Page 1 of 3 1 2 3 LastLast
Results 1 to 10 of 28
  1. #1

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22

    First time owner - first time working on any engine (pics)

    I posted a few days ago over here (http://www.greenhulk.net/forums/showthread.php?t=230950) and have received a lot of help - huge thanks to K447. I planned on riding my recently purchased skis until they died on me and then reselling them since I've never worked on an engine in my life, but he's convinced me to try some maintenance to see if I can't extend the life of these.

    I purchased a 93 and 94 SL750. The carbs on the 94 were recently rebuilt and the previous owner made a few more upgrades/modifications. Here are some pictures of what I'm working with - first, the 93.

    The first pic is an overview of the entire engine, and then I took a few other close ups of the different sections. The last pic is the fuel pump (I believe) and it looks like it hasn't been upgraded to the triple outlet - is that correct? I'm still doing my homework on this, but from what I've read so far it seems that this isn't a must have, it just helps get more fuel pumped so I'll go faster? If that's the case, I may hold off on replacing that until I've taken the skis out a few times to see how I like them. You may also notice something different in the fourth pic, above the electrical box. The previous owner installed a kill switch that shuts off all electrical. He said he didn't like that it would take up to a day for everything to shutdown after turning off the machine so he installed this to manually do it, trying to help the battery.

    Click image for larger version. 

Name:	IMG_2923.jpg 
Views:	74 
Size:	90.7 KB 
ID:	357036Click image for larger version. 

Name:	IMG_2924.jpg 
Views:	75 
Size:	131.2 KB 
ID:	357037Click image for larger version. 

Name:	IMG_2925.jpg 
Views:	71 
Size:	115.2 KB 
ID:	357038Click image for larger version. 

Name:	IMG_2926.jpg 
Views:	74 
Size:	96.3 KB 
ID:	357039Click image for larger version. 

Name:	IMG_2927.jpg 
Views:	71 
Size:	104.6 KB 
ID:	357040

    It's not letting me upload the pics of the 94, I'm guessing there's a limit of pics per post so I'll try posting them in a reply.


  2. #2

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22
    Here's pics of the 94

    Click image for larger version. 

Name:	IMG_2918.jpg 
Views:	44 
Size:	61.2 KB 
ID:	357044Click image for larger version. 

Name:	IMG_2919.jpg 
Views:	40 
Size:	121.7 KB 
ID:	357045Click image for larger version. 

Name:	IMG_2920.jpg 
Views:	39 
Size:	97.6 KB 
ID:	357046Click image for larger version. 

Name:	IMG_2921.jpg 
Views:	41 
Size:	92.1 KB 
ID:	357047Click image for larger version. 

Name:	IMG_2929.jpg 
Views:	43 
Size:	101.3 KB 
ID:	357048

    I'd love to hear what you guys think of these - just curious if anything stands out as a red flag? It's probably impossible to tell from pictures, but I thought it's worth asking to see if you notice anything major that I need to have further inspected by a professional - otherwise I'm planning on cleaning the carbs tomorrow and replacing the fuel lines if I can find new ones locally.

  3. #3
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,575
    +1
    1,272
    Quote Originally Posted by BYUFan View Post
    I posted a few days ago over here (http://www.greenhulk.net/forums/showthread.php?t=230950) and have received a lot of help - huge thanks to K447. I planned on riding my recently purchased skis until they died on me and then reselling them since I've never worked on an engine in my life, but he's convinced me to try some maintenance to see if I can't extend the life of these.

    I purchased a 93 and 94 SL750. The carbs on the 94 were recently rebuilt and the previous owner made a few more upgrades/modifications. Here are some pictures of what I'm working with - first, the 93.

    The first pic is an overview of the entire engine, and then I took a few other close ups of the different sections. The last pic is the fuel pump (I believe) and it looks like it hasn't been upgraded to the triple outlet - is that correct? I'm still doing my homework on this, but from what I've read so far it seems that this isn't a must have, it just helps get more fuel pumped so I'll go faster? If that's the case, I may hold off on replacing that until I've taken the skis out a few times to see how I like them.

    You may also notice something different in the fourth pic, above the electrical box. The previous owner installed a kill switch that shuts off all electrical. He said he didn't like that it would take up to a day for everything to shutdown after turning off the machine so he installed this to manually do it, trying to help the battery.

    Click image for larger version. 

