AR242 Ran hot now won’t start

[Innovative One]

Hello All,

I recently bought this 2011 AR242 Limited S from S. California, so it was a salt water boat. The boat had the engines replaced almost two years ago now have about 60 hrs on them and I confirmed with SBT they are still under warranty. I brought it up north and the only thing I did before putting it in fresh water was change the spark plugs as they appeared to slightly rusty. I also ran some salt away through the hose ports and then fresh water maybe 3 times a week for two weeks. My intent was to burn some of the old fuel and let the engines warm up and idle after they sat for a while. When I changed the spark plugs I sprayed a bit of corrosion bloc down the cylinders to lubricate any corrosion build up around the valves. Starboard engine appeared to idle a little different than the other, it sounded like an inconsistent knocking sound that would come and go. A friend suggested greasing the impeller as that may have been the knocking noise, which he did. Both engines would start right up every time, both pee holes were draining one a bit stronger than the other. I figured I’d take it out on fresh water.

I idled in no wake mode for about 20 minutes with no problem. Then I went about 5 to 10 minutes cruising about 30mph maybe 5000 rpm and slowly giving a bit more. Then it ran at max throttle 7000 rpm for about 10minutes when I noticed the starboard rpm come down to 6000 and smoke coming out the back. The hole time the pee holes were bursting out water. I immediately let off the throttles and check engine light came on. When I came to a complete stop the engine was off. I rode to shore on one engine the left it alone for about 1 hour. When I tried to start it did but then turned right off. I tried one more crank and left it alone.

While at the beach, I re-checked for obstruction. The impeller, clean out ports, jet intake, and strainer were all clear. This was two days ago, now the boat is home on the trailer. We hooked up the hose with water off to try and start it them turn the water on. It cranked over very sluggish and turned on for about 4 seconds then turned off, it did that about 3 times. Every crank was as if it had low battery voltage and while it was on it seemed as if it couldn’t breath. Battery is good though. Any thoughts would be greatly appreciated in the meantime I get a knowledgeable guy or a time slot at the Yamaha dealer, every is backed up.

I do want to say I was aware when buying this salt water boat and it’s potential issues that may come with it. I would guess the thermostat or some sort of blockage but I don’t know if these are consistent with what the boat is doing now that it’s on the trailer two days later.

This is my first jet boat after I owed a 1995 four wins with fuel injected 5.0 cobra engine. I know 302 but not yamahas.

Thanks in
advance!

 

[Sidarousmg]

i doubt this is the original problem that caused the engine to overheat, but i would remove the spark plugs and check to see if any water was ingested while you were driving with only one engine. How fast did you go on the single engine and did you pinch off the cooling hose?

 

[Innovative One]

Yes we pinched it with a pair of needle nose vise grips once we got to the beach. Not fast at all. I would say 10mph maybe 3000 rpm. From the point it turned off to the beach was maybe 10 minutes going real slow, no vise grips though.

I’ll check the spark the parks plugs, the oil looked clean.

Thanks

 

[212s]

Check the impeller linings. I read that they can corrode under the liners and swell binding up the impeller. That might explain the slow cranking as the starter is fighting against the rubbing liner.

 

[Cobra Jet Steering LLC]

rusty spark plugs ///// check your oil for water in it sounds like water in the cylinders