Missing at idle after high rpms and spark plug question

Hello,

I am having a minor problem that so far is more of an inconvenience than anything else.

My 115HP 2-stroke 1995 idles fine, I ran it for the first time in over a year. It ran fine at all RPMs.

After about 1 hour of running I was docking and when I went into neutral it would hiccup and die.

I restarted fine and it would randomly hiccup and die in neutral. It was idling in neutral at about 900 rpm (normally it's 10-11). Putting it in reverse against the docklines and it would idle at about 600-700 and never missed or died for 10 minutes. I thought this was weird.

The next day I went back and it idled like a champ, even in neutral, but I didn't have time to take it out.

The only thing that's weird is since I unhooked and checked the upper oil pump I have about 100:1 (slighlty less) oil in the tank and the oil pump is also working. Could this be due to too much oil?

Also I have one question on spark plugs. The normal plugs for this engine are B8HS-10 - 1mm gap. When I got the motor it had BUHXW-1 surface gap plugs. It would not run with the recommended plugs. Since then I hav e changed the coils and spark plug wires and it seems fine (motor runs better than before). Are there any drawbacks to running with the surface gap plugs? I don't want to change too many things at once if everything is ok. Also the surface gap plugs seem more robust.

Thanks
JP

[boats.net]

The hiccup usually means it's running too lean which means carbs need to be cleaned.

[Hamfisted]

Clean out the idle jets !

If it sat for a year without being run I can guarantee you the idle jets are clogged up with old fuel residue. Remove the idle jets ( the small brass screws on the lower edge of the carb bowls....) and clean them out with stainless leader wire and carb cleaner. Also spray carb cleaner up into the holes they came out of to clean out the bowls. If you have Amsoil Powerfoam that's the best cleaner out there. Next to that I would recommend Berryman's Chemtool Spray (Walmart or any autoparts store...).




- Mike

I did rebuild and fully clean the carbs before this season. It idled fine before running at high RPMS.

The problem is still there after running 2 days this weekend (10-12 gallons of fuel) it runs great at fast idle and higher

I'll try to reclean the jets. It seems weird it only appears in neutral and never in gear. Just to check are the jets the long brass screw with the orange o-ring?

Any ideas on the spark plugs should I stick with the surface gaps that are in there? Or switch to the recommended plugs?


Thanks
JP

[boats.net]

Those are the high speed jets, low speed jets are in bottom of float bowl under small screw in bottom. I would use the B8HS-10 plugs.