07 Yamaha AR230 Engine Vibration

[davidqueen.t]

Hi everyone!

I have a 07 Yamaha AR230. I’ve had the boat now for 3 years and these forums have helped me tremendously in all the upkeep/fixes for the boat. but I can’t seem to find the solution for my new issue.

My last day on the water in ‘23, while towing a tube, the starboard engine started making in what I can only describe as a noticeable vibration/sound difference when over 4K RPMs. Immediately I thought that I sucked something up. My plugs have been stuck and at that time, I was hating my procrastination in fixing them. Anyways, after getting the boat home, I pulled the pump and there was nothing in the impeller or surrounding areas.

I’m reading a lot about cavitation. Should cavitation only be noticeable on the water? Today, in my driveway, I connected my hose and quickly tested the engine over 4K RPMs and it is still making the vibration/sound.

I believe my thrust out of the starboard engine was very minimal in helping me get back to the dock. Today when running the engines separately, and with quick engine revs, the port engine would thrust the water against the garage door but the problem starboard engine would not. This could be nothing but I thought I’d include the observation.

Any thoughts, links to other threads would be greatly appreciated. Thank you all!

 

[Scottintexas]

Since it’s make the same vibration on the hose I don’t think cavitation is your issue

I would pull the impeller and run the engine to see if the vibration is still there

If not then you’ve narrowed it down to the impeller/ shaft / intermediate bearing

If so then you’ve got an engine issue

Have you ever looked at the bearing under the cone on the impeller?

 

[Babin Farms]

When was the last time you changed spark plugs? Simple & cheap to change them out and see if maybe a plug went bad. At the very least pull them and inspect to see if one doesn’t look like the others. Also check the oil. Make sure that you’re not “making “oil with a possibly stuck injector.

 

[davidqueen.t]

Thanks for the quick reply’s!

I’m going to try and work on your suggestions tomorrow. I replaced all spark plugs two seasons ago and the intermediate bearing at the start of last season.

I’ll let y’all know what I find out.

Thank you!

 

[Cobra Jet Steering LLC]

M R 1 engine may have a dirty air cleaner filter especially if the oil was overfilled by accident so check that also

 

[Babin Farms]

Thanks for the quick reply’s!

I’m going to try and work on your suggestions tomorrow. I replaced all spark plugs two seasons ago and the intermediate bearing at the start of last season.

I’ll let y’all know what I find out.

Thank you!

That’s a long time for spark plugs in these engines. It’s good preventative maintenance to change them each season.

 

[Cobra Jet Steering LLC]

Also remember the spark plugs are the report card of the engine and you should look closely at each one as you remove it

 

[Cobra Jet Steering LLC]

and inspect the motor mounts be sure none are broken

 

[davidqueen.t]

I was able to test everything out and I believe I may be looking at an Engine issue.

1. air filter was clean
2. changed spark plugs - no change in vibration
   1. I did find a bolt while cleaning the engine area a few months ago. I could not find where it came from. But I did today, it bolts in the ignition coilassy which goes over the spark plug. Another project ahead of me as the bolt now doesn’t tighten.
3. Pulled pump/impeller- cranked, still no change
4. Engine mounts appear to be fine.

I’m up for getting in the engine but I do have my limitations. Unless I can find or the community here has a really good idea of where to look, I may just take it to my local mechanic.

 

[Cobra Jet Steering LLC]

ok did you really look close in the hub of then impeller that is vert difficult to view because just a small piece of fishing line will do exactly what you are describing

 

[Babin Farms]

Did all of the spark plugs look the same brownish color or was one or two black or wet? Do you check the oil??? Was it overfilled or smell like it had some gas mixed with it?

 

[Cobra Jet Steering LLC]

Having a loose ground on the coil could also cause the engine to misfire, another thing is if the gaskets are leaking on the exhaust manifold and allowing water in the oil that brings up the oil level and puts it in the intake but he said the filter was clean so probably not the issue of water in the oil.

 

[davidqueen.t]

Thanks all! I’m in the boat now:

1. engine mounts are good
2. Oil appears to be fine, no gas smell or big color difference
3. Checked the hub again for fishing line or anything small, nothing.

Here’s a picture of the spark plugs. New one on the left, middle plug was the one under the loose coil in the back. The one on the right is how the other three looked.

 

[Mech]

I don't think you should have that carbon build up way up on the threads like that.
Did the plugs feel loose coming out?

 

[davidqueen.t]

I don't think you should have that carbon build up way up on the threads like that.
Did the plugs feel loose coming out?

They did not, they were all tight.

 

[Cobra Jet Steering LLC]

The loose coil probably caused it to misfire be sure the coil is grounded correctly the last one is what it should look like. Also you have an MR1 engine and those were bad about the number 3 plug snapping off when people were trying to remove them, you can see the carbon on the bottom of the plugs , that is due to the plug end being in the combustion chamber. Research the thread lock on the plugs subject I always do it just a slight amount and I go 1/3rd turn past when the spark plug stops and it works fine I also use dielectric grease on my spark plug boots to avoid issues with the coils and keep out moisture as well as white lithium grease on all the electrical connections .