900 SL Won't reach top speed

[thetadgt]

Out on the CT River today, I had a plug get fouled that I never got around to changing even though I know it needed to be changed about 3 weeks ago. So I dropped in 3 new plugs, and everything was fine for about 30 minutes of riding. Then, after going through a no wake zone, it would not rev any higher than 5500 rpms. It sounded like it was trying to rev higher at times, but never did till about another 20 mins. Then slowed down, turned around, and it would not go any higher than 5500 again. Put in a second set of new plugs, and still the same results. Any suggestions as to what it could be?

>>>Chris

[thetadgt]

Re: 900 SL Won't reach top speed

After a quick test ride this afternoon after putting in 3 new plugs, it ran fine for maybe 5 minutes, then went back to the same problem. Once back upon shore, it seems that it is running hot. Not killer hot, but to hot to hold your hand on for more than 4 or 5 seconds. I never really noticed it this hot before, so I thought I may have a cooling problem. Once back home, I checked all the hoses and thermometer and all apprear to be fine. No obstructions in the hoses, and the thermometer fuctions as it should. Could this be a fuel delivery issue in that it is not getting enough fuel once cruising? The plugs are not dry, but are not to the point of fouling out. They look normal to me. Any suggestions?

>>>Chris

[hunters]

Re: 900 SL Won't reach top speed

New plugs take a few hours to show actual performance.
It sound to me like you are running too rich and fouling the
plugs.
Someone please correct me if I am wrong.

[javiert99]

Re: 900 SL Won't reach top speed

Be very careful running the ski at this point.

Read this:

http://server1.sbtontheweb.com/forum...ad.php?t=15924


Well, I lost compression on my 1st cylinder this afternoon, I believe I may have a hole in the piston. Might be running incredibly lean.

[thetadgt]

Re: 900 SL Won't reach top speed

Finally got around to taking the carbs out for a rebuild. While I have them off, I am going to install the oil pump block off kit. The question I have, is to I have to adjust the carbs to compensate for the premix, or is the stock setting ok?

>>>Chris

[WATERCRAFTSERVICES]

Re: 900 SL Won't reach top speed

Stock Settings. 40:1 Ratio On Mix.

[thetadgt]

Re: 900 SL Won't reach top speed

Thanks a lot for the quick response!

[thetadgt]

Re: 900 SL Won't reach top speed

Ok, rebuilt the carbs and switched to premix, but still have the same problem. At WOT, the ski will not rev past 5700. Reading through javiert99 post on a similar problem, I decided to take a quick look at the top end to see if I maybe toasted one of my pistons but all was well. While out on the test run, I did notice if you feather the throttle to some degree around 2/3 throttle, it will rev up to about 6250 or so, but anymore throttle, it will die back down to 5700. Idle is seems to be good (at least I think it is), about 2800 on the flush kit and 1300 on the water. Spark is good, I have new plugs in, and I cut the wire back about 1/4 in the boots too. Any other things I can check?

[modking]

Re: 900 SL Won't reach top speed

Check the trigger coil on the stator. Most likely it is going out. You still have spark but the timing will be off if the trigger is going. There are specs to check it with. If you need them I will have to look them up for you

[javiert99]

Re: 900 SL Won't reach top speed

modking.. after I get my motor rebuilt I'll be looking into the problem that I've got going on, so if you could get those specs I'd appreciate it :)

[thetadgt]

Re: 900 SL Won't reach top speed

Ok, I'll check that this weekend if the rain clears. If you can look up the specs, that would be great. Thanks in advance.

>>>Chris

[thetadgt]

Re: 900 SL Won't reach top speed

Besides checking the trigger coil on the stator, one of my friends said to check out the reeds. Is it normal for the reeds not to function properly after 146 hours ? I was planning on getting a set of Boyesen reeds over the winter, but I may sleed up my purchase if they may be a problem also. The question I have about them though, is which ones would be the best. The question I have, is which ones should I go with as the price difference is that much between the power reeds, pro series reeds and the racing pro series reeds is not that much? Currently the ski is stock, but I do plan on upgrading the flame arrestors as well over the winter.

>>>Chris

P.S. How exaclty do I check the trigger coil??

[modking]

Re: 900 SL Won't reach top speed

Reeds typically only effect the low end performance of the engine. It is a good practice to check the reeds to make sure they are not cracked or chipped on the corners. Take a careful look at these areas. Also look at where the reed petals hit the reed cage assembly to make sure that they are sealing there. Hold them up to the light to see if they are sealing. The reeds could have lost their tension, but without checking them you will not know. We have found the stock reeds to be very good period. If the reeds are bad them we sell an aftermarket reed that is less exspensive then Boyseen and works just as well. The complete set of replacement reed petals is $69.95. Dont expect reeds to make a big performance gain. They will effect low end and low midrange performance only.

[Alwet]

Re: 900 SL Won't reach top speed

http://www.pwctoday.com/viewtopic.ph...=properly+test

Here is a link explaining the Trigger coil test.

[Jamie in NY]

Re: 900 SL Won't reach top speed

I was struggling with something very similar on my slt780. I had been trying to adjust the carb low/high speed jets for a while. I thought I had it leaned out pretty far but the plugs still showed rich. Anyway, I was leaving the dock for another test run and the ski took off like a SHOT, like the good old days. I had forgotten to turn on the fuel knob, and the while the ski was running out of gas it ran lean for a split second, which is when it ran great. I ran out of summer before I got her dialed in, but I am convinced I was running rich, which prevented the ski from running fast. Be careful...always a danger of burning out the engine while palying on the lean side.