Hard starting / bogging help - Snowmobile Forum: Your #1 Snowmobile Forum

Letters · 01-16-2013, 03:21 PM

Hi everyone. I have a 1997 skidoo mxzx440. 2900 miles. When I first got it (in August) it started and ran great. Started first or second pull every time. Rode it the first couple of times without a problem. The past few times it has been VERY hard to start. The last time I rode it, it would bog at about half throttle but would still run and ride up until half throttle, just slow.

Starting;
- when starting, priming or throttle makes no difference. It doesn't make it easier to start. I pull for approximately 15 minutes to get it to start. The first 8-10 minutes when I pull, it's almost as if I don't have my teather on and I'm just pulling for exercise. Doesn't cough or catch at all. After around 8-10 minutes it starts to cough and spudder for a few seconds then dies. Goes back to sounding like the teather isn't on for about 5 pulls. Then spudders for a second then 5 pulls then spudders then 5 pulls etc. this happens for about 5 minutes. Then spudders for a few more seconds and dies. Then a few more seconds. Finally starts and runs great. Never a problem until I shut it down. If I go to start it 10 minutes later, same procedure. But only about 5 minutes of hassle.

Ran out of gas. Put more in and rode for another 2 miles or so. Started to bog at half-three quarter throttle. Shut it down and left it.

A few days later i started it but would bog and if I didn't feather the throttle it would die. While feathering, 2 or 3 times it would run normal for a second or 2 and take off then go back to bogging the whole time. Shut it down because i couldn't pull anymore.

When I put more fuel in, I just used whatever 2 stroke oil I had in the garage for the premix. Should this be fine or do i need a specific brand of oil. Mixed with premium fuel.

Any ideas in how to fix the hard starting problem? And the bogging issue? I cleaned the carbs 2 rides ago but will do it again.

Sorry for such a long post but I'm considering getting rid of it for this reason. Thank you!!

**smallengineguy** · 01-16-2013, 07:06 PM

Make sure the carbs are clean. Are the chokes adjusted and operating properly? Are the plugs soaking wet when yo first try to start it?

Letters · 01-16-2013, 07:11 PM

Quote:

Originally Posted by smallengineguy

Make sure the carbs are clean. Are the chokes adjusted and operating properly? Are the plugs soaking wet when yo first try to start it?

I was told that there isn't a choke on this model. Only the primer knob. The plugs are dry at the first pull but after that they are very wet. It helps a lot when I remove the plugs and heat the gas off.

**RJ Gleason** · 01-17-2013, 07:33 AM

How many pumps of the primer are you giving it on first attempt to start?
3 should be enough.

Try this, nest time you try to start it, prime it and then pinch off the primer lines and see if it runs better.

edge800ves · 01-17-2013, 12:46 PM

Id do a compression test too, just to be sure. and also make sure your crankcase isn't full of fuel after all that pulling

**smallengineguy** · 01-17-2013, 05:25 PM

Leaky inlet needle/seat on carbs will cause your problem as well.

617Mach1 · 01-18-2013, 08:32 AM

i agree with cleaning carbs again....mine did same thing, i did a quick cleaning and same problem....then i took carbs back off, took all the little pieces out of carb and cleaned EVERYTHING thoroughly, Now my sled runs better then it ever has.

Letters · 03-16-2013, 01:55 PM

Finally got around to pulling the carbs. Cleaned them and same thing still happens. Didn't bother to get it started, pulled for a few and gave up. Plugs get very wet. If I take them out, dry and heat them, the engine coughs once then gets soaked with gas again. If I pull with the plugs out, gas squirts out the top of the engine, and a lot of it.

**RJ Gleason** · 03-16-2013, 03:01 PM

You need to clear that out before it will start again.

richb8612 · 03-17-2013, 01:13 PM

I've been having the same issues...93 formula 600 ran great for the first 2 months this season then during a ride it wouldn't restart..took it to my mechanic and he cleaned the carbs thinking that was the issue..started twice perfectly after getting it back then same issue..my mechanic is totally frustrated..my compression is great..has good spark but plugs get fouled with 2 cycle. Mechanic used compressor to dry cylinders then it starts--runs strong but as soon as it is shut off we need to go through the same sequence again..if you get a good answer I'll pass it on to him

**smallengineguy** · 03-17-2013, 01:45 PM

Like I said above- inlet needles and seats are leaking by. Replace them.

dredlock89 · 03-17-2013, 07:02 PM

i agree the 93 formula 600 the inlet needles are leaking by

TheBearAk · 03-18-2013, 04:20 AM

Another thought would be spark. I would imagine you replaced the spark plugs, but this old of a machine you might also check the spark plug caps. They twist on. Hold the cable and twist the cap counter-clockwise to remove.

Letters · 04-15-2013, 09:05 AM

Quote:

Originally Posted by RJ Gleason

You need to clear that out before it will start again.

How do I go about getting all of it out? Just keep pulling?
Thanks

Letters · 04-15-2013, 09:07 AM

Quote:

Originally Posted by smallengineguy

Like I said above- inlet needles and seats are leaking by. Replace them.

I will order a rebuild kit. Any ideas on where to get them? I did a quick google search and didnt come up with any results.
Thanks

white lightning · 04-15-2013, 10:57 AM

If its not the carbs - check the fuel pump to make sure the diagram isnt cracked. WL

**RJ Gleason** · 04-15-2013, 11:19 AM

To clear flooding, remove plugs and hold throttle wide open and pull till no more mist comes out of the plug holes.
Put in new dry pluga and it should start rigbt up.

Pattyboy7 · 05-05-2013, 07:15 PM

Also, if it's flooded bad enough, on the front of the block there should be a drain plug on the crank case. 1 for each cylinder. I would say take the spark plugs out and the drain plugs out. Pull it over and try again. Definitely sounds like a flooding problem though.

ZRTEETH · 05-08-2013, 12:06 PM

Is the sled "trail converted"? If not it will only run right on high octane race fuel. If it ran too long on regular pump gas than piston and or ring damage may have been done. If it has be trail converted than disregard that. Do a compression check before you do anything else. Please don't be insulted but are you cleaning the carbs the way they are suppose to be? There are alot of small fuel and air circuits that can't be cleaned good unless it is COMPLETELY disassembled. Good spark would be something to consider as well.