1987 yamaha 115 v4 stalls after being at speed for about 10 minutes.

[bluecollerboater]

I have a 1987 yamaha 115. It is on a 18' wellcraft center console. The problem I am having is it will throttle up and get on plane and run fine for about ten minutes then it just dies completely. If i try to start it right away it almost seems like the motor is hydrolocked or bound up. when i wait about five minutes or so it will start right up. After that if i go just clutch ahead it will run all day long. If i go fast it will die in about ten minutes again. Any help with this issue would be greatly appreciated. Thanks in advance.

 

[Silvertip]

Re: 1987 yamaha 115 v4 stalls after being at speed for about 10 minutes.

1) Check the primer bulb to see if it is being sucked flat as the engine begins to die. If so there is a fuel restriction between the bulb and the tank or the vent for the fuel tank is blocked.
2) As the engine begins to die quickly squeeze the primer bulb to see if the engine picks up again. If it does, the fuel pump is weak and needs to be rebuilt. Or there may be an air leak in the fuel line.
3) When the engine dies, check to see if there is spark. If not, something in the ignition system is getting hot and failing.

 

[99yam40]

Re: 1987 yamaha 115 v4 stalls after being at speed for about 10 minutes.

If the motor will not turn over after it dies, hydro locked or bound up, then you need to be checking to see if your over heat alarm is functioning, , check to see if water is getting into cylinders,check compression on all cylinders, and check to make sure you lower unit is not locking up.
The motor should not bind up like that

 

[SparkieBoat]

Re: 1987 yamaha 115 v4 stalls after being at speed for about 10 minutes.

I agree with 99...sounds like over heating to me. test over heat alarm..replace water pump impeller and clean/replace t-stats. also you may have possible clogging in the water passages.

 

[Bamaman1]

Re: 1987 yamaha 115 v4 stalls after being at speed for about 10 minutes.

+1 on above. Replace the tiny thermostats and water pump impeller to start. It sounds as if your engine is slightly seizing. I'm surprised it's not going into fail safe mode. Are you getting any red light on the tach?

You need to tend to this immediately, or you'll face a terminal engine condition.