Boat slow tonight

[mraz72]

Just got off the phone with my dealer, he is leaning heavily on the fact that I wet slip. At the sandbar this weekend, I will try to scrape away some sludge and see if that really makes a 10 mph difference.

I might get the boat acid washed in July to see....

 

[Speedling]

Remember that any buildup inside the pump will have a multiplied effect.

 

[Chillypilot]

Just pull the boat pull out and clean the hull. A couple of hours work and a little elbow grease and you'll have eliminated one possible cause. I wet slip and clean the hull every six weeks or so.

 

[mraz72]

acid wash or just clean with soap and water?

 

[txav8r]

If you haven't sucked anything up and don't run shallow, nor do you beach and try to power off the beach, my guess is that your impellers are fine. If you do power out of sandy areas under 3' deep, you may have sandblasted them. But you would have to have done this a bunch to do much damage to them that would drop top end. Sandblasting isn't going to reduce top rpm unless something is stuck in the pumps or your impeller is severely damaged, but you would notice the cavitation it causes well before a top end rpm problem. Speed is a result of all other factors, and a wet slipped boat screams hull and pump contamination. I would just pull it out and give it the once over. You can check the pump pretty easy with a flashlight, a mechanics telescoping mirror, and getting under the boat and behind it, looking into the pump and impeller. Any damage will be noticeable, as will results of sandblasting. After that, clean it up and see how she does. On a side note but very important...know exactly what your dealer does to the boat. Don't settle for letting them winterize and getting it out of storage mode, you will never know what was done and what could be a possible problem. Members have found oil overfilled, air filters contaminated, work never done, and more...all from dealer service. There are excellent trustworthy dealers out there and I don't intend to slander them, but all dealers are not created equal. Even if I let my very excellent Phil Dill Boats maintain my boat, I would know exactly what, and how, they did whatever they did to my boat. Trust me, you want to know. And I have had issues with fuel before myself on previous boats I owned...that is why I treat every single tank of fuel with a storage ratio of Marine Grade Stabil, that way, when the unknown happens, and it will...my fuel is always treated for long term storage.

 

[Julian]

Just got off the phone with my dealer, he is leaning heavily on the fact that I wet slip. At the sandbar this weekend, I will try to scrape away some sludge and see if that really makes a 10 mph difference.

I might get the boat acid washed in July to see....

If your boat has growth on the hull I GUARANTEE that will take 10-15 MPH off your top speed!!!! If you clean that hull well and have no cavitation and top speed ain't back....I'll send you a Jetboaters.net shirt!

 

[mraz72]

If your boat has growth on the hull I GUARANTEE that will take 10-15 MPH off your top speed!!!! If you clean that hull well and have no cavitation and top speed ain't back....I'll send you a Jetboaters.net shirt!

LOL, now I'm going to lie just to get the freebies

@txav8r - good info, I will be more diligent in finding out what they do and checking the work. I believe i have a reputable dealer (probably everyone does), they have been there for over 30 years and seem to pride themselves on reputation. I've never heard a bad word about them.

I guess its the hull. I am going to get the boat our, and go over it with soap and water. I am not going to acid wash it, I would pay the dealer for that. If I see an increase in speed after cleaning it, we can chalk it up to that.

Only 1.5 months in the water and lost 10-15 MPH, damn!

 

[Julian]

LOL, now I'm going to lie just to get the freebies

@txav8r - good info, I will be more diligent in finding out what they do and checking the work. I believe i have a reputable dealer (probably everyone does), they have been there for over 30 years and seem to pride themselves on reputation. I've never heard a bad word about them.

I guess its the hull. I am going to get the boat our, and go over it with soap and water. I am not going to acid wash it, I would pay the dealer for that. If I see an increase in speed after cleaning it, we can chalk it up to that.

Only 1.5 months in the water and lost 10-15 MPH, damn!

This is precisely why I bought an airdock lift! I hated losing the top end and have to drive at 10-30% higher RPMs for a given speed. A simple wash will help, but you'll find using one of the acidic products will make it so much easier!! Check the FAQ on cleaning...there are some links there if I recall correctly.... and some creative products people use that are cheaper than products like Starbright hull cleaner

 

[Tom V]

Are you sure its not heat soaking because the air temps are getting hotter, look at the 192 thread.

