99' Summit 500 flooding - Off-Road Forums & Discussion Groups
Go Back   Off-Road Forums & Discussion Groups > Snowmobiles and Sledding > Snowmobile Lounge

Snowmobile Lounge All general discussions relating to Snowmobiles



Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 07-06-2001, 09:36 AM
snownut
Guest
 
Posts: n/a
Default 99\' Summit 500 flooding

I have a 99 Summit 500 that my daughter rides, and it about makes me crazy when she stops on any type of slope. It floods almost immediatly. It is worse if she tips it on its side. I know it has something to do with the HAC, and all the dealers I talk to say it is the "norm" for that machine. There has to be something I can do to help it to some degree, I just haven't figured it out yet. Has anyone had the same issue, and what kind of ideas does anyone have... Keep in mind if she is on the level, there is no problem. It is a brand new machine that was a left over, we bought it in March, and it has maybe 200 miles on it now.

Snownut


Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 07-06-2001, 10:45 AM
retiredpop's Avatar
Enthusiast
 
Join Date: Jul 2000
Location: Calgary,Alberta
Posts: 203
Thanks: 0
Thanked 0 Times in 0 Posts
retiredpop is an unknown quantity at this point
Default Re: 99\' Summit 500 flooding

I've seen this also and like you say the dealers just pass it off as being the normal thing for those machines. However, I don't really buy that it is caused by the HAC. HAC is basically the same system as ACCS that Polaris used and they don't have that problem. I've also heard people blaming the rotary valve intake for the flooding problem too. If you think about it though these systems have nothing to do with shutting off the flow of fuel in to the carb when the float bowl has the proper amount of fuel in it. I think the problem is caused by a poor seal on the fuel inlet needle somehow when the machine is not exactly level or possibly the float level is too high as per the specs from Skidoo. Try setting the float arms so they are not as high as what Skidoo calls for. Also make sure the floats don't bind when you hold the carbs at a different angle than what they would be at when the machine is sitting on the level. I don't know what kind of fuel inlet needle Skidoo uses on these carbs but maybe there is a replacement type you could use that has a viton tip on it if they don't already have one. Or maybe there is an inlet needle you could substitute that has a slightly larger or smaller tip or a different taper angle on it that would seal better under these conditions.

"Sled till you're dead"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #3  
Old 07-06-2001, 10:36 PM
portgrinder
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

ya i havethe same sled. the problem IS with the rotary valves. when the motor is stopped usually one intake port is left open by the rotary design. there is NOTHING you can do for this. any rotax motor of the same style will do this, be it 500 583 or 670. the new series 3 motors have reed valves so they do not do this. you just have to learn to not park on hills or try to keep it running if you roll the machine.

hope this helps, that is the only drawback i have ever had with this sled and love the rest of it

You wear your silver chain but the cross won't stop the lies,you believe in nothing
Kenton Thomas,Portal
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #4  
Old 07-06-2001, 11:59 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

I don't own one of these sleds, but the rotary valve causing the problem doesn't make sense to me. Whether the intake to crankcase is open or closed when the machine is parked will not "cause" flooding. Fuel isn't supposed to enter the carb's venturi unless the flow of air sucks the fuel up.

There must be a source for fuel in order to flood; either too high a float level, a leaking needle & seat, or some other source for the fuel (flow through HAC?, bizare fuel pump problem leaking into the crankcase?, ????).

BTW, I do have a 1978 340RV (one of the earlier rotary valve Bombardiers) and that thing will start fine on almost any angle. I have had problems in the past with needles & seats, but when they're in good shape there's no flooding.

Another point - all piston port engines also typically have an intake port open to the crankcase when not running.

How do those HAC units work? Do they run a lean set of jets and run an enrichment circuit or something? If so, I'd be looking at that extra circuit.

Steve S.

Steve S.
http://home.off-road.com/~ovo/members/sshaw/sshaw.htm
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #5  
Old 07-07-2001, 01:12 AM
portgrinder
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

so your saying that if you tilt a carb that gas wont come outof it?
please send me some of your magic carbs eh, haha. hac is only a couple of hoses and a gas bag that fits into the air box. as pressure changes the bag expands or contracts accordingly, thus creating a vacum or pressure in the hoses and changing carberation. i think the jets in my summit are the same as in my formula 500 and hac makes the carbs leaner.
i have not rode a piston port sled but that is a good point
seriously though all rotary motors of that era do that, cant be helped my friend. all my buddies sleds do the same

You wear your silver chain but the cross won't stop the lies,you believe in nothing
Kenton Thomas,Portal
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #6  
Old 07-07-2001, 11:06 AM
retiredpop's Avatar
Enthusiast
 
