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Discussion Starter · #1 ·
Hi all,

Fixing up my first sled ever 1994 Ski Doo Mach 1 670 with the help from the shop manual. So far I've flushed the gas tank, put new gas lines in and cleaned the crap outta carbs, new plugs. Rides and runs great besides a couple things below.

  • Fuel leaking out the overflow lines on MAG side. I've cleaned carbs a few times and finally decided to buy new gaskets/jets for it (yet to be put on). Hope that fixes it. I may have got carb cleaner on some of the rubber parts. I believe I followed all the tuning correctly per manuals.
  • Non of the gauges on dash work. Fuses ok. All electrical connections look fine... At least the lights work properly.

How far will a full tank go? I know there is variables but ball park me please.

I'll write back after I change out gaskets and jets in the Carb to see if that stops overflow. Otherwise I guess I'll look into the pumps?

Thanks for any feedback.
 

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Just my opinion, but gas mileage will vary based upon your riding style and what conditions your riding in. I would guess if your trail riding and not super aggressive on the throttle you could probably get 10-12 mpg. That's what I typically get on my 02 600 if I remember correctly. Off-trail and playing in deep stuff it would obviously be less due to track spin. Others should chime in with real-world experience.
 

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I had a '94 Mach 1 I bought new and rode for the '93 /'94 season. At 90 miles after starting out with a full tank of fuel I was looking for the next spot to fill up and hoping it wasn't too far away. After changing the jets when the engine was broken in I upped it to 100 miles.

Lynn

Replace those needle and seats along with the gaskets to stop the flooding. If you end up with a base full of fuel and try to start the engine you are going to be replacing a connecting rod.
 

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Got a chance to take it apart today, simply dirty needle and jet. Could have just cleaned it and put the old one back but since I had the full rebuild kit i threw in the new n/s and gaskets. Tried taking the pilot jet out but didn't have the right size screw driver and stripped it. Guess that's staying in there for now, any advise on getting that out? ran nice without any overflow though. Lots of smoke though to start then goes away.
 

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I drove a 94 for years.i was always having trouble with dirt in the needle and seat.so I put a filter on each hose from fuel pump to carb problem solved.
 

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Got a chance to take it apart today, simply dirty needle and jet. Could have just cleaned it and put the old one back but since I had the full rebuild kit i threw in the new n/s and gaskets. Tried taking the pilot jet out but didn't have the right size screw driver and stripped it. Guess that's staying in there for now, any advise on getting that out? ran nice without any overflow though. Lots of smoke though to start then goes away.
Too bad on the jet, I keep a dedicated correct size screwdriver just for that. Tough fix. If you screw up trying to drill it, you wreck your carb.

If it continues to smoke for a while after it sits, you likely have leaking inner crank seals. Rotary valve seal possible but less likely. Depends how bad it is to whether you address or not, major job if crank seals. Just keep an eye, can be bad if it fills up the base after long term storage. If not serious you can just not worry about it.
 

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Discussion Starter · #8 ·
I drove a 94 for years.i was always having trouble with dirt in the needle and seat.so I put a filter on each hose from fuel pump to carb problem solved.
When I flushed the tank, the gas lines in the tank were completely dissolved and filters fell off. So I put new lines in the tank with filters, also put the in line filters on as well when replacing all gas lines. That's why I couldn't believe it still got clogged. After riding a tiny bit still holding up so think it was just the last of the old stuff.
 

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Too bad on the jet, I keep a dedicated correct size screwdriver just for that. Tough fix. If you screw up trying to drill it, you wreck your carb.

If it continues to smoke for a while after it sits, you likely have leaking inner crank seals. Rotary valve seal possible but less likely. Depends how bad it is to whether you address or not, major job if crank seals. Just keep an eye, can be bad if it fills up the base after long term storage. If not serious you can just not worry about it.
Yeah, need to find one of those screwdrivers. It's seems clean enough so hopefully being stripped won't screw anything up.

After running around a bit it smokes less, but doesn't completely go away. I guess I'll keep an eye on it. I always shut my gas line valves off when not running so maybe that has prevented the crankcase from leaking too bad if that's it? Maybe I'll take that apart in the summer to check it out if I get the free time. Or would a compression test let me know how bad it is/isn't before getting into all this?
 

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No, the fuel has no effect on what I was talking about. The rotary valve cavity in the center of the engine is always full of oil from your injection tank. If all the seals are not good, oil can seep either internally into the bottom of the crankcase and get burned when you start it up, have also seen the rear rv seal leak into the intake tract, front rv seal will leak out the weep hole to the front of the engine, externally.

Anyway, don't worry about it, just keep an eye on it and keep the oil full. It may not be that at all or not serious, don't want you to get panicked on it. There is a pressure test that you could do in the off season, we can walk you through it if needed.
 
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