08-21-2011, 05:24 PM #1
2000 Polaris SLH - No Power, Hard to Start, Struggles to REV
So I have a 2000 SLH with the 700 twin domestic engine. I recently rebuilt the carbs and had replaced the fuel lines last summer. The ski was running very well the last time I had it out. I took it out yesterday and the ski started hard and once running idled around 800rpm in the water. When I would hit the throttle the ski just bogged down and if I held the throttle open I wouldn't get over around 3k rpm. At one point, it took off hard and I let off after a few seconds of the ski accelerating (didn't want to risk blowing anything) and in the short time going back to the launch it had no power like before.
I just pulled and checked the plugs and both are wet. If I start the ski out of water it will rev up ok but has a misfire and runs rough. I started to run though some of the ignition tests (for the updated ignition that I have) and everything seems to be in spec from what I can tell. The only discrepancy I saw was that the in the wiring diagram it says "EXCITER COlL # I : BLK TO PUR 5.5 OHMS" and I am reading approximately 7 OHMS after correcting for the 0.8 OHMS from just the resistance of the leads of my multimeter. I assume that this is probably ok but wanted to get a second opinion. I also replaced the plugs with another set of the BPR8ES NGK's gapped to .028".
Anyone have any suggestions as to what would be good to look at next? The compression is ~120 psi in each cylinder and fuel pressure between carbs at idle (out of water) is a touch over 2psi.
08-23-2011, 05:54 PM #2
From what I can tell the ignition system is still fine and I just rebuilt the carbs so I don't think there is an issue there but the wet plugs and struggling to rev gives me the indication (I think) that I either have a weak spark output and am not burning off the mixture or for some reason I'm getting too much fuel.
08-23-2011, 07:57 PM #3
Are both cylinders running? You can run the ski for 10 seconds then feel them with your hand, they should feel the same, if one is cold you have fuel issue.
08-26-2011, 08:44 AM #4
I beleive so but I will double check that. Haven't had a chance to work on it but will when I get out of work tonight.
On a side note does anyone know what my sustained wide open throttle RPM should be at or around?
08-26-2011, 06:35 PM #5
Yes, both cylinders are warm to the touch after running for a few seconds. I don't have an accurate way to measure it but they feel the same as far as temperature goes.
I did pull the flame arrestor off and the ski does seem to rev better. I'm pretty sure I have a fuel issue somewhere and that is running too rich but I'm quite sure yet...
08-27-2011, 02:46 PM #6
Another update, started going through the fuel system this morning but have/had a wedding to attend this afternoon. I decided to start checking everything and decided to fix a couple bugs along the way.
First, I pulled the fuel sending unit out and determined that the fuse was blown on the circuit board so I replaced the fuse with a hard wire and then added a fuse to the connection in the electrical box. I'll post a link later on so if someone sees this post in a search they will find what they need. It took me a while to find it and its bookmarked on my other computer.
EDIT, Link to troubleshooting/fixing fuel sender unit issues
Second, I pulled the pressure check valves coming out of the tank to make sure they were working and found that the check valve that allows gases to exit the hull through the breather to be stuck. I'll have to look and see where I can get a replacement.
Hopefully tomorrow I'll be able to finish running through the fuel system and make sure everything is in working order. I'm hoping to find something in the carbs or something obvious. Wish me luck!
Last edited by ThrottleOut; 08-29-2011 at 07:07 PM.
09-03-2011, 07:08 AM #7
Well got some time to finish going through the fuel system and found my issue. What happened was when I rebuilt the carbs initially I used all of the parts from the SBT carb kits which I thought at the time were genuine Keihin. When I had hesitation issues, I reinstalled the original metering spring which fixed that. Now, the first time I installed the metering block with the new o-rings on the fuel filter they were difficult to press in even when oiled up. So, I used the screws that hold the outer cover and metering block in to draw that assembly together and then tightened the one screw that holds the metering block in. The second time when i swapped out the spring, it looked like I was able to hold them enough by hand to not need to draw the metering block in. My guess is that when I tightened everything down it took just enough pressure off these screws to allow them to vibrate loose.
So in case anyone comes across this thread while searching here are a few tips for rebuilding and working on Keihin CDK II carbs:
- SBT Carb kits are NOT OEM Keihin. I assumed that being a reputable seller they would be and they unfortunately are not.
- When reinstalling the metering block, use the 4 screws that hold the outer cover on to draw it in so you can install the screw that holds the metering block. Also use a drop of blue, medium strength loctite to make sure this screw does not back out. If you do this, you need to clear the threads well otherwise that loctite will not do anything
- Make sure you set your control arm is 'adjusted' properly to be within the .060" spec per the Polaris manual.
General SLH tip:
- If your fuel gauge always reads empty odds are the in-tank fuse has gone bad. If the fuel gauge always reads low (or oil gauge in this case) the float is gas-logged and needs to be replaced. See the link in my previous post.
Hopefully this information can help someone in the future.
On a side note, the SLH hit a max of 54.5 mph at 6770 rpm per the MFD's peak function. This was in somewhat choppy water too so i'm sure on glass it should hit better speeds but I think my max rpm is really good. Maybe now that its running I can start playing with some mods...
09-03-2011, 10:27 AM #8
Nice trouble shooting!
I guess the moral is 'always check and double check your work'
09-03-2011, 07:24 PM #9
Yes it definitely is. Got a few hours in of riding this morning and checked piston wash and it looks very good, just a touch on the rich side.
I also have a new top speed of 58.0mph according to the MFD. My buddy took it out for a quick run while I was backing in the trailer and hit a max of 58.8mph at IIRC 6750 rpm via the 'max' mode on the MFD. I think on glass I *might* be able to see 60mph on the MFD. Cool!
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