Are you sure the spark plugs are being fouled with oil and not fuel? You can simply smell the fouled plugs and know.

 

Thanks for the reply! I’m sure it isn’t gas, I’m a mechanic for both trucks and cars. And when I put some of the fluid of the spark plugs on the floor it doesn’t burn. So I’m positive it’s oil. Thanks again!

 

Thanks. Is the oil pump connected to the throttle system and synchronized?

 

English isn’t my first language, so sorry for any misspelling or misunderstanding. If you mean that the throttle of the carbs and the oil pump ”lever” goes up and down at the same time then yes they are. Thanks

 

When the crank chambers fill with oil, they are difficult to keep running. It also poses a risk of hydro-locking the piston. I remove the carbs and snake a hose under the piston to siphon the oil with a vacuum pump.

 

Yes I will, but I have to get to the cause of it filling with oil. Could it be the inner seals that I didn’t position right?

 

During the install they can be sliced from the sharp edges of the crankcase. It is worth performing a engine leak-down test.

 

All right, thanks for the answer!

 

Note the oil tank has two outlets. Does the oil tank drain on its own until it reaches the higher outlet then stabilizes there?

 

I’ll need to refill with oil to check, thanks

 

Before siphoning the oil, I must have pulled the cord a hundred times. It is surprising how fast the plug can foul from excess oil. One day I built a leak-test and found the leak through one of the two oil lines going into the engine. As a temporary fix, instead of disassembling the engine, I installed a ball valve in one of the lines, the one that stops leaking when the oil reaches the line. If you show me a picture of the oil tank with the oil line coming out of the side, I can confirm which one it was. With consecutive years of low snow, the project went on the back burner. When I got around to it, I was unable to find the leak again. I tore it apart and found no evidence of any seals broken or cut.

 

I tried it without enough oil to reach the hoses to the water pump and the rotary valve, still fouling the plugs with oil. So I don’t think it’s the inner crankshaft seals. Could the oil pump be fault by any chance?

 

Yes, it will still foul the plug with a filled crank chamber. Monitoring the oil level is only to determine by what hose it is leaking.

For the possibility of leaking though the oil pump, there should be check valves between the oil pump and where it pumps. Remind me where the two small oil lines from the pump are going to. Do they go the crankcase or the intakes?

 

They go to the intakes, 2 small holes. I can’t blow through the end of the hose where the banjo bolt goes. So I can’t blow through the lines from the oil pump to the Intakes

 

Going back to the pump synchronization, if I understand things correctly, if the throttle cable to the pump is connected with too much slack in the cable, then the pump can pump too much oil.

So this needs the be checked.

 

I have disassembled the oil pump and checked so nothing is stuck or something’s broken, everything seems intact and I assembled it by the worskhop manual. So it should work. I understand how the mechanism work now so it should be set correctly

 

Looks good. In the first video we can see the air bleeding through the oil lines. The bleeding procedure is to simply hold the level at its maximum position.

 

Thanks!

 

Center seals on crank are leaking . Probably on the O D . I’ve seen this before cause of old sealant on then . Or they are not in the groove properly

 

Hello! I’m new to both this forum and to snowmobiles, and I’m looking for some guidance regarding my 97 skidoo formula 583 stx. Bought it used in February this year and it was already torn apart. Head and cylinders removed as well as the engine from the chassis. Split the crankcase to change outer seals and check the bearings. Bearings didn’t feel bad so just changed outer seals. Changed pistons and piston rings. After the rebuild it won’t start, I don’t know if it did before the previous owner tore it apart but I have gotten it to run for about 5 seconds with tons of smoke. Checked everything, ignition timing, floats, carburetor adjustments, rave valves and rotary valve. Changed sparkpnugs too. The rave valve had a small tear in it that I glued together just to see if it made any difference. It didn’t. I can get it to run for about 2 seconds on starter fluid before the sparkplugs get full with oil. I’m thinking I may have not put the inner seals on the crankshaft at the right place or that my oil pump is leaking. Any ideas? The middle of the oil pump is also full of oil. Under the oil pump gear. Any help or tips is greatly appreciated!

