300/440/550 cant get this 550 started.

[maddmatt02]

ok, my brother in law got this thing years ago on ebay and picked it up in phoenix on the way to mexico. it then was never ran(or started so who knows if it ran). it sat there for years and then maybe 3 years ago I brought it back to my house with the intent to get it running, and I looked it over a bit and pressure tested it and I ended up ordering a carb rebuild kit and a head gasket and then put the parts on the shelf and didnt touch the sk again til today.

*I replaced the head gasket
*rebuilt the carb
*took both plugs out, wires on them, grounded them to the head, both have a nice spark
*took the rpm limiter apart and the little needle in there is clean and moves freely
*made sure all fuel lines were clear as well as fuel tap and blew them all out
*blew out the line from the exhaust just after the manifold to the side of the ski
*made sure the check valve in the tank vent line is installed the correct way
*verified that all the fuel lines were ran properly- I believe they are, the 4 lines out of the tank, one is the vent line through the check valve that lets air into the tank but doesnt let any pressure out (I belive thats how it works, either way it says tank with an arrow and the arrow points to the tank), another line that goes to the rpm limiter valve, then from the limiter valve there is a smaller line that goes to the front of the carb, and a larger line goes to the back of the carb. one line from the crankcase goes to the fitting on the side of the fuel pump, and then the other 2 lines from the tank go to the fuel tap and one line returns and goes to the fitting on the front of the fuel pump.
*ran a pressure check and pumped it to 9.5 psi, 3 minutes later it was 9.25 psi still
*ran a compression test (battery kind of weak so I left both plugs out when doing the test so it could crank over a little faster, not sure if it messes up the test or not) got almost 120 in the rear cylinder and I believe only about 105 on the front.


I threw some fresh gas in it and began cranking, no go, it does pop and the engine picks up speed for a second or less but it will never actually run. when I pulled the line off the front of the fuel pump fuel was there, so I know it is at least getting to the carb. the book doesnt have anything in it about the pilot screw so I was forced to just keep guessing. I found on here though that it should be 1-5/16 out so I at least dont have to worry about that any more. thing that troubles me is with each crank it blows some vapor out of the carb, like theres a timing issue, but its a 2 stroke, so no valve timing to be messed up... cant have the spark plug wires wrong since one is too short to reach the front plug so the ignition timing should be good


it will crank a few times, almost start, and then go back to doing nothing but cranking, not even popping any more, then after turning over 7 or 8 times might pop again then go back to just cranking.

the battery is completely crap, but I was jumping it to try and get it started, because Id be pissed if I spent 60+ bucks on a battery and then this thing wont run. so Im waiting til I can get it running for sure to buy the battery.

even being jumped it doesnt crank that fast, maybe like just over one full revolution each second... part of me thinks that just getting it to turn over faster might get it started, but the other part of me thinks that if at times it almost starts its turning over fast enough to at least get it going for one test run...

I am trying to find a how to on setting the pop off right now (havent found it in the book yet), and am going to go through the troubleshooting in the book tomorrow with my DMM to test the cables/relay/etc... and see what I can come up with but was hoping someone might have similar experience as me and can let me know what could be my problem)

 

[maddmatt02]

ok, I made my own pressure tester and will go to home depot tomorrow to get what I need to make it work to test pop of pressure, or make a complete new tester.

I am still confused as to what port from the carb I pressurize? and I need to plug the remaining ports?
from reading though it sounds as though the pop off pressure is more important to keep from running lean at high rpms, not trouble starting, am I right?

 

[cookn]

First off post some pics of the ski so we know what you have got. What carb are you running? If the ski is all stock you should not have to change the jetting. 550s require a good strong battery, and on old skis the starters can crap out and not spin the motor fast enough. It sounds like it wants to start. Are you using the choke? I would also disconnect the rev limiter.

 

[maddmatt02]

as I was typing I even told myself I had to throw that info in there. its a 89 js550. carb is 44mm so I assume its a Bn44. about changing the jetting, I pulled all the fuel screws to replace the o-rings and I didnt count the turns figuring I would use the initial settings to get it running. the last time this thing was messed with was about 5k+ feet lower elevation than I am here. I would assume that I would need to be leaner on the fuel screws up here as well.


I guess the first thing I will look into is the starter, Ill take it apart and make sure any contacts are nice and clean where the brushes ride, etc... and run whatever tests the book has in it.

and when you say remove the rev limiter, would you just replace it with a standard tee and run the lines the same way? or would you just run the return line straight from the carb to the tank and cap off the smaller line from the carb?

 

[maddmatt02]

alright well I took the starter apart, cleaned the ends of the brushes (one looks worn kinda funny so I wanted to get it out and reshape it a little, but my damn impact screwdrivers tip just broke trying o get the endbell off, so I just reached in with a rag and some solvent.) and sanded the comm a little and then greased the end of the armature and put it all back together. put the starter back in, cleaned the battery terminals, and it spins a little better and I really thought I was gonna have it but didnt get to try long. got a slow charger on a shot battery so I dont get to try very long before it really slowed down again, but I didnt have near the charge going to the battery this time that I did last night and it still cranks over as good or better, so once i get a real jump on it it wil probably crank pretty quickly. gotta go meet some people for lunch though so I dont get to play with it until later.

 

[maddmatt02]

alright, I took the plugs out and just cranked it for a while. with the plugs in when it would finally sputter I noticed water coming out of the exhaust, and when I pulled the plugs they were kinda looking like that creamy brown from mixing water and oil. so there must have been some water in the crankcase from when the system wasnt sealed well (I was told that last time they tried to flush it after trying to get it started in salt water down in mexico, water shot out the plug holes) so I just cranked it for a while to just blow everything out, and then blew out the cylinders, blew off the plugs, put i all back together, choked it and it fired up right away. I got the hose to it and the water is staying out of the cylinders this time (YAY). here is a vid. its taken with my phone so you cant really judge it by the sound. the carb needs some fooling with for sure, it hangs at a high idle for a while before it finally drops down to an acceptable RPM (makes me think the low speed or pilot might be lean but I dont know) and then when you go WOT instead of revving it kinda just makes this loud vacuum sound and then revs as you let off...
you can probably tell when that is happening in the video. it will probably be at least a month before I can actually get it to a lake so I just shut it down again and wrapped it up and left the battery on the charger.