Poor performance?

[Gizzygone]

Looking to diagnose some poor performance today:

Boat Idles fine and is good to 1/4 throttle:.... but past 1/4 throttle response is very lacking. In fact: you could hear the motor surging at points.

I DID just do an oil change and replaced the plugs. But it's also full of last season's gas (used StaBil marine prior to storing).

Could it be the plugs? Too much oil? Bad gas? Or something more sinister: like the supercharger clutch?

 

[anthonymsaad]

Sorry to hear that.

What boat model do you have? Last season's fuel shouldn't be an issue with stabilizer added. Can you explain further about the surging issue and throttle response? If the clutch on the supercharger does start slipping, you will notice some surging issues. This would be due to the supercharger being unable to provide consist boost. Do you remember when the supercharger was last rebuilt?

 

[CSager]

Did you check the gap on the plugs? Check the oil level they don't like to be full keep it at 3/4 on the stick put some seafoam in the fuel tank if you did get some water in there its magic for clearing it out and cleaning your fuel system too!

 

[Gizzygone]

Sorry:

It's a 2009 Challenger 180 SE with the 255hp supercharged motor.

Supercharger has yet to be rebuilt.

I'll pull some more oil out of it: I'm wondering if I don't have the boat sitting at the right angle when I'm measuring? Should the trailer be level (the manual says keep the bumper rail level which is tough to do seeing as it curves over the length of the boat!).

I did check the plugs to be at .30 gap

 

[CSager]

You should be good close is enough you just don't want to be at the full line or above how many hours on the motor?

 

[Gizzygone]

I believe she's sitting at about 120 hours.

 

[kernal]

Are you able to get to 8000 rpm's? or does it rev up to 6K and then start surging?

 

[Gizzygone]

It doesn't get to 8000. I think I noticed surging around 5500rpm

 

[kernal]

That's about where the supercharger starts making more boost then the engine makes vacuum. If the SC has not been rebuilt I'd prolly start there.

 

[JPass]

Sorry:

I'm wondering if I don't have the boat sitting at the right angle when I'm measuring? Should the trailer be level (the manual says keep the bumper rail level which is tough to do seeing as it curves over the length of the boat!).

I'd either run a level across the top of the motor or on the swim platform to confirm the boat is level when checking fluids.

 

[go_panthers]

What kind of oil did you use?