Intermittent firing on number 3 cyl.

[Keith Buchanan]

1989, 50hp.<br /><br />New plugs, leads, swapped round coils and input output wires on CDI unit. Problem did not move, have good compression, new fuel, new fuel pump.<br /><br />Not knowing what the setup under the stator is with the trigger, could this have failed in any way that would affect just one cylinder or could it have become loose in any way which is causing this intermittent problem. Is the trigger one unit or is there three of them. are they Hall effect triggers or optical.<br /><br />With this problem being intermittent I have disccounted the cylinder and having swapped everything else around the only items left in my mind are the stator, kill wire (surely these would affect all three cylinders) and the trigger.<br /><br />Any ideas Guys.<br /><br />Regards Keith B....

 

[Trent]

Re: Intermittent firing on number 3 cyl.

Most likely you have a bad CDI pack. You need to do more testing. web page

 

[KCLOST]

Re: Intermittent firing on number 3 cyl.

You can ohm out the trigger leads... Need a manual for the proper readings....

 

[dolluper]

Re: Intermittent firing on number 3 cyl.

make sure your switch boxes are properly grounded'then discontect your trigger leads on a 3clyinder between brown andwhite/black 100 scale should be 11-14 between white and white/black 100 scale again should be 11-14 then between violet and white/black 100scale be 11-14 On 4 clinders only two different leads 100 scale reading between 7-10 as tests above

 

[ebubeck]

Re: Intermittent firing on number 3 cyl.

Are you sure it is a spark problem and not a carberator problem?

 

[Keith Buchanan]

Re: Intermittent firing on number 3 cyl.

Cdi pack great and I already swapped the carbs a while ago, next stop is flywheel off an have a look. Low and high speed windings must be okay otherwise it would affect all cylinders. I am still drawn to the trigger.<br /><br />Thanking all you guys, this is one hell of a site..Keep smiling from sunny Blackpool......Keith B.............

 

[dolluper]

Re: Intermittent firing on number 3 cyl.

The test I posted above is the trigger test with an ohem meter set on rx 100 scale those specs are for 50hp V thunderbolt ign no need to pull the fly yet , did you test the coil for that cylinder ,bad connections or GRounds!

 

[Laddies]

Re: Intermittent firing on number 3 cyl.

The only things that will effect spark on one cyl. The Ign coil(not very often) trigger I have never replaced one on a 50 hp. the most often replaced part on that engine is the switch box hope this helps

 

[Keith Buchanan]

Re: Intermittent firing on number 3 cyl.

All checks out okay with ignition circuit.<br /><br />Something I have picked up on from another post is that I may have a knackered lower end cap seal. The plug on numer 3 looks too clean and number two isnt as dark as number 1. A while ago I had the drive shaft stuck at the splines and it took 3 weeks of beating off, maybe this has compromised the seal.<br /><br />Regards Keith B..

 

[dolluper]

Re: Intermittent firing on number 3 cyl.

yes you probably screwed the o-ring or seal for sure ,check your exhaust cover gaskets and seperator also,exspect some broken bolts