Center seals on crank are leaking . Probably on the O D . I’ve seen this before cause of old sealant on then . Or they are not in the groove properly

I’m going to tear apart the crank case today, I still think that I didn’t put the center seals in the right grooves, didn’t think about them when assembling, only the outer ones. So I’ll look.

 

Don't use too much starter fluid or too often. It tends to wash the oil off of cylinder walls.

 

This. My FIL sprayed a tractor for about 10 seconds. The muffler on top of the hood exploded and split apart at the seam big enough you could put your hand inside it. It sent the rain flapper to the moon, never did find it..

Take the carbs off and FULLY disassemble them, Jets out, air screw, take the slides off the throttle cable, everything apart. Take note as to what jets go in which carbs. OR disassemble one at a time, or mark which side is PTO and which is MAG side. I have two plastic containers with clear lids I use for parts storage. I can lay the whole carb inside it. One labeled PTO one MAG.

Soak in cleaner for a few hours (I use a very good OMC branded carb foaming cleaner) (works great for cleaning RAVE valve slides as well). Find carb adjustments in the shop manual, lay a clean cloth or paper towel across the work bench and reinstall everything as per the book.

Rebuild or replace the fuel pump.

 

the little nipples just back from the clamp are the inlets for the primer lines. Right now, if it runs, it sucking air from there.

Re-read your carb settings and start from scratch.

VM38mm carbs (right?)
Red circle, thats a bowlvent. Is your primer hooked up to that? If not, where is that line going?
Yes, if your primer is hooked up there it'll overflow and quit.

In the video, it appears to me that your primary fuel lines are needlessly long. Which may or may not hurt anything, but its more the pump has to push.

Carb slides set to spec? I forget the spec off the top of my head. A few mm. Use a drill bit for a spacer.

https://www.skidoopartshouse.com/oemparts/a/ski/500c6346f87002314436f9c2/fuel-system-583

Add some more photos, the video is hard to see where you have what plumbed


You never (IMO) get a 2 stroke not to smoke, so dont use that as a barometer of it running right or having too much smoke. Also, its jetted (hopefully correctly) to run a much colder temps, so as now (not knowing your ambient temps) it'll be running rich and smoke more and be more difficult to tune.

Pic of inside the carb where the slide snaps closed? Showing the whole opening.

 

the little nipples just back from the clamp are the inlets for the primer lines. Right now, if it runs, it sucking air from there.

Re-read your carb settings and start from scratch.

View attachment 2100963

VM38mm carbs (right?)
Red circle, thats a bowlvent. Is your primer hooked up to that? If not, where is that line going?
Yes, if your primer is hooked up there it'll overflow and quit.

In the video, it appears to me that your primary fuel lines are needlessly long. Which may or may not hurt anything, but its more the pump has to push.

Carb slides set to spec? I forget the spec off the top of my head. A few mm. Use a drill bit for a spacer.

https://www.skidoopartshouse.com/oemparts/a/ski/500c6346f87002314436f9c2/fuel-system-583

Add some more photos, the video is hard to see where you have what plumbed

There is 2 of the inlets/outlets that you circled, the primer goes on the right side, at least from what I could tell in the manual. So that’s just a overflow hose I think. Or is it supposed to be connected to the hole near the clamp?

 

Take the plugs out. Clean them. Dry with a propane torch or similar. Better yet a new gapped set, Don’t put them back in the motor, install in spark plug cap, ground them on the head and pull the starter. Get spark?
Is an STX electric start or not? I forget.

Key, tether cord and kill switches in proper positions?

 

Take the plugs out. Clean them. Dry with a propane torch or similar. Better yet a new gapped set, Don’t put them back in the motor, install in spark plug cap, ground them on the head and pull the starter. Get spark?

