Acceleration Issues

[Alex Renaud]

Looking for ideas on what’s going on with my boat, I’m stumped.

A little background. I have a 2014 SX192 that I purchased used last year. The boat only had around 14 hours on it and I bought it from the shop that was servicing it. Currently the boat has around 55 hours.

The first half of the summer the boat ran perfectly, turn the key and go. Around the middle of the summer I had something peculiar happen. We launched the boat and idled out away from the ramp as we always do. Once ready I pushed the throttle down. The boat reached about 6k rpm and only about 10 to 15 mph. Not sure what was going on I pulled back to neutral position and tried again. Worked perfectly the second time reaching full rpm and full speed. Didn’t think anything else about it and it ran great the rest of the day.

The next day we had the exact same issue except this time I had to pull back to neutral a couple times before it would run correctly. By the end of the summer the issue had progressively gotten worse. Each time taking longer than the last. Once it was running fine for the day it seemed to run fine the rest of the day with starting and stopping throughout a trip. The last time we had the boat out last year it took almost an hour of idling around before it would run correctly.

I recently had the boat serviced hoping maybe I had a fouled plug or the shop would find something obvious. I was able to get it on the river last week with my fingers crossed only to see it’s still doing it.

What’s throwing me for a loop is that it’s not a problem that comes and goes. Once it started last year it’s happened every time sense and progressively worse than the last time. Any suggestions are welcome, PLEASE HELP, summer if right around the corner.

Items I’ve already looked at:
Wear Ring appears to be in great shape
New plugs
Throttle cable looks to be adjusted correctly
Cooling ports appear to be flowing properly
The inspection port locks in position fully

Thanks,

Alex

 

[SamCF]

Possibly a slipping supercharger clutch. If you are running any oil other than the specified Yamalube, it could be causing clutch slip. It also might just be the clutch itself going out.

Pull the air intake hose from the front of the supercharger. Spin the charger wheel. If it turns freely both ways it is bad.

Even if it doesn't spin both ways, it could still be on the way out.

If using other oil, change back to Yamalube and see if it improves.

 

[Alex Renaud]

Thanks, I hadn't thought about the clutch. It'll be the first thing on my list to check tonight. I'm not sure what oil was used during service. I'll have to find out.

 

[d_coyne1984]

Does it sound like it is cavitating? I am wondering if the sealant around the pump intake failing could cause this to occur.

 

[Alex Renaud]

Nope no cavitating. When the boat is running it sound like its running great. After reading SamCF's response I'm wondering if the supercharger clutch is just low on oil. This would make sense as to why it's getting worse and worse if i'm losing oil somehow. I'm also wondering if that's why I'm not getting full rpm's or speed, because the supercharger isn't engaging.

 

[haknslash]

Might be worth pulling your pump and seeing if there is any sealant.

 

[Alex Renaud]

Well I was hoping it was the clutch so I could at least know the issue finally. Unfortunately I pulled the intake hose and it only spins one direction. Back to square one. Any other ideas?

 

[haknslash]

Well I was hoping it was the clutch so I could at least know the issue finally. Unfortunately I pulled the intake hose and it only spins one direction. Back to square one. Any other ideas?

Yes, see @d_coyne1984 and my comments above. I would also inspect the intake grate and sealant inside the pump tunnel. I wouldn't say unfortunately when talking about the SC impeller only spinning one direction. That's a GOOD thing at this point but like mentioned isn't a definitive if your clutch is on its way out. However with the amount of performance loss you're talking about you would most certainly have play if that's the case I would imagine. I don't think your clutch is gone for that reason. If it is though I'd upgrade to the stronger SVHO clutch kit. You would also need a new front gasket and the clutch tool.

 

[SamCF]

Another possibility is a clogged fuel filter. Mine started acting sluggish and bogged on initial acceleration. Turned out to be trash on the filter.

The filter is on the bottom of the fuel pump housing.

 

[Alex Renaud]

Hopefully I can do some more investigation tomorrow. I did inspect the intake grate area and wear ring very close back when I thought it could be the wear ring. I don’t recall any sealant missing but I’ll look again just to be safe. I’ll look for the fuel filter tomorrow and hopefully get it replaced. It’s not sluggish per say just no power. The clutch doesn’t really have any play to it. Turns good one way and locks the other.

Here’s a pic of the tunnel. I can see most of th sealant.

 

[swatski]

Does your cleanout plug sit tight, with no or minimal water blow-through?

--

 

[Alex Renaud]

Yes, it seems to lock in just fine.

 

[swatski]

I could be wrong but if you can get the engine to rev up to 7,500 RPM or so at WOT while not generating much thrust, which then magically re-appears - this to me indicates a major ventilation/cavitation issue that is "erratic", like something is loose and then it locks in place.
Alternatively, if you do you not get the engine to spin at or near max RPM (of 7,500 or so) at WOT (while the boat is not running well) - that would indicate one of the issues @SamCF mentioned. No?

--

 

[Alex Renaud]

When getting 7500 rpm the boat runs fine with zero hesitation. It's when I first crank the boat for the day it will only reach around 6000 rpm and only about 10 to 15 mph. I really thought we were on to something with the supercharger clutch until I checked it last night. Someone at work mentioned disconnecting the battery to see if it would reset the computer. I'm not even sure if that's something to consider or not. I was thinking the kill switch did that already.

 

[seventyeight]

Is it possible the bucket is not opening completely (sometimes) ? I noticed you checked operation of the throttle cable, but no mention of the gate linkage/ operation.

 

[Alex Renaud]

I haven't looked into the bucket linkage yet. Question, regardless if the bucket is opening all the way I wouldn't think it should affect the rpm's?

 

[swatski]

When getting 7500 rpm the boat runs fine with zero hesitation. It's when I first crank the boat for the day it will only reach around 6000 rpm and only about 10 to 15 mph. I really thought we were on to something with the supercharger clutch until I checked it last night. Someone at work mentioned disconnecting the battery to see if it would reset the computer. I'm not even sure if that's something to consider or not. I was thinking the kill switch did that already.

OK, then it’s not the pump, or cleanout plugs, or the buckets. None of that is electronically controlled in a 192.
Has got to be what @SamCF said, the supercharger sounds most probable as that fits the symptoms exactly. Frankly I would focus on that.

Or fuel, like he said.

—

 

[Alex Renaud]

That's kinda what I'm thinking as well. I guess it's time to pull the supercharger and get a closer look.

Will I need to drain the oil just to pull the supercharger? I know I will if I go any deeper.

 

[why_fly_high]

Before you do that did you say if you have pulled the fuel filter yet? I've had 3 PWC's do exactly what you describe and every one of them were fixed with a new fuel filter.

 

[Alex Renaud]

I haven’t yet and I don’t believe it was replaced during service either. I’m hoping to pull it this evening. Is this a filter I can get from a local parts store or does it need to be Yamaha?