Just bought 17' Cobia with a 80 horse 2 stroke

[hondakillrsx]

Hey guys,
So I just purchased a new boat yesterday! It's a 17 foot Cobia with a Yamaha 80 hp 2 stroke. The boat and motor seem to be in great condition but he did mention a problem that has happened twice now and I just wanted to get some opinions before I bring it in to the shop.

What has happened, what he says is twice now, is that the boat will be running fine at 4 thousand or so rpm's and it will all of a sudden loose gas and the motor will start to 'stall' or slow down because of lack of fuel. The last time it happened he just slowed the boat down, went to the back and the ball was flat, he pressed it to put more fuel into the carbs and it ran fine after that. The first time it happened he said he 'blew out the tube leading into the fuel tank (below the separator) and it worked after that (thinking there was something blocking the line). What do you guys think I should try. he said he replaced the fuel pump a year ago. It ran fine after he repumped the ball. the ball looks new as well so I dont think it is that.

Question: Is it possible to just switch to a electronic fuel pump from a manual like you can do in cars? Thanks!

 

[hondakillrsx]

Re: Just bought 17' Cobia with a 80 horse 2 stroke

anyone? Any input helps

 

[dogdad]

Re: Just bought 17' Cobia with a 80 horse 2 stroke

I've been wrestling with the same symptoms on a Suzuki 85 2-stroke.

I've been reading some posts that suggested it could be a sticking anti-siphon valve at the fuel tank. Curiously enough, there's also some question as to whether outboards (of our size) have or need an anti-siphon valve. I haven't found the time to tear mine apart yet to check anything, but will do it soon.

HTH. Be interested to hear what you find, too.

 

[99yam40]

Re: Just bought 17' Cobia with a 80 horse 2 stroke

no an electric fuel pump is not a good idea because of possible fuel leaks that are dangerous in a boat and the anti-siphon valve is there to keep the boat tank from draining(siphoning out) into the bottom of the boat in case of a fuel line break of some type.
Just some thoughts

A quick test with fuel pressure vacuum gauge should show any restrictions or fuel supply problem

 

[dogdad]

Re: Just bought 17' Cobia with a 80 horse 2 stroke

99yam40 -
Question for you... is the anti-siphon valve at the lower end of the actual pickup tube (ie, the vertical tube sticking down into the tank), or the barbed/threaded fitting where the fuel-line is connected? Reason I ask is that West Marine catalog (and others) show the valve as being (or a part of) the barbed connector, yet from some descriptions I'd think it was down in the tank itself.

This thread got me to make the time and go down and look at my configuration just now. The barbed connector is just that - a barbed connector. Do i not have an AS-valve or is it in the tank? I tried to take the tank-mounted fitting off, but quit for fear of cracking the plastic tank or something.

Any insight would be helpful to me and the OP. Thanks

 

[99yam40]

Re: Just bought 17' Cobia with a 80 horse 2 stroke

Not sure as I have always run small portable tanks on mine, but I think the AS should be at the fitting and maybe a screen at the bottom of pick up tube.
As I said testing is the way to go