[rszarko]

Hi Guys,

I've got two 1995 Mach 1 670's recently. Both in excellent condition.

One runs really well, very fast. The other runs but nowhere as fast.

Symptoms of under performing sled:

Chews up more fuel and oil then the other.
Bogs at low rpms
Can't get the Rpm higher than 6000 when full throttle
Engine was recently rebuilt
Compression is good in both cylinders
Occasionally but rarely back fires.

My gut tells me it's getting to much fuel.

Is there anyway to easy adjust the mixture level?

If not, anybody know a good ski doo mechanic in Hamilton area?

Rick

 

[TwinsofMLB]

There are many adjustments that can be made on a roundslide carb. You may want to have it serviced if you don't know what you're doing. Personally, I'd just clean both of them and replace the gas. Sounds like you have some moisture in there.

 

[smallengineguy]

How do the spark plugs look? Are they black and sooty?

 

[rszarko]

Plugs are black sooty

Yup. I just pulled the plugs last night and they are black and sooty.

What do you think?

Rick

 

[BC_Dan]

I would jet one size smaller on the main jet, then run it again. If the plugs remain black, you can jet even smaller for that temperature and elevation. Plugs should be cardboard brown. Black means too rich which robs power and wastes gas.

 

[smallengineguy]

AAlso make sure the primer isn't leaking by on that one, or if it has a choke, that the plungers aren't seized open in the bores.

 

[Mach 1 /93]

How do you check to see if the primer is leaking by? I have a 93 Mach1 670 and it won't keep running and the plugs are soaked can it be the primer?

 

[smallengineguy]

Once it is running, pinch off the supply line to the primer. That wil stop fuel from leaking by.