2001 yamaha 25 hp quits after 5 or 10 min

[raczekp1]

if motor shuts of , then test if there is spark on spark plugs.
this problem is related only to ignition system.igniton coli,cdi, or charging coil{stator if its electi start}
start witch spark plugs change

 

[Sea Rider]

There's a Heat Sensor located between both spark plugs, should be a round thing. Heat Sensors usually trigger up and slows the motor to safe rpm when an overheat is detected, but should not stop the motor. Anyway disassemble it and check the upper part if corroded and where it connects to, both parts must be immaculate clean to work properly.

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Electric components needs to be tested with a multimeter to check their Ohms if inside their specs or completely altered and triggering faster than it should. If all is OK, the motor has an erratic component heating up, shorts, shuts motor, till cools down, motor starts again to miss soon after. An erratic failure it's the most hard to troubleshoot fast...

Happy Boating

 

[Fireman81]

Hey guys, going to test the boat out this weekend. I ended up buying a new thermostat and a new coil. I am going to start with the old coil in it to see what happens.

 

[robert graham]

Is the vent in your fuel tank open and clear?

 

[Fireman81]

yes as far as I know

 

[Fireman81]

Ok guys , This is what I have found out. It was neither the thermostat or the coil. Replaced both of them and still having the same problem. I did find out better what is happening. The motor starts and idles perfect when cold but after going from full throttle for a while back down to idle it is starving for gas and will not start until its cold again. I was able to take the hood off and manualy moving the throttle cable and it will start right up. What would cause the motor to start and idle perfectly when cold like this? Even going down the lake wide open it doesnt skip a beat until you go back down to idle and it dies. Carb has been taken off and cleaned at the shop and they ran it for 3 hrs in their tank and said they couldnt find anything wrong with it but they are only running in a tank also. Any ideas?

 

[rejesterd]

If you're doing something with the throttle cable, and it starts right up when you do that, then I think that points away from it being an electrical issue.

When you first reported the issue, you said the engine would die after running at full throttle for 5-10 minutes. After replacing the thermostat is it able to run at full throttle for a longer time? Also, does the engine ever die when it's at full throttle, or does it die only when you return to idle?

Also, what are you doing with the throttle exactly to get it to start back up again when it's still hot?

 

[Fireman81]

My dad thought it quit at full throttle on him but I think it was always doing it when throttling down I ran the hell out of it at full throttle and it never skipped a beat. It only does this when returning to idle as far as I know. I have only been in it twice so far but thats the only time its done it to me. What I am doing is moving the throttle cable as if the motor were running and accelerating. It starts with just a push of the button when cold but after its warmed up it will not start until cold again. (unless I take the hood off and manually move the cable.)

 

[rejesterd]

Ok, so it's stalling out when coming back down to idle (after it has warmed up). Then it won't start again unless it cools back down or if you blip the throttle cable manually.

That could be the start-in-gear protection needing adjustment. Get the service manual and follow the procedure shown there.

Also check the throttle linkage according to the manual. Something doesn't sound right in one of these areas.

 

[Fireman81]

ok I will be ordering a service manual and trying what you mentioned. Thanks

 

[Fireman81]

So I downloaded what i thought was the right manual for My 25 Hp ELHZ but the manual says F25X. Is this right?

 

[rejesterd]

The manual number for your engine is LIT-18616-01-95

https://www.yamahapubs.com/home/search?category_id=4&year=2001&family_name=F25ELHZ

 

[Fireman81]

Ok it seems to be the right one. I will work on this and hopefully test it out this weekend

 

[Sea Rider]

Check that the cable from the throttle grip doesn't have any bit of slack to the carb at min throttle position with motor OFF. Other issues to verify could be the carb needs a fuel/air mixture fine tuning, or the idle rpm has decreased itself too low due to vibration that will shut the motor when returnig the throttle back to idle.

Will need a tach to adjust the idle screw to the rpm specs factory stated once the fuel/air mixture has been perfectly set. Both adjustments should to be done at idle after the motor has reached it's optimun heat operating range, that's while the boat is adjusted at sea, lake whichever and not running on muffs....

Happy Boating