Name:	IMG_2923.jpg 
Views:	74 
Size:	90.7 KB 
ID:	357036Click image for larger version. 

Name:	IMG_2924.jpg 
Views:	75 
Size:	131.2 KB 
ID:	357037Click image for larger version. 

Name:	IMG_2925.jpg 
Views:	71 
Size:	115.2 KB 
ID:	357038Click image for larger version. 

Name:	IMG_2926.jpg 
Views:	74 
Size:	96.3 KB 
ID:	357039Click image for larger version. 

Name:	IMG_2927.jpg 
Views:	71 
Size:	104.6 KB 
ID:	357040

    It's not letting me upload the pics of the 94, I'm guessing there's a limit of pics per post so I'll try posting them in a reply.
    The problem with the original fuel pumps is that over time the pump output weakens. The internal flexible membrane stiffens or develops pin hole leaks. While they can be rebuilt the additional cost to upgrade to a new three outlet fuel pump is modest, hence the recommendation to upgrade the fuel pump rather than mess about rebuilding the original.

    The reason the fuel pump is important is that these engines are very sensitive to the ratio of gasoline to air that flows into the engine. It is not about going faster. In fact, if the percentage of gasoline is slightly reduced the engine power can actually increase.

    The problem is that the increased power caused by the reduced portion of gasoline to air creates paradoxically much higher temperatures within the combustion chamber. The temperatures can exceed the melting point of aluminum, literally melting a hole right through the top of the piston. This is known as 'lean burn' and is a very common failure mode with high output 2-stroke engines.

    If you click through recent threads by other new members you will find reports and even photos of burned down pistons. Why threads by new members? Because often the reason they found their way to Greenhulk is that the engine failed and they are now looking for answers as to why it happened and what they must do to correct the situation.

    There is an old saying among 2-stroke engine enthusiasts that they run best right before they go boom. The advice presented in this forum is intended to help people avoid the 'go boom' aspect

    The factory fuel pumps are painted blue, so it seems likely that the fuel pump is original. Has it ever been rebuilt?

    There is another related item to check. The original fuel system had a special control valve known as an auto-cock. These are known to weaken and the result is a constricted fuel flow to the carburetor. A service bulletin recommends removing the auto-cock device entirely and capping off the vacuum hose connection.

    The upgrade to triple outlet fuel pump requires re routing the fuel hoses anyways, so deleting the auto-cock, if it is still present, would happen at the same time.

    The whole idea is to present the carburetor so with a strong and consistent fuel flow and fuel pressure. This allows the carburetor so to properly do their job of delivering the correct mixture of fuel and air into the engine.

    Of course the carburetors must also be internally clean and correctly adjusted.

    How ow do you confirm the carburetors are indeed working properly? The best method is by observing what is known as 'piston wash pattern'. A distinct visual appearance across the top surface of each piston indicates that the fuel mixture is within the required parameters.

    The combustion of fuel and oil creates some carbon deposits on the piston dome. Where the piston is hottest the carbon tends to accumulate. Where the piston surface is less hot the carbon does not accumulate. Peering at the piston top, the presence of small clean metal areas near the edges of the piston indicate a good wash pattern. These clean areas are both fingernail sized. Which fingernail varies with the engine tuning.

    A piston top that is completely black with no clean areas indicates excessive temperatures and is precursor to melting the piston. The photo in this post shows a piston that has begun to fail. There is a crater developing in the center of the piston dome. If the incorrect fuel mixture is not correctly right away that piston will soon fail entirely.

    A completely clean piston top may indicate there is a water leak into the combustion chamber and the water is effectively steam cleaning the piston dome as the engine runs.

    Last edited by K447; 04-25-2015 at 09:28 AM.

  4. +1 by:


  5. #4
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    Location
    near Toronto, Canada
    Posts
    36,575
    +1
    1,272
    Quote Originally Posted by BYUFan View Post
    ... something different in the fourth pic, above the electrical box. The previous owner installed a kill switch that shuts off all electrical.

    He said he didn't like that it would take up to a day for everything to shutdown after turning off the machine so he installed this to manually do it, trying to help the battery...
    I do not have a problem with the idea of having a heavy battery shut off switch, but it is unclear to me why the previous owner thought it would be needed. That said, it is critical that the battery switch and the added wiring be 100% robust. If a switch cable or the switch itself vibrates loose it can shut down the engine suddenly or worst case start and electrical fire with a short circuit. I have seen the extra battery cabling routed close to or even right against the engine where it can abrade and eventually short circuit.

