supercharged speedster 200 rpm issues and top speed

[VERDUGO135]

Ok. As far as rpm goes port engine starts off running about 500 higher than starboard when throttle levers are even. At about 4500-6000 port engine surges up and down. After 6000rpm they both run smooth and starboard goes about 300rpm higher. They even out close to max rpm which is about 7600rpm for both engines on flat water. Speedo shows 55mph max.

So my question is what should I look for? Going to change spark plugs and add a fuel injector cleaner. I checked to make sure chargers don't spin by hand but will be removing them for closer inspection. Boat is a 2008. Does this mean washers were metal from factory? Thanks in advance.

 

[JoeZ]

Check your wear ring. Might be cavitation

 

[VERDUGO135]

What should I look for on the wear rings?

 

[JoeZ]

A gap between the wear ring and impeller.

 

[VERDUGO135]

Thanks I just googled it. Will do.

 

[VERDUGO135]

Took the boat back out this weekend. I did some maintenance over the week but completely forgot to look at the wear rings. Quick question regarding cavitation. After research I've read the cavitation can be compared to a transmission slipping. If this is the case if my pumps were cavitating wouldn't they still Rev to their max? Yesterday I noted out of the water both engines will Rev past 8k. In the water starboard is 7600 port is 7300ish. Top speed is now down to 50mph but I was running a little heavier this time.

 

[pwgsx]

I got a similar issue but it is worse than yours. I have tried all of the following but no fix yet. Take a look at you might get some ideas of what to check or swap from one engine to the other and see if the issue jumps motors. http://www.seadooforum.com/showthread.php?72366-1-engine-revs-slower-than-the-other

 

[Coastiejoe]

You will easily hit max RPMs. Why? Limited to no resistance. Think about it as tires spinning. If they spin the engine revs up. But if they don't spin, the engine gradually increases in RPMs as the vehicle begins to move. Your boat is the same way except the impeller is the tire and the wear ring is the road. Officially the 08 models have the metal washers. However, we have seen many 08's with the ceramic washers. I believe it is an early build thing. You really have to open it up to determine. The 09 models seem to be good to go.

 

[VERDUGO135]

So just to be clear. Since under load (in the water) the boat does not reach the rpms that it should, I can cross cavitation off the list because if I had a cavitation issue the boat would rev high but not reach speed (spin it's tires). I checked the superchargers for spin but ill be pulling them off to check for ceramic washers. Will be changing plugs, throw in a fuel cleaner. Any other ideas?

 

[pwgsx]

You can swap coil packs from the other engine, fuel injectors, plugs and see if the problem jumps. Also do you have access to a CanDoo system? Your TPS might need to be reset and your throttle cable might need to be adjusted.

 

[VERDUGO135]

Ok heres an update. Although the spark plugs on the boat seemed to have been previously changed I put all new plugs for good measure. As you can see I pulled both chargers and all seems well with them except for some oil leakage. How much oil is normal? I took pictures of the oil. I reinstalled chargers on opposite engines. Also swapped coils. Added 32oz of marvels mystery oil to a full tank. Took the boat out for a test drive. Full tank of gas. Only me in the boat at 180lbs. Engines definitely seem stronger but it could be the light weight. Rpm is around 76-77 for both engines. Top speed of 60 on speedo on glass water. Should I expect more (id hope so especially with only 180lb load)? I don't have a candoo but will be using my mechanics computer to reset tps today. My surge problem is still existent and rpms do not match perfectly. I have linked a video that I took last night. I always kept the throttles even. In the beginning you can see there is a 500rpm difference. Then at around 6k rpm left engine begins to surge up and down. The only way to remedy this is to push throttle past 6k and it calms down.


http://m.youtube.com/watch?v=h1EyeNuyPjE