Key being sheered creates a problem? If you are getting some spark while holding it against the engine block, how does the fly wheel affect that? This would be a timing thing at this point, correct?<br /><br />Thanks for your reply.<br /><br />/Dave

 

[JB]

Re: '86 Johnson 90hp won't fire

When a flywheel key shears it changes the timing between the flywheel magnets and the stator, dmack.<br /><br />The most likely result is loss of spark or weak spark but it can also cause mistimed, or "maverick" spark in some engines.<br /><br />Actual consequences differ from engine to engine.<br /><br />Your Johnny should be able to jump a hot, blue spark 7/16" to 1/2".

 

[Joe Reeves]

Re: '86 Johnson 90hp won't fire

Usually when a engine (2 stroke outboard) sits for any length of time, a problem such as you describe is due to fouled carburetors. However, engaging the fuel primer allows fuel to enter the crankcase directly between the carburetors and the reeds/leaf valves.... in which case, if all else is as it should be, the engine would run as long as the primer solenoid is engaged.<br /><br />The sheared flywheel key scenario would allow spark but at the wrong time, resulting in a loud backfire from the exhaust outlet of the engine.

 

[dmack04]

Re: '86 Johnson 90hp won't fire

Yes, I think the next step is to get some fuel mixture directly into the carburator. Do I need to open up the carburator or can I access this elsewhere? There is a cover on the front of the motor where air flows in. Is it possible to do this from there?<br /><br />/Dave

 

[inohv8]

Re: '86 Johnson 90hp won't fire

If you want a fire? sure go ahead.. best is to remove the cover, and breather cover , open the butterfly(s), squire a bit of fresh gas mix.. but first before you do that, sniff some fresh gas mix and some of what you have been using.. if the gas you have been using smells anything other than the fresh gas, then that probably your problem, it is full of varnish. If you squirt some gas into the carbs, stand back while you start , it might be rich but if you have spark, it will fire or backfire or misfire..

 

[dmack04]

Re: '86 Johnson 90hp won't fire

Thanks inohv8, I can't say that I ran the engine out of gas last time I ran it, but I can say I am using fresh gas to try and start it. Last year I had the carburator serviced, but to your point, there could still be varnish.