AR192 Low RPM's - sealant?

[SantaFeTrailer]

New to me 2013 AR192. 1,300 feet lake, 45 degree air temp, 54 degree lake temp, only getting about 6,000 RPM and high-20's on the speedometer.

Impeller and wear ring are in good condition, with clearance just about at 30/1000
Throttle control adjusted properly (edit: maybe 1/4" from stop seems OK?)
Supercharger clutch checks out good
Oil is at the top mark, but not over
New plugs on order
edit: checked the air filter, clear of oil

When I removed the impeller and wear ring I noticed that there was no sealant at all. I will use sealant when replacing, but could this be making the difference?

I want to make sure I have my bases covered on what to try, since I am an hour from the lake. However, I have been sitting in my driveway making boat noises, so at least I have that!

Thanks!

edit: for the sake of completeness, we had two of us (say 375 lbs total) and almost nothing else other than pfd's and a fire extinguisher. No idea how old the gas is. Do boat yards usually fill the tank on used boats for you, or has it been sitting since the last time the boat was used? (2013 with 45 hours on it, so it could have been a long time) Maybe I will siphon it all out into my old pickup and fill it with fresh.

 

[tdonoughue]

So, sealant could be an issue with not getting enough speed, but then your symptoms would be different. Typically that would be very high RPM and no speed. Basically, lack of sealant makes gaps that cause disturbances in the water flow, leading to cavitation, leading to loss of power and top end speed. You should still seal everything (and basically do all you can with caulk to make a completely smooth path from the bottom of the boat up to the impellers--including those bolts holding on the grates...). While you have it all in the works, you should definitely do that. Part of your problem may be that--but I don't think that is all of it.

So the first thing to change are the plugs. I see you have them on order. Get those in and see if you get more than 6k RPM. Looks like you checked several of the other common issues. On the throttle, I think it should be to the top. So you can tweak that up, too.

Then we can go from there once you get plugs in.

 

[SantaFeTrailer]

Thank you, that makes sense.

OK, I am on it. I will report back.

So, sealant could be an issue with not getting enough speed, but then your symptoms would be different. Typically that would be very high RPM and no speed. Basically, lack of sealant makes gaps that cause disturbances in the water flow, leading to cavitation, leading to loss of power and top end speed. You should still seal everything (and basically do all you can with caulk to make a completely smooth path from the bottom of the boat up to the impellers--including those bolts holding on the grates...). While you have it all in the works, you should definitely do that. Part of your problem may be that--but I don't think that is all of it.

So the first thing to change are the plugs. I see you have them on order. Get those in and see if you get more than 6k RPM. Looks like you checked several of the other common issues. On the throttle, I think it should be to the top. So you can tweak that up, too.

Then we can go from there once you get plugs in.

 

[SantaFeTrailer]

I got ahold of the dealer and they said that they add "some" gas to test the boat out. So, highly likely that they did not fill it up and this gas is God knows how old. I'll siphon it out and get some clean ethanol-fee in it. It isn't going to crack 40 here for another week at least so any sea trials are on hold.

I have my high altitude prop on order from Impros too.

 

[OrangeTJ]

I'm betting it is the spark plugs.

 

[steve0617]

There is a thought out there that the dipstick full line is too much oil and that it should be no more than half way between the low and full mark.

Don’t know if it’s true but it’s something to consider if you run out of things to try.

 

[SantaFeTrailer]

Hardly a controlled experiment, but got some more data yesterday after new plugs and adjusting throttle position sensor

3600 feet elevation, 60 degree air temp, 50 degree water temp
4 people, plus dog and pretty much full gear - and of course an inverter and Christmas lights
So, lots more weight and 2000+ feet more elevation than the first time.

34 mph (speedo) and, well, I guess I was too distracted and didn't notice/remember the RPMs.

In any event, it is obvious that those two items helped a lot. I have a high altitude impeller on order from Impros, but it will probably be spring until we get out on the water again.

Family all loved the boat, so that was good.

 

[SantaFeTrailer]

They were carboned up, although I wouldn't say extremely

I'm betting it is the spark plugs.

 

[SantaFeTrailer]

I'll change the oil in the spring and get it between the holes

There is a thought out there that the dipstick full line is too much oil and that it should be no more than half way between the low and full mark.

Don’t know if it’s true but it’s something to consider if you run out of things to try.

 

[haknslash]

Keep in mind that anyone in the bow (even just 150 lbs) will drop you a several mph easily on that boat. Not sure where you had your passengers on your last outing report but just letting you know that if anyone is in the bow it can affect performance.

These engines need fairly clean plugs to be optimal so expect to replace them annually even if they don't look dirty. Your high altitude prop should hopefully help you.

With so few of hours on that year boat I'd be weary of the fuel inside it. No telling how long it's been in there. I'd drain it if you can't confirm the last fill-up..

 

[SantaFeTrailer]

Right, forgot to mention that - two people and dog were in the bow. So, I think we are probably doing good. I'll report back in April or so.

Keep in mind that anyone in the bow (even just 150 lbs) will drop you a several mph easily on that boat. Not sure where you had your passengers on your last outing report but just letting you know that if anyone is in the bow it can affect performance.

 

[SantaFeTrailer]

I was hoping just to burn through it yesterday, but we didn't use much. I'll drain it out and run it in my 1985 Toyota, whose primary use lately is as a stale fuel incinerator.

With so few of hours on that year boat I'd be weary of the fuel inside it. Not telling how long it's been in there. I'd drain it if you can't confirm the last fill-up..

 

[SantaFeTrailer]

bow ballast


old plug

 

[tdonoughue]

Old plug: ew. That will cause issues...

 

[SantaFeTrailer]

OK, I got her out for the first time this spring. 6,500 pitch Impros impeller on a 6,400' elevation lake. 60 degree water, 72 degree air. Full tank of fresh premium gas and three souls on board. It was a little windy and choppy, but we were seeing 35 MPH at times. At such an elevation that seems reasonable, so I will mark this problem solved and thank you all for the help. I think we are headed to a 4,400' lake this weekend and we'll see how that goes.