correct size fuel line - Yammy 115

[scottoz]

Hi all - my 93 v4 has what looks like standard grey yammy fuel line plumbed up into the carbs and from the engine. It does not have a fitting in the cowl - is this normal?. It looks like 5/16th - I thought it would have to be 3/8th. I have run 3/8th to it and a large (3/8th fittings) tempo (USA) primer bulb. I notice that it primes quicker than the old set up of small bulb and 5/16th line - but only to the point of meeting the smaller diamter hose I guess - can only flow as fast as the smallest opening allows it. Does the Yammy come standard with the larger diameter?<br /><br />Next question - why does the oil buzzer come on if I leave the motor tilted (fully or so)_up for some time before start up (when lowered). Is it because the oil level float in the engine tank needs to settle down.<br /><br />Cheers mates

 

[rickdb1boat]