    For some reason these battery switches are often installed into the positive (red) battery cable, which increases the short circuit risk is the cable works loose or shorts to the engine. I rarely see the need for such a switch, but my preferred install is into the black/negative battery cable, not the red/positive cable.

    The electrical system in these machines is rather straightforward. If things are working properly there is no problem with battery drain while sitting.
    Last edited by K447; 04-26-2015 at 09:02 PM.

  6. #5

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22
    Quote Originally Posted by K447 View Post
    Quote Originally Posted by BYUFan View Post
    ... something different in the fourth pic, above the electrical box. The previous owner installed a kill switch that shuts off all electrical.

    He said he didn't like that it would take up to a day for everything to shutdown after turning off the machine so he installed this to manually do it, trying to help the battery...
    I do not have a problem with the idea of having a heavy battery shut off switch, but it is unclear to me why the previous owner thought it would be needed. That said, it is critical that the battery switch and the added wiring be 100% robust. If a switch cable or the switch itself vibrates loose it can shut down the engine suddenly or worst case start and electrical fire with a short circuit. I have seen the extra battery cabling routed close to or even right against the engine where it can abrade and eventually short circuit.

    For some reason these battery switches are often installed into the positive (red) battery cable, which increases the short circuit risk is the cable works loose or shorts to the engine. I rarely see the need for such a switch, but my preferred install is into the black/negative battery cable, not the red/positive cable.

    The electrical system in these machines is rather straightforward. If things are working properly there is no problem with battery drain while sitting.


    Ok, I'm going to replace the fuel pump and all fuel lines this week before taking them out on the water. I'm looking at the Watcon site you referred me to and their fuel pump kit looks pretty straight forward. How long do you think it will take to replace the fuel pump and all fuel lines? Do I need to also replace the filter and all the other parts, or can I just replace the lines? I'm wondering if I need to order from somewhere like this http://pps.partsland.com/Polaris/PWC...1430067246-174 and completely replace everything (screws, washers, connectors, etc.).


    Also, can someone reassure me that this is an easy task. It looks like I can just take out one piece of fuel line at a time and replace it with the new stuff. If I just start at the fuel tank and work my way around, going piece by piece, it seems fairly simple and I probably can't screw it up too bad. The fuel pump looks like I just unscrew the old one (2 screws?) and throw the new triple outlet in it's place with the same two screws?

    One more dumb question. I assume there will be fuel in the lines as I'm taking them out. I can syphon out the tank but is there a way to drain the lines before replacing them?

    I've never worked on anything like this before so it's a little intimidating, but the more I read, the easier it looks. I'm feeling more manly just thinking about working on an engine .
    Last edited by K447; 04-26-2015 at 09:02 PM.

  7. #6

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22
    Quick Update

    I started taking things apart tonight (I was scared out of my mind that I'd ruin the ski), and it wasn't as bad as I though. I don't know the names of everything I'm taking apart, but I believe I took out the air intake, water intake, and removed the cylinder caps. Here's some pics of the pistons and top of the carbs:

    Click image for larger version. 

Name:	IMG_2942.jpg 
Views:	39 
Size:	136.2 KB 
ID:	357178Click image for larger version. 

Name:	IMG_2943.jpg 
Views:	35 
Size:	137.9 KB 
ID:	357179Click image for larger version. 

Name:	IMG_2944.jpg 
Views:	40 
Size:	138.9 KB 
ID:	357180Click image for larger version. 

Name:	IMG_2945.jpg 
Views:	35 
Size:	88.8 KB 
ID:	357181Click image for larger version. 

Name:	IMG_2946.jpg 
Views:	37 
Size:	96.9 KB 
ID:	357182

    I've been reading about wash patterns here, and trying to look at examples on this site and Google images. I'd love for someone to tell me what I'm looking at here - I'm guessing it looks darker than it should be, but it clean on the edges which you mentioned is how it's supposed to look (I think). Also, can you tell anything by these carb pics? Do they look ok? I bought some gumout that I'm going to spray inside, but these were recently rebuilt so they should be good.

    I found the autocock and it looked like it was useless. It had an "in", "out", and "vent" label on it - one line was looping from the "in" to the "out' and nothing was attached to the nosel on the front. I'm gonna call Watcon tomorrow to order the triple outlet pump. I've found fuel lines cheaper from other sites, so I will probably order that from somewhere else. I will be ordering new water intake gaskets to replace the old ones. I think I'm going to order new filters too since I have this apart already - I figure I might as well replace as much as I can while it's open.

