AR210 throttle, or cavitation, or something issue.

[Justin Bentley]

please excuse my lack of proper terminology and knowledge new boat and jet boat owner. throttles respond in sync out of the hole, and stay in sync until about 4500 RPM. at 4500 RPM the left side (sitting in the drivers seat) starts falling off. I can feather the left side up to about 6000 RPM while the right side performs like normal, revs normal, responds normal, and acts like it should. at full throttle the left side hovers around 6k and the right side will rev to the top end. i have nothing around the impeller that i can feel, visually i think it looks fine, and unobstructed. this happened on the first time out for this season, and the boat was acting fine on the last outing last year. I changed the oil, the spark plugs, etc. the one thing i did different was adjust the slack out of the throttle linkages to make the throttles hit the throttle bump at the same time. I am going out right now to inspect the underneath inlet and see what i can see, my question is an i looking in the right spot or is this a motor, throttle issue? thank you in advance and please feel free to dumb things down as much as possible. I have auto mechanic experience but cars don't float so i am out of my wheel house. i will send a few photos of what i found shortly.

 

[Ilmmct]

I am not one of the mechanically handy guys on the forum, but I remember watching this video, perhaps it could help your boat’s behavior:

 

[Justin Bentley]

Thank you Ilmmct, I will check it out and make the proper adjustments, yesterday after posting i found an instruction video on how to pull the impeller. i pulled the impeller and found nothing that would cause any concern as far as the shaft, or impeller. i did however find that i have some areas that looked like they needed some silicone. I plan on pulling as much as i can apart and sealing everything up. then smoothing all the possible ridges that could cause turbulence. does anyone have a silicone type or replacement that they use that they would like to recommend?

 

[Ilmmct]

@Justin Bentley I am not the guy to advise on the mechanical issues, but I believe this recent post has some breadcrumbs and a url that might help you.

 

[Brian]

@Justin Bentley Did you find the issue. Our ar210 is having the same issue.

 

[itsdgm]

@Justin Bentley Did you find the issue. Our ar210 is having the same issue.

Welcome @Brian and sorry for your issue.

Most engine related issues on our vintage boats can be fixed simply by changing the spark plugs. Have you tried that yet?

Anyway, good luck. Hope that helps. Also, more info might help diagnose your exact issue.

 

[Brian]

Yes I tried this first thing. We always keep and extra set of plugs on the boat.

It actually ended up being an ignition coil. I swapped them from one engine to the other and the symptoms switched engines too.

Now just to find one somewhere in stock. We just happen to be on vacation this week at Kerr Lake, VA

 

[itsdgm]

Yes I tried this first thing. We always keep and extra set of plugs on the boat.

It actually ended up being an ignition coil. I swapped them from one engine to the other and the symptoms switched engines too.

Now just to find one somewhere in stock. We just happen to be on vacation this week at Kerr Lake, VA

Great diagnosis. They use those coils on all WaveRunners and boats with a MR1 engine. I’d imagine that most dealers, rental site repair shops or even a seller on eBay that could overnight one to you would have something that would work.