Engine problem?

[Donnieboy59]

I have a 2012 Sea doo Challenger 180 boat and I'm lost what to do. We were water skiing about 2 months ago and while I was in the water trying to get ski's on my brother was circling me and waiting till I was ready. The rope was pulled into the propeller and shaft so bad it stopped the engine dead. Apon inspection I found it damaged the prop and shaft. I replaced everything from the shaft to the pump and propeller. Now the engine will not rev up or go over four grand on the tach. It acts like it has a governor on it. any help or suggestions would be greatly appreciated. I've been a mechanic for 40 years but this has me stumped. I've never worked on a marine engine like this.

 

[ODavis]

Yeah these things can throw you for a loop.

Couple of questions:
What exact engine do you have?
Can you turn the prop shaft by hand? Could be binding and causing reduced RPM.
If an SCIC check the SC for free wheel. Could have been damaged with the sudden stop (long shot) but worth to check.

Good luck, post back with any info.

 

[Donnieboy59]

It's the 4-tech super charged engine. The drive shaft comes right off the engine's crank and I cannot turn it by hand. I take it when you say SC your talking about the super charger but what is SCIC?

 

[ODavis]

SCIC is Super Charged Inter Cooled.

To check if the SC is free wheeling, remove the intake hose and use your hand and see if the blade spins at all. If good you won't be able to spin by hand, but as mentioned, that is a long shot and probably not the issue. But worth checking.

It may be possible that you put a larger impeller on then what it calls for and it is binding. Verify what you put on, I think you may have a 159mm pump but not sure. They vary only by a few mm's and you could feasibly get a larger impeller into a smaller pump housing and it may be binding. Hard to diagnose from a forum. This is really a feel sort of thing.

 

[Donnieboy59]

Already checked that when I replaced everything. It's all stock with factory replacements. I have the recommended gap. I'm thinking it may be in the supercharger.

 

[ODavis]

So if you remove the intake hose, you can see the blades and you should not be able to spin the blades by hand. Your year shouldn't have that issue, but if the engine suddenly stopped while at high RPM that could be an issue. It comes off fairly easy, three bolts that are not easy to get too but still not bad.

 

[Donnieboy59]

I would have thought you could spin the blades. Seems it just a turbo charger to me like on cars and hot rods and the blades spin freely. I thought air velocity would control the spin. I can't spin the blades on mine.

 

[ODavis]

I would have thought you could spin the blades. Seems it just a turbo charger to me like on cars and hot rods and the blades spin freely. I thought air velocity would control the spin. I can't spin the blades on mine.

No not at all. While it is like a turbo for sure, the blades are mechanically turned by the PTO/Cam gear(s). There are washers that act like a clutch so when the turbo is abruptly slowed or stopped it doesn't snap the shaft.

 

[Donnieboy59]

Well I suppose my next step is pulling the supercharger and see what I got.

 

[ODavis]

Well I suppose my next step is pulling the supercharger and see what I got.

You can just pull the inlet hose and see if it spins or not. There is only a clamp holding the hose on and then that exposes the blades. Try and spin the blades with you fingers. Nothing about the blades should move, it's a 5 min check.

Pulling the SC is a bit of a PITA, only 3 bolts but the top bolt is tough to get too and the exhaust v-clamp must be removed and the exhaust slide back. Still only a 30 min job, but the chance of the shaft snapping is remote. Just a piece of the puzzle to check.

 

[BGS]

I know it is does not fit the story but the first thing you do on these engines is replace the spark plugs. Cheap at auto supply & easy.