    I just realized that this post should probably be in the Projects section and not the open discussion section. Feel free to move this if you need to (some sports forums I visit are very picky about this stuff, I'm not sure how you guys handle it).

  8. #7

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22
    Here's a pic of the other carb

    Click image for larger version. 

Name:	IMG_2947.jpg 
Views:	27 
Size:	92.7 KB 
ID:	357183


    Can I just scrape the carbon off the pistons, maybe a toothbrush and cleaner, to get them clean or do I need to think about replacing them? I'm upgrading the fuel pump, so I'm thinking if I clean the pistons I'll be able to get a better idea of how it's working.


    I appreciate all of the advice I've gotten so far. I'm really hoping to get all the new parts in by this weekend so I can take these out.
    Last edited by BYUFan; 04-26-2015 at 11:49 PM.

  9. #8
    I would leave the carbon on the pistons, you may do more harm than good by loosening it (could get between wall & piston).

    When I installed my triple outlet FP I had to change the way it mounts, as there were 2 more hoses restraining it. I made a bracket that mounts down to the hull rib. Search the site to see how others have done this. Also, call John Zeigler if you get stuck, he was very helpful to me.

  10. #9

    Join Date
    Apr 2015
    Location
    Utah
    Posts
    22
    Quote Originally Posted by JonJet View Post
    I would leave the carbon on the pistons, you may do more harm than good by loosening it (could get between wall & piston).

    When I installed my triple outlet FP I had to change the way it mounts, as there were 2 more hoses restraining it. I made a bracket that mounts down to the hull rib. Search the site to see how others have done this. Also, call John Zeigler if you get stuck, he was very helpful to me.
    Thanks, I won't mess with the pistons. I've read a lot of threads about the carbs and from what I can tell it's going to be a pain in the butt getting in there with a small wrench. I was looking last night but couldn't figure out how to remove them - I think I have an idea now - 6 screws somewhere near the bottom. I'm assuming it'll pop out after I remove those screws. I'm gonna put the new lines on, hit it with some gumout and then put it back in place. My new pump won't be here until Wednesday, but I'm trying to get everything out and ready to go before then.

    Reading about the best place to mount the triple outlet pump and saw lots of different opinions. It looks like it will fit in the same place as the original but some put it lower to help it. I'm going to put it back in the original place, if it fits, and not mess around with mounting it somewhere else. I'm new to all of this so I'm trying to keep it as simple as possible.

    I have new fuel lines coming with the new pump, new gaskets to go under the water cooler (water intake?). I'm feeling more confident about this, hoping it doesn't take too much time to put back together after my new parts arrive.
    Last edited by BYUFan; 04-27-2015 at 06:18 PM.

  11. #10

    Join Date
    Oct 2014
    Location
    Mohave County, AZ
    Posts
    155
    +1
    2
    If you have not done so yet, there is a guy on ebay that sells the FP and lines to go with. Personally, I used the 62-702 (Pentagon) It's A LOT cleaner of a look and cost me $10 more. Big whoop. Came with the lines too, it is the highest flow you can get so if you want to mod the snot outta her I'd say buy one. You can never really have too much fuel going to the carbs. I see you got a 93, I got two, ones dead-ish. Neither came with a fuel restrictor, as noted, get one, it won't hurt. Also with the FP, higher performance Polaris use the 62-702 and Yamaha did too with their 1100. Just food for thought!

Page 1 of 3 1 2 3 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. first time out on raider 701- water gushing from tachometer??
    By shaun23a11en in forum Yamaha Old School Skis
    Replies: 12
    Last Post: 06-07-2012, 06:55 AM
  2. First time out on sea!
    By Phil1987uk in forum Open Discussion
    Replies: 3
    Last Post: 04-15-2011, 12:14 PM
  3. RPM question first time out on green wheel and new prop
    By turbojamie in forum 4-Tec Performance
    Replies: 11
    Last Post: 08-08-2009, 07:10 PM
  4. Replies: 7
    Last Post: 11-17-2007, 10:42 PM
  5. First time out on new Ultra 250X
    By desert dirt diver in forum Kawasaki PWC Performance (4-stroke)
    Replies: 4
    Last Post: 06-02-2007, 01:38 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •