Jet Boat issue

[AR190_GA]

hi, I have a Yamaha Jet Boat AR190. I recently noticed it sounded like it was skipping and maybe wasn't getting enough water?? I also noticed when the "skipping noise" was happening, the RPMs spiked for a second too. Has anyone had this type of an experience and know what the problem could be? It is a 2014. The only thing that has changed is I did put 93 octane gas in the boat... Not sure that would cause the issue? Another note to add is I have smelled gas or fumes too. I noticed some smoke exhaust when I was pulling the kids on the tube. Any advice would be much appreciated!!!

Thanks,

Bobby

 

[itsdgm]

First off, welcome aboard @AR190_GA glad that you found us and decided to join.

Sounds like you might be experiencing cavitation. Cavitation is a loss of pump pressure. When you lose pump pressure, you also lose cooling water pressure. So things to check would be:

1. Inspect inside the pump. Remove the cleanout plug and inspect the pump and shaft. Also inspect from the rear. Something as tiny as a toothpick or fishing line can cause cavitation. Also, look at the edges of the impeller.

2. Check the intake grate area for missing or loose sealant. Any missing sealant can lead to cavitation too.


It's also possible that you're experiencing some type of misfire in the engine. This would explain the I burnt fuel smell. I'm not too familiar with your type of engine, but I'd take a look at the spark plugs and just replace them to eliminate them as a cause.

Anyway, good luck. Hope you find it soon. You've come to the right place to find the help you're looking for. Keep us posted.

 

[MikeyL]

Bobby ..... We hope we can help you discover the cause of this situation.
What lake do you normally boat on in Georgia ?
And a BIG WELCOME to our Happy Home here !
Best Wishes, Mikey Lulejian - Lake Oconee, GA

 

[JC6275]

I was thinking the same, something in the pump. Could be a small twig or fishing line. Pull the clean out and check for anything obstructing the flow.. no matter how small..good luck, and welcome aboard!!!!!

 

[JC6275]

I was thinking the same, something in the pump. Could be a small twig or fishing line. Pull the clean out and check for anything obstructing the flow.. no matter how small..good luck, and welcome aboard!!!!!

 

[Cobra Jet Steering LLC]

Those engines are not setup to operate on 93 octane they are set to run 87 , the timing for 87 is too late for the advanced timing needed to burn your high test fuel so it is not burning completely. The other issue is probably weeds in the pump making it cavitate, very common issue and easy to deal with when you know what it feels like. If you learn my reverse move it will serve you well but never do it while you have a tow rope in the water.
When all else fails to clear the pump use the clean out plug. I deal with weeds all year long , In 2001 I came up with the reverse move to clear the weeds out of my pump because I had no wish to get in the water to remove weeds in the winter when the water here is a freezing 60 degrees. I like the 90 degree water but getting under a jet boat to de- weed the intake grate is a pain in the neck. Simply back the boat up to about 5 mph , then kill the engines and quickly throw the controls in forward to allow water to back flush through the pump nozzle and out the intake grate, when the weeds come out you will usually see them float out from under the back of the boat. I works nearly every time.

 

[AR190_GA]

Thanks everyone! I boat at Lake Lanier GA. I'll send an update tomorrow after I take a look. Thanks again!

 

[subysti]

If your smelling unburnt fuel then I would check your spark plugs also and make sure all the coils are plugged in tightly. Using higher octane won't hurt but you're spending more than you need to on fuel. These engines need 90 RON minimum. Pumps in the U.S. use the AKI number at the pumps,anti knock index , so an 87 fuel is around 91 RON.

 

[Gthunter5]

How many people in the boat and does it happen during turns?

My 190 cavitates like crazy with 6 people in the boat and pulling a tube around in figure 8's

I attribute it being underpowered

 

[AR190_GA]

@Gthunter5

I thought the same thing, it might be when I have to many people. I took it out with just me and a friend with no turns. Problem was still happening.

Thx! Going to explore the advice tomorrow and will let everyone know.

 

[Gym]

How many people in the boat and does it happen during turns?

My 190 cavitates like crazy with 6 people in the boat and pulling a tube around in figure 8's

I attribute it being underpowered

An elephant in the boat shouldn't cause it to cavitate, it'll only go slower.

 

[AR190_GA]

@Gthunter5

I try to keep elephants off the boat.

 

[jcyamaharider]

I keep them on the boat, just on the surf side.

 

[Englewoodcowboy]

My AR192 cavitated when I had a lot of people on board, not due to lack of power rather than lack of forward momentum at the same rate the thrust was building. The only fix was to ease the throttle rather than slam it to let the hull have time to catch up to the thrust. Other than that I would suspect plugs as well to be your issue.

 

[David Hoff]

It seems very unlikely for the age of your boat, but I ran into capitation problems with my '09 last year. After checking for obstructions and not finding anything, I'd assumed impellers were worn so I pulled them. Upon inspection, they looked perfect (still had factory balance marks visible), but I did notice a few pieces of sealant missing around jet intake. Turns out, *any* type of gap or leak on the intake grates can cause this. After removing and re-sealing the grate, everything is working fine. Take a look and make sure that the grate is 100% sealed all the way around. It's an easy visual inspection (no disassembly required) if the boat is out of water.

 

[njmr2fan]

When I got my AR190 I climbed under to look things over. I noticed that some of the bolts securing the grate to the boat had clear silicone over them, some didnt, some were ready to fall off. Figured it was important if it was there, so I ripped them off and re sealed them. Made sure everything was smooth. Never had an issue. We usually got out with 4 kids a d 4 adults. So maybe 6 full size people on average? Never had any issues with cavitation. Always enough power to pull a tube with kids or kids and adults mixed. I have seen steam, looks like smoke, when Idling after a tube run. I've just assumed that's steam off the heated up motor? Never smelled smoke or anything that's smelled like melting or burning.

 

[Gthunter5]

My Marina has 91 no ethanol. The boat Burns it just fine

You can always go up but never down in fuel

If the boat called for 93 and you ran 87 then you will see the "tuning" issues

4 adults + kids is fun.

6 adults and 2 kids with fuel, yeti cooler, gear I gonna try wake surfing next time rather than tubing

I imagine even if u had a 180hp stern drive you would have the same issue....

 

[njmr2fan]

I'm not sure if it's different in boat engines and car engines, but my dad ran 91 in a Lexus RX300 that called for 87. The valves were replaced under warranty because they were "burned". The service manager asked my dad about gas and told him using the higher octane burned the valves, and to stick with what's recommended. I've always done so since that happened.

 

[AR190_GA]

Thanks for everyone's input! I was able to get under the boat and couldn't find anything wrong. (Everything looked good) since it is under warranty, I took it in... I'll let everyone know what they find.

Thx

Bobby C