This procedure is a good start, but only shows that the ignition system is basically functioning. This test does not show that the spark voltage is adequate to fire a compressed fuel-air mixture.

The test used to show adequate spark voltage is to place the metal end inside the spark cap about 1/4"-3/8" from a metal surface like the head. The spark should jump that large gap in open air if the voltage is high enough to fire the compressed fuel-air mixture.

 

Yes, that is quite a bit of water! Do you have ethanol in your fuel or not?

 

Nope, just regular Swedish pump gas

 

I am glad that you figured it out, because I completely missed the potential for so much water in the tank. Burning all that water probably decarbonized the pistons and rings lol

 

Worse thing would have been if that froze inside the tank. You’d have been screwed.

water is what, 11 or 12 lbs per gallon. Has to be a gallon or two of water there.

The fuel that’s in the container, shouldn’t be that color. Did you mix oil in the fuel? Even then, it’d be a different color. Perhaps it’s a coloured container?

glad your up and running.

 

Used a old pump I have used to drain oil out of cars, so there was some left in the pump. Thanks

 

The fuel that’s in the container, shouldn’t be that color. Did you mix oil in the fuel? Even then, it’d be a different color. Perhaps it’s a coloured container?

That is a color seen when fuel is old and oxidized.

I am glad that you figured it out, because I completely missed the potential for so much water in the tank. Burning all that water probably decarbonized the pistons and rings lol

Yeah, earlier, I almost asked my usual question about 'Is the fuel fresh?', but did not. Need to get back into that habit.....

 

Yeah, earlier, I almost asked my usual question about 'Is the fuel fresh?', but did not. Need to get back into that habit.....

It is a tough one as some things become repetitive and rarely the case. It is a catch 22 phenomenon. I wonder if you have noticed that the more times you mention something like old gas, the more times new topic posters will mention having fresh gas for example. Over time this becomes standard practice. New topic posters have typically done their research and seen those standards establish. When posting consistently over the same forum, such progress become apparent over time. I find it fun to see such a good group like on this topic. It takes forever to build. We lost a large number of knowledgeable people on both SDI forums which at the time had a significant impact.

Did you take a close look at the opening picture of the video in Post #61 ? The sled was near the eave where much rain would collect. I find we got lucky to have an owner who gave us the full story. That makes all of the difference. I bet those kids find their Dad pretty cool.

 

The fuel that’s in the container, shouldn’t be that color. Did you mix oil in the fuel? Even then, it’d be a different color. Perhaps it’s a coloured container?

That is a color seen when fuel is old and oxidized.

I am glad that you figured it out, because I completely missed the potential for so much water in the tank. Burning all that water probably decarbonized the pistons and rings lol

Yeah, earlier, I almost asked my usual question about 'Is the fuel fresh?', but did not. Need to get back into that habit.....

Fuel was fresh but filled it the day after a rainstorm I didn’t know about. The colour is from a pump I use for sucking out oil from car engines. That’s the reason for the colour. Probably some residue left in the pump.

 

It is a tough one as some things become repetitive and rarely the case. It is a catch 22 phenomenon. I wonder if you have noticed that the more times you mention something like old gas, the more times new topic posters will mention having fresh gas for example.

It a simple fix so should always be kept in mind and asked. Some of the replies indicate that the poster does not think it is important, but for these high powered engine, it is very important. And with the extended storage times of sleds and the newer gasolines that don't store well, it becomes even more important to ask.

Was so frustrating to troubleshoot. But it was easier thanks to everyone on this forum. Even though I am a mechanic this was my first time ever working on a sled. So it was quite fun to learn even though it took some time to get it running.

Yes you got a lot of good info here. I come from the world of automobiles and learning these systems have been worthwhile and fun. The engines have differences but also a lot in common... the biggest difference is the belt drive transmissions.