Maxum boat after about ten minutes in water she starts to miss fire an comes to a stop give it two r three minutes and she will go but not for long ,any body any idea of problem

Kind of sounds like a short in that engine's electrical system. Not sure why it happens after 20 minutes, but perhaps that's when it gets warmed up and the choke comes off. Check the wires for spots where they could rub on a surface and cause a short.

Check this link out Paul. Maxum 3500 SCR Strong Economy

If you are asking about the speedometer, it runs on air pressure coming thru a small tube from the rear of the boat. Some have a separate pitot tube hanging off the back of the boat, some have a pickup on the lower unit. All have a small hole that can get clogged. look to the back of the boat for your style.

CHECK COIL OUTPUT WHEN IT STOPS RUNNING. A HEATED COIL CAN HAVE INTERNAL WIRING THAT LOOSES CONNECTION AFTER HEATING UP

May be one of the fill valves are not opening when it is calling for either cold or hot water. Have the solenoids checked with an ohm meter

Try using non-ethanol gas. It's death on small engines. Starter fluid gives it a boost if higher octane. Have a reputable repair place clean out the gunk, then use good gas. Best of luck finding non-ethanol. Boating marinas carry it.

heavy rain and surface water is all you can hope to drive through.IT IS NOT A BOAT.you were lucky it restarted,and could have cost you at least another engine.

possibly a head gasket going bad before taking off one morning pull the plugs don't know if u have the v6 or the 4 banger based on ur info but 1 or 2 of them maybe getting water in the cylinders and after running for awhilethey dry off & start firing pulling the plugs is ur easiest way 2 check ur problem now or later!!!!!

Here is what you do. make sure the battery is fully charged cause you dont want it to go dead during this process or it wont work. step down on your parking brake pedal and leave it down. this will keep the headlights off during the process so the battery wont go dead. turn the ignition key like you were going to start the car then leave the key in the on position. you have to leave the key in the on position for ten minutes. during the ten minutes you will see the anti theft or security light flashing or the display in the instrument cluster. when the ten minutes are up the security light will go out. once the light goes out attempt to start the car. if it doesnt start turn the key all the way back to the off position count to three then attempt to start the car then leave the key in the on position another ten minutes till the light stops flashing again. sometimes it takes up to three ten minute cycles to reset the antitheft system. so basically you do the same thing three times leaving the key in the on position for ten minutes each time so it will take approximately thirty minutes. sometimes it will work on the first try though.

With the newer yamaha jet boats your route of easiest resistance is gonna be to take the boat to a Yam dealer so they can put a diagnostic machine on it. Alot of sensor problems can be solved much easier and cheaper after running the diagnostic and pinpointing exactly what the issue is. The lights on the dash are for high temp and low oil. If you checked the water temp and it seemed ok, check your oil levels.