 

[txav8r]

I have spent the better amount of my lifetime flying airplanes. 99% of that time, 38 years, has been professionally. When I read the performance threads, I often cringe, as everyone isn't aware of all the factors that affect performance. On a non turbocharged engine, everything affects it. But some things more than others. As a generalization, increase in elevation, or temperature, or atmospheric pressure, will decrease performance. This decrease is not apparent with subtitle changes. But when reading on a forum such as Jetboaters.net, and our varied memberships lakes and ocean locations, it isn't subtitle. A guy boating in Utah or Tahoe, faces a much grater loss of performance than a hot day verses a cold day at sea level. A MUCH greater loss. It is a routine loss for the high altitude boater (or flyer). But the 192 is an engine capable of maintaining sea level performance MUCH higher in elevation than sea level. I have not run the charts, but there isn't much loss due to temperature swings on a turbo or super charged engine. For the most part, cold dense air will produce more HP than Hot thin air. But the turbo makes up for the less dense air due to elevation change. I have said many times, the 192 isn't for everyone, and it is often misunderstood by the masses, as to what its capability is, over its counterpart the 190.

Finding out what changed before maintenance to now is important. Finding out if something isn't normal also. Some have had an in compartment exhaust leak, others a dirty hull, others lost power due to old fuel, and still others had an air loss due to dirty air filter. Finding out if you have an air filter problem is easy, take them out and see if it runs normal again. Same with an exhaust leak, open the engine hatch and run it. If the power comes back, you are on to something. But the difference on a 192 on a 50 degree day vs a 100 degree day is not a severe change in performance. On a 190, it is much more apparent.

I learned 30 years ago, that you don't buy the big engine to go faster in s boat, you buy that so you don't lose as much when loaded heavy or on a hot day or higher elevation. The biggest restriction in speed is the hull and pump, not the engine. When you have the small engine(s), even subtitle changes in elevation and temperature, will be more noticeable than on the bigger engines. The 192 erases some of these changes due to its ability to maintain sea level intake manifold pressure to a higher elevation.

 

[Tom V]

I disagree 100% the supercharged, Not turbo charged 192, will not perform well with hot humid air entering the throttle body, this is why we have found success in increasing the size of the intercooler, the cooler the charge the more rpms the engine will spin. The more rpms the greater the speed. Yamaha built the boat with to small of an intercooler, thats why the SVHO intercooler works so much better and so do the aftermarket ones. I work on these boats every day and they all perform the same ( poorly with the SHO intercooler).

 

[mraz72]

I'll take it out and wash the hull, probably not acid wash, and see if I pick up some speed

FYI, the air temps in Rochester NY were barely 70, I think it was closer to mid 60's when I did the run...

 

[Julian]

I'll take it out and wash the hull, probably not acid wash, and see if I pick up some speed

FYI, the air temps in Rochester NY were barely 70, I think it was closer to mid 60's when I did the run...

Wait....you are wet slipped in NY? I assumed you were down south....so there can't be that much stuff growing on your hull....the water is to cold up there for major algae growth (you need to put your location in your personal details). When I wet slipped in IL, my boat never got much growth at all on it. But down here in NC....it will grow fur on the hull!

 

[Matt Phillips]

There can be lots up there growing on his hull. As a kid in Puget Sound, we'd spend 2 weeks on vacation and out boat would be totally covered. It happens fast. I'll put my boat in Tagore this weekend and by the 4th it'll be all skummed up.

My bet is bottom growth....

 

[Tom V]

Check your hoses and clamps around the supercharger and intercooler make sure nothing is loose, you could an air leak and are loosing boost.

 

[Ilmmct]

The more mechanically inclined members have given you better advice, but this video might help for the question regarding condition of the impellers:

 

[mraz72]

Thanks llmmct, I'll pull the boat next week wash it and pull the pump and see what I see....

I'll keep the thread updated when I figure out what the issue is....

 

[Joe Hellaby]

Where's your slip? I'm in Rochester too! But I've been trailering all over the place. I don't think it's you're hull, because that wouldn't explain the less RPM you're getting from the engine.

 

[mraz72]

Hey Joe, I'm at South Point Marina, by Basils on Empire Blvd. You're welcome to come by whenever you want and go for a ride.

The projects I'll be doing is adding a battery and adding an amp and sub woofer and we have the same boat.

I'll most likely wash the boat and take out the pump next week to see what that looks like.

I think RPMs are ok, I'll hit 7800 before heat soak, then I'll hit 7200. Top speed is all that seems to be effected.

 

[Joe Hellaby]

Oh yeah, now I remember you posting in the other thread with upstate NY jetboaters.

Nice and convenient being right near the Yamaha dealer.

I'll look for you next time I'm in the bay, should be easy to spot with the red boat.