Mariner 15 misfire

[simonafloat]

Just a minor niggle with my Mariner 15 2 stroke. Noticed the last couple of times out.

It starts fine from cold but runs on 1 cylinder only for a very brief while when we pull away. After that the second cylinder kicks in and everything works great for the rest of the trip.

Worth checking out or is it just one of those things with 2 strokes? Replace spark plugs? Cleaning them beforehand makes no difference.

Thanks

Simon

[Fenlander]

Are you really sure it's just firing on one or is it a general missfire?

Not known it on either of my Mariner/mercury 15s or the near identical Mercury 10.

Simplest and cheapest is to fit new plugs and check plug leads are clean and look OK plus that coil connections are corrosion free and tight.

Also if you have one do a compression test.

Then go from there if it still does it. I would probably then fit new plug leads before worrying about more serious ign/mechanical issues.

[simonafloat]

Originally Posted by Fenlander

Are you really sure it's just firing on one or is it a general missfire?

Not known it on either of my Mariner/mercury 15s or the near identical Mercury 10.

Simplest and cheapest is to fit new plugs and check plug leads are clean and look OK plus that coil connections are corrosion free and tight.

Also if you have one do a compression test.

Then go from there if it still does it. I would probably then fit new plug leads before worrying about more serious ign/mechanical issues.

Cheers. just ordered new spark plugs as I have never changed them since I took ownership of the engine so no idea how old they are. Bought these: | eBay

Any idea if they come with the correct gap?

Simon

[simonafloat]

Originally Posted by simonafloat

Cheers. just ordered new spark plugs as I have never changed them since I took ownership of the engine so no idea how old they are. Bought these: | eBay

Any idea if they come with the correct gap?

Simon

...and yes, it could be a general misfire, difficult to tell. But it goes from misfire straight to full smooth power instantly after about 20-30 seconds of throttle, then as I say no problems for the rest of the day.

Simon

[Fenlander]

Plugs with the code that ends in 15 are pre-set to the correct 1.5mmm gap... but I always check them!