Boat bogs down at full throttle

[mgrey]

I have a 2003 Sportster LE with a 951 engine and I have a little problem with the boat not running at full throttle, it slows down a little bit. I've cleaned the RAVE valves, they were dirty, and put new plugs in. I've replaced the plugs 3 times this year as they appear to be very fouled and after awhile (5 hours) I have poor performance, with new plugs it runs great but not at full throttle. It looks to me like the carbs are running too rich, based on the condition of the plugs when I remove them. I notice at times it appears as though I'm getting a lot of smoke at idle also.

I was at a sea-doo dealership last week and the mechanic I spoke with said that the carbs should not need adjusting they never go out of adjustment... I hand that hard to believe, I'm also the 3rd owner of this boat, bo I'm not sure what was done be previous owners...The mechanic said I most likely need a top end rebuild. I find this hard to believe that the boat only has 70 hours on it and this mechanic said it sounds like a re-build, he said that he has done over 500+ rebuilds on the 951's him self. I checked my compression in both cylinders and they both read 145 PSI so I find it hard to believe that this could be the case.

I have a service manual for the boat but it is very difficult to get at the carb adjustments with the exhaust pipe right on-top. Do I need to remove the air intake box and the vents that attack to that to get at the adjustments?

Also the boat is running at about 1050 RPM's at idle and it should be 1400 RPM's I know there is 1 idle speed adjustment for both carbs, should this be adjusted also?

From all I have read about the carb's and the adjustments this appears to be my issue, but just wanted a second opinion and your thought about needing a top end re-build?

Thanks for your help on this.

 

[kustomkarl]

If you have 145 psi, you don't need a top end rebuild. Ideally 150 psi is the goal.
Yes remove the carb air box to get to the adjustments. The Low Speed adjustment should be set at 1 1/2 turns out. It has a pin through the adjuster. The High Speed adjustment has a plastic cap on it. It should be adjusted to "0". The plastic cap allows it to only be adjusted 1/4 turn but it should be set to "0".
The jet boat should idle at 3000 rpm's out of the water and 1500 rpm's in the water under load. Use the idle adjustment screw, to adjust both carbs. Do not use the low speed screws to adjust the idle. Be sure both carbs are adjusted in sync and the oil injector cable is in sync with the carbs too.

I hope this helps.

Karl

 

[mgrey]

That's what I thought...thanks for your help...

I do have another question though...how do I go about setting the Oil injection cable to be in sync with the carbs?

 

[kustomkarl]

Where the throttle cable connects to the injector check that the when the throttle cable starts to move so does the oil injector cable. The oil pump has a small line mark on the cable disc and lines up with the pump mark. Both cables should move at the same time, and return at the same time to be in sync.

Karl