96 yam 115B - idle/cylinder question

[LewisB]

I'm scratching my head over this one....

Took boat out yesterday, started it up as normal and immediatly motored out at just above idle, sounded rough and after a couple of minutes it stalled, did this twice.

I started it again and it sounded better, took off the cowling and pulled the ht lead off the plugs, one at a time. What i find strange is that 3 of them made no difference but when i pulled the bottom stbd one, the engine cut. I proved this a couple of times. just holding the lead caused me to get a shock from an ark (much to the amusment of my mates!)

So i had only one cylinder firing? At idle does this engine cut down to only one cylinder? The cap to this plug has been loose and I had tightened up some time ago.

I then took it out and it ran at full WOT with no problems at all and idled fine.

Is this a sign of the coil/ht lead breaking down or is the arching a sign of damage?

Looking forward to some advice!

Lewis

 

[smartcaddie]

Re: 96 yam 115B - idle/cylinder question

hey Lewis this has happened to me before.. in my case it was a loose plug boot and was not making a good contact.. but if it really is giving you problems and you do a low test after its warm and doesn have any power to the plugs i'd say its a ignition coil. before you do that check your voltage regulator or CD box, make sure you are getting the right readings

 

[LewisB]

Re: 96 yam 115B - idle/cylinder question

Thanks for the reply smartcaddie,

could you explain more what you mean by a low test please.

when you had this issue, did it show itself in any other ways, sometimes the engine loses about 1000rpm for a few seconds and then comes back - wonder if the loose plug boot could be the problem.

Lewis