92 Formula Plus Won't start - Snowmobile Forum: Your #1 Snowmobile Forum

dpawl31 · 10-31-2009, 07:52 PM

So I have a 92 formula plus that won't start.

We went through the carbs, I am not sure where to set everything but I set them even and the same they were when they came off. I think the air screw on the side is 2.5 turns out, and idle is set high.

The day we got it, it popped once. Waited like 2-3 hours, pop again.
Nothing more than a single pop.

Cleaned carbs... same thing.

There IS fuel getting to it via primer AND fuel pump.

Spark is there as well, need to find out how to check how strong?

Anyway... we had to ghetto-rig the pull start.
Was testing that when the carbs AND exhaust were off - forgot key was in...
We are used to 4 strokes.

Started up... revved out of control, and shot across the yard.

Stalled right before pushing the skis through the shed.

My friend reached for the kill switch first - realizing its just two wires, went for key and thats when it shot across the yard.

Me on the other hand, first instict was OH MY GOD ITS GONNA BLOW.
So I turned and ran. hahaha.

That all took only about 4-5 seconds.

Anyway, so we know the motor runs... and revs very well, lol.

What in the hell is going on?

The fact that it ran and ran across the yard rules out spark issue and such to me... I just don't get why I get ONE pop... then nothing for a while after it sits.

Otherwise, the sled is amazing... in great shape. Suspension is perfect, gauges all work, lights nearly all work... the track has seen better days but still very usable, at least a season left on it.

This is my first sled... it's exactly what I want, and it was only $50... lucky find for sure.

Any ideas what is going on?

stangcruzin · 10-31-2009, 09:28 PM

Are the carbs working properly?Check the slides and make sure they are not stuck partially open.(throttle cable sticking,needle jet not seated properly).And is the gas turned on??
Oh yea,try to start it on a stand next time.It'll be easier to catch..........LOL

dpawl31 · 10-31-2009, 10:29 PM

Yes carbs are fine.

Got used to carbs fixing my Yamaha Maxim 650 motorcycle (4 carbs)

Fuel is flowing into carbs.

All I get is one pop.

Not a few pops, ONE.

It's like it's starved for air or something.

I have the idle screws in enough that the pointed part is in the barrel, and the stem of the idle screw is about 1/4" in the barrel.

No luck tweaking throttle either.

Does not seem related to that.

Maybe the spark is only strong enough to fire once and die?

dpawl31 · 11-01-2009, 07:18 PM

Soooo we just tried to get another pop out of it, before I went to do the compression test.

Uh, it fired... and ran... and took throttle... and revved, and track moving...
lights all on, oh my god...

It's feeling really boggy sometimes, but it ran and I could keep it running.

I have NO IDEA where the base settings are for these carbs.

I have only tuned Hitachi CV Carbs.

I assume the little green air screw is responsible for the idle mixture?

And not sure how far in the idle screw should be (the one that holds the slide up)

Oh - and the airbox was not on. And the exhaust was barely pinned in place.

Once I get the box on, the exhaust tightened up...

Where should I go from there? Base settings for carbs?
Is there a way to drain the old oil?
What about draining the gas tank? Or should I just top off with some real good fresh 93?

**smallengineguy** · 11-01-2009, 09:27 PM

The air bleeds (smaller screws) should be roughly one turn out. The idle screws should be turned together so it idles around 1800 RPM's. Fill it with fresh fuel and run it. Check the plugs for a dry dark brown color.

dpawl31 · 11-02-2009, 11:48 PM

I bought the manual online.

The photos are terrible (scanned) but its nearly 600 pages of awesome.

The manual said to screw the idle screws in till the slide is gently lifted, I have to re-read it to see if there was a height involved.

Would fresh oil help, or does it really not matter? That oil could be real old.
But the coolant that was in it when I bought it was bright green and gorgeous.

**smallengineguy** · 11-03-2009, 06:11 AM

Oil won't matter.