Outboard Motors

[Ken Juul]

Mine died a week ago.  '90 2 cycle nissan 5 hp.  Rebuilt the carb, that is usually the cause.  Nothing.  Had spark, fuel, but not running.  Called a few shops.  They suggested a bad head gasket, beyond my cruising cababilities.  Weathered in today, asking on the dock they recommened the outboard shop.  Hauled it up and asked them to trouble shoot.  They assumed that my carb rebuild was good and started looking other places.  Checked the spark...it was there...checked the compression...it was good.  Being raised on 2 cycle engines they tried a new spark plug.  Started on the second pull.  His explaination was sparking in open air is much different than when under compression.  Been playing with engines for several decades...never heard that before.  A spare plug is now on my shopping list.   $28 for parts and labor is so much better than $2300 for a new engine   and where would I put the engine hoist on my all ready crowded stern.

[lazybone]

I'm jealous cause I'm never that lucky.

[Jim Hardesty]

I raced dirt motorcycles doing my own work for a lot of my younger years.  Unless I knew that the problem was something else, the spark plug got changed, next step would be to change the new plug again.  I experienced more than a few bad new plugs.  Having said that I do only have one spare plug for my dinghy outboard.
Jim

[Indian Falls]

The resistance of air goes way up  under compression.  Sometimes causing the arc to occur way up inside the plug rather than at the electrodes in the case of a fouled plug or a possible defective one.  It take 10,000 volts to jump 1/10 of an inch at sea level. What is the compression on a 2 cycle?  14:1?  If your coil is weak, and the plug is good it wont jump at all under compression but in the air, no problem.

[Ron Hill]

Guys : Just remember that on all aircraft with reciprocating engines - each cylinder has TWO spark plugs!! That aught to tell you that ignition is the biggest problem and not carburation!

With that said I had trouble with my 2 cycle in that it would not idle smoothly anymore, but ran great at faster speed.  After screwing with the carburetor/cleaner/new gas/ etc. - I finally changed to a new sparkplug and all the problems went away!  And I knew better than that to start out with!!

So step #1, when you have trouble with your outboard, lawn mower, weed eater and gasoline engine - change to a new spark plug!! 

A (pain savings) thought

[Stu Jackson]

So step #1, when you have trouble with your outboard, lawn mower, weed eater and gasoline engine - change to a new spark plug!! 

A (pain savings) thought

I agree.  There is one other thing one should check, and happened to me.  One weekend it took 60, yes 60 pulls to start our outboard!  Twice!  Both times I pulled the first 59 times and then my friend Dave, and then the next time another firend also named Dave (true story!) came by and pulled the 60th time and it worked!  Both Dave's said: "So, what's your problem!?!"  Funny guys...

Turned out the wiring to the kill switch was wonky and once repaired it works just fine.

So, spark plug(s) first, then the wiring.

[patrice]

Hi Stu,
What happened to me last summe, on a saturday morning, get into dinghy and try to start, pull, pull re-pull for quite a while.  Got feed up and used the oars to get to shore.
When got back to dinghy, pulled did not want to start.  Look at it and saw that I had forgotten to put back the safety key in......... oupssss  don't tell anyone ok...   

[Stu Jackson]

Look at it and saw that I had forgotten to put back the safety key in......... oupssss  don't tell anyone ok...   

OK, I won't tell...'cuz I did the same thing...