Join Date: Jul 2000
Location: Calgary,Alberta
Posts: 203
Thanks: 0
Thanked 0 Times in 0 Posts
retiredpop is an unknown quantity at this point
Default Re: 99\' Summit 500 flooding

Any carb will let fuel run out if it is inverted or turned on its side. But most carbs won't allow fuel to run out when they are at what is considered normal operating angles. I still think the specs are wrong for the float level or inlet needle and seat is poor design. Just because they all do it is no reason to accept that there is nothing you can do about it. I remember the old Tillotson carbs that Skidoo used to use at first (you probably weren't born then. LOL!). They had a vapor lock problem that the dealers said couldn't be fixed. It turned out that all I had to do was enlarge the opening a bit in the return fuel flow fitting on the carb and no more problems. I'm sure there is a fix for this as well if a person wants to spend the time to really look into it. The rotary valve intake thing has nothing to do with it. Take any carb right out of its mounting and fuel still won't run out of any of the venturi fuel openings until you tip it excessively one way or another. If the rotary valve being open or closed controlled the fuel flow then what you are saying is that if you have the carb out you could stop the fuel from flowing out of the fuel passages in the venturi by sealing off the engine side of the carb no matter what angle you hold the carb at. That is truly magic.

"Sled till you're dead"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #7  
Old 07-07-2001, 12:27 PM
portgrinder
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

yes but reed valves are both sealed when the motor is not running so even if there is gas infront of them they wont let it pass through to the crankcase.
you boys can think what you want but i own 2 rotax rotary 500 motors, it is the rotary valves

You wear your silver chain but the cross won't stop the lies,you believe in nothing
Kenton Thomas,Portal
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #8  
Old 07-07-2001, 12:37 PM
retiredpop's Avatar
Enthusiast
 
Join Date: Jul 2000
Location: Calgary,Alberta
Posts: 203
Thanks: 0
Thanked 0 Times in 0 Posts
retiredpop is an unknown quantity at this point
Default Re: 99\' Summit 500 flooding

Hold your reeds up to the light and you will see that they don't seal perfectly so if there is any gas there it would run in anyway. The pressure coming back from the crankcase is what makes a positive seal on a reed and when the engine isn't running there is no pressure to make them seal tight. Besides that when you turn it over you'd let all that gas in that they were holding back anyway and flood it out in any case. You can believe anything you want to though.

"Sled till you're dead"
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #9  
Old 07-08-2001, 07:28 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

I agree with retiredpop, it sounds like a poor needle and seat or too high a float level to me.

My carbs can all handle a pretty good angle before leaking fuel into the venturi. I would guess (without testing) at least 15 or 20 degrees. If your talking about a flooding problem when sitting at 45+ degrees downhill I'd consider that more "normal".

If the needle and seats are good, I'll bet theres a lower float level combined with fatter jets, possibly a different slide cutout, etc. that will greatly improve the situation.

I have seen this problem extensively with Holley carbs on our off-road trucks. Dropping the float level and running richer jetting pretty much fixes them. Rochester carbs also have a bit of a problem when going up steep hills (40+ degrees). The only time I've seen this on my sleds is when the needle and seat is bad (and I've owned at least 15 machines over the past 23 years of sledding, not to mention all my buddies sleds).

Steve S.

Steve S.
http://home.off-road.com/~ovo/members/sshaw/sshaw.htm
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #10  
Old 07-08-2001, 09:16 PM
portgrinder
Guest
 
Posts: n/a
Default Re: 99\' Summit 500 flooding

i would expect more out of a fellow engineer, hehe.

mine only flood when they are dumped over or when past about 45 degrees. these sleds are fine at reasonable angles.

and yes, actually i have my bike apart rite now so i checked my reeds. they do actually hold gas. as for the gassitting just infront of the reeds, when you turned it over the gas would come in and be at least partially atomized by the reeds and the vaccum/spinning of the crank. thus being much more explosive.

if it is carb adjustment, then evey skidoo sled(formula, mxz, summit, skandik) built with the rotary 500, 583, 670 and 670ho has the problem. were talking from 96 to 2001! this is the bulk of what skidoo sold in that time frame. kinda think they would figure it out in that time span? especially when skidoo's 440 race motor was also using rotary valves. thats a helluva number of bad needles and seats right from the factory

ask any dealer my friends. its part of the reason rotax went to reeds, cuz they sure don't make more power

You wear your silver chain but the cross won't stop the lies,you believe in nothing
Kenton Thomas,Portal
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -5. The time now is 06:32 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.2.0
Copyright 1994-2009, VerticalScope Inc. // Off Road forums & discussion groups sitemap
side by side | atv | dirtbike | snowmobile | sandsport | competition | land use | Jeep | Toyota | Ford | GM