Yamaha 70 TLRY not keeping prime at full throttle

[gatorsc]

I have a 2000 model yamaha 70 TLRY. It will run fine up to 3/4 throttle. But once I open it up to full throttle, it looses prime. It will run at full throttle, but I have to assit it by pumping the in line priming bubble. The vent on the tank is open, and fuel connection look good. I replaced the priming bubble, but still having issues. I do have a water seperator on the system, and putting a new filter on it now. Just wondering if anyone had any suggestions on what else to try. Still wondering if maybe a loose fuel line connection some where could posibley allowing it to "catch air" and not run properly. Any input is appreciated!

 

[robert graham]

Re: Yamaha 70 TLRY not keeping prime at full throttle

Maybe you just need to replace the fuel pump. Everything you've described points to a bad fuel pump. Good Luck!

 

[pman]

Re: Yamaha 70 TLRY not keeping prime at full throttle

Gator- Did you try replacing the fuel pump as Robert suggested? I have the same 2000 70hp Yammy with the exact same problem you have mentioned. Never even thought about the fuel pump, but that certainly makes sense!

Pearsall

 

[99yam40]

Re: Yamaha 70 TLRY not keeping prime at full throttle

It is best to test the fuel pressure and vacuum it can and does pull and see if it is sucking air into the fuel system. That will point to any problems

 

[Jockey]

Re: Yamaha 70 TLRY not keeping prime at full throttle

How do we test that 99yam40 I have the same problem on a 2002 F60.

 

[99yam40]

Re: Yamaha 70 TLRY not keeping prime at full throttle

search in the frequently asked part of the forum for testing fuel system

 

[stylesabu]

Re: Yamaha 70 TLRY not keeping prime at full throttle

i chased it problem for 6 months didn't happen all the time.it turned out to be an o-ring in one of the quick disconnects. I happened to see it drip on day in the driveway. i had pumped up prime and just let it sit. it should take hours for it to get. ive seen other stay hard for a day.point is smallest leak can cause loss of prime.fuel pump kits are pretty cheap and like water pumps should be replace as prevent maint.