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Yamaha 25hp 2 stroke issues

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dmarsc10

New member
G'day, I am after some advise on an issue i am having with my Yamaha cv 25 (2007 model i think). From cold it starts as it should..... prime the squeeze bubble, couple of pulls with the choke out, choke in, then she'll start and run fine. However, randomly (not every time) after stopping the engine i have trouble restarting. What happens is she'll fire up without a problem, idle for a few seconds then cut out like its out of fuel. When this happens it will not restart without re-priming the squeeze bubble no matter how many times i pull the cord or use the choke (obviously the choke should not be necessary at this stage as the motor is well and truly warm). If i re-prime the squeeze bubble it will start easily with one pull and run fine until i next shut down the engine. I am fairly certain that there is no air leaks in the fuel line. I have replaced the squeeze bubble and ensured that the one way valves in the bubble are working correctly. The squeeze bubble gets hard as it should when i need to use it. Could the problem be with the fuel pump? Any thoughts would be greatly appreciated and if necessary i can purchase a new fuel pump assembly and replace it (if this is a relatively easy DIY?).
Cheers.
 
Try operating the manual fuel pump first when the motor is warm.----Sounds like fuel is evaporating out of the carburetor when motor sits and is warm.
 
Thanks racerone. On some advice ive tested the fuel pump by removing the fuel hose where it enters the carby and there seems to be a good pulsing flow, so I don't think that the fuel pump is the issue. If it is evaporating from the carby how do I fix it? This issue drives me crazy. I've got a friend who used to own a 30hp yamaha (very similar engine) and had the same issue but couldn't solve it. Surely someone out there knows the fix?
Thanks again.
 
The fix is to operate the manual fuel pump ( squeeze bubble ) when you want to start the warm motor.----------Basically you need to experiment / learn how to start the motor when warm !11
 
Don't mean to sound unapreciative of your replies, but I have owned a few boats/outboards and I know that something is not right when you have to prime a warm engine 1 out of every 5 or so times (randomly) and the rest of the time it starts perfectly with half a pull. It is a pain in the rear end.
 
The issue is not really that it won't start (it starts very easily when warm) its that when it does start on that random occasion, it will run for 5, sometimes up to 10 seconds, then die..... then refuse to start again without being manually primed. Using some throttle or choke on these occasions does not help either and in fact will make it die quicker.
Thanks again for any help offered.
 
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