Got an 89 sp 587 single carb has spark and won’t even fire with fuel done the cylinders?

[Big tex 120]

Had it running rough for a small amount of time was told it ran last year has 120 psi both cylinders not high but should be enough, lost spark replaced coil has good spark now and still nothing?

 

[lavasioux]

Hi Big Tex,

Hmm this is an interesting one...

Have you seen the spark from the plug, like held the plug against the head to see it spark?

Have you rechecked compression? Only take a stroke to knock a hole in a piston.

Timing? Has the timing been messed with?

Hmmm... veryyy interesting indeed.

Good luck!

 

[Big tex 120]

Just checked spark and still 120 and yes I have spark from the plugs , but I’m honestly not sure on the timing did get it running a few days ago but wouldn’t stay running long or would be real rough and wouldn’t run on its own well

 

[lavasioux]

Ok, then fuel is the likely culprit-

Time for a carb rebuild with Mikuni kit?

 

[Big tex 120]

Still nothing even with fuel in the cylinder tho?

 

[lavasioux]

I could be mistaken, but liquidy gasoline is more likely to short the spark than it is to actually fire.

 

[lavasioux]

Air box/filter/intake is clear of rodents, acorns, and old hamburgers?

 

[Big tex 120]

Yep it’s all clean

 

[mikidymac]

If you have spark and a little fuel down the carbs will not fire it then it is the low compression.
You need compression , fuel and spark to run.