AR192 loss of power

[RookieJetBoater]

Late last year I noticed hesitation on hole shot I was thinking it was a consequence of tuning to 8100RPM. So I would bring up rpm instead of punching full throttle. Now the hesitation is quite bad and in addition the rpms hover instead of staying constant. For instance if I am at 6500rpm they will hover 6000-6500rpm.

Then yesterday boat stopped going over 6000rpm. I don't want to pull the boat out AGAIN. Already went back to dealer this year to replace a wear ring. Its 4hrs to pull ,drive and relaunch plus loss of another week and for sure $$$$.

I am hoping this is a plug or fuel pump issue. Thoughts?

 

[Matts18]

Have you checked the clean out port? Do you have a way to check the rear part of the pump for an obstruction? Is the boat wet slipped?

 

[swatski]

Late last year I noticed hesitation on hole shot I was thinking it was a consequence of tuning to 8100RPM. So I would bring up rpm instead of punching full throttle. Now the hesitation is quite bad and in addition the rpms hover instead of staying constant. For instance if I am at 6500rpm they will hover 6000-6500rpm.

Then yesterday boat stopped going over 6000rpm. I don't want to pull the boat out AGAIN. Already went back to dealer this year to replace a wear ring. Its 4hrs to pull ,drive and relaunch plus loss of another week and for sure $$$$.

I am hoping this is a plug or fuel pump issue. Thoughts?

Supercharger clutch going out?
I know it is supposed to turn only one way, if it spins both way - it's gone.

@SamCF would know more about that of he can chime in.

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[RookieJetBoater]

Thx for responding!

Port is fine. I just had wear ring replaced to fix a vibration. Wear ring had a hole in it!


I think this is a different issue.
It was running 7800rpm and hesitating from 7200-7800 with no change

I slowed down to 6500rpm. It was dancing from 6000-6500. Then I stopped for 5 minutes to no wake mode.. after that it stayed at 6000rpm maximum.

I was thinking it was a fuel issue but now that it stays constant at 6000 max I am thinking electrical and will change spark plugs when I get up on weekend.

Thoughts?

 

[RookieJetBoater]

Would supercharger clutch cause variation in rpm or max out at 6000rpm?

 

[swatski]

CHeck this for some ideas?

https://jetboaters.net/threads/acceleration-issues.21068/#post-358960

https://jetboaters.net/threads/rpms-dropping.17887/#post-372683

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[swatski]

Would supercharger clutch cause variation in rpm or max out at 6000rpm?

I believe so, yes.

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[SamCF]

I would check the fuel filter first. Low fuel pressure will cause hesitation and lower rpm.

 

[RookieJetBoater]

Debug procedure:
1. Check air filter - 5min
2. Check supercharger clutch that can only spin one direction. - 5min
3. Change plugs $100 w tools
4. Check and fuel pump.
5. Give to dealer. It has 5yr warranty

 

[RookieJetBoater]

Here's wear ring hole. Surprising..

 

[SamCF]

Here's wear ring hole. Surprising..

View attachment 96641

That is a cavitation burn. It will happen again if you don't find and repair the source of the cavitation.

 

[swatski]

Here's wear ring hole. Surprising..

View attachment 96641

That's looking like a classic cavitation burn. Wow!
I thought you were having issues with galvanic corrosion but that's looking different.

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[RookieJetBoater]

So, how long would that take to happen? The boat has always cavitated when I turn right
I drove it really hard for 220 hrs until the tune last fall - then another 5-10 after the tune.
I am sure that at least 50-70 of those hours are at WOT.

I don't know the actual tune - it is a custom mapping from Riva. It brought boat from 48 to 51. I don't think it goes over 8100RPM. The only other mod is the Fizzle w/ BOV plus dedicated strainer line.

 

[RookieJetBoater]

The cavitation burn makes sense. I am new to these jet boats and only got interested in tuning because of the heat soak issue

I need to get the loss of RPM issue resolved first. Will go through the checklist and respond back after this weekend.

At least we have the 2 new Sparks up there so I can get my fix

 

[RookieJetBoater]

Pic of the toys on the dock last weekend.

 

[RookieJetBoater]

So, here's the update and it's not great.

The dealer water tested and said the SC clutch was slipping so they replaced it under warranty.
I don't think they lake tested it after the clutch change because it was hesitating on takeoff (5000RPM) or so. The dealership is 20minutes from the water and I think this affects their ability to debug.
This got worse over the weekend until on Sunday it wouldn't go over 6000RPM again for a few seconds. Then it took off and ran fine rest of day.
Yesterday it wouldn't go over 5800 RPM again at all.

SO, I am still fighting 2 issues.
1) There is hot water in the engine compartment. For the life of me I don't know why the dealer didn't find during lake test. There is a clear drip off the engine right where a hose is attached.
2) RPM doesn't go over 6000.

At this point , we have lost 3 weekends with the boat. Short summer up here. 90% of our boating is done by 1st week of September.

Thoughts?

 

[I_squared_r]

Did you try the simple things like air filter and fuel filter? The air filter could be clogged by oil. It doesn't take long to remove the air filter and see if the situation improves. I don't run an air filter anymore. Fuel filter is a little more complicated because it's on the bottom of the fuel pump.

 

[RookieJetBoater]

So, took it back to dealer and clutch is gone again - after 2 hrs!
This time won't be covered under warranty.

Not sure what to do at this point. Dealer told me that the engine has been at WOT 80 of the 220hrs and it's not designed for that.

I understand that 80hrs at WOT without a BOV would wear out a clutch but after 2hrs?

I'm going to remove the tune and keep fingers crossed.

 

[swatski]

Dealer told me that the engine has been at WOT 80 of the 220hrs and it's not designed for that.

With all due respect that is a bunch of horse shit.
Those are continuous duty engines designed to run WOT as long as you want. Are they built that way? They better be!

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[swatski]

I'm going to remove the tune and keep fingers crossed.

Oh I missed that part!
If you are running an tune, all bets are off.
Especially if you exceed factory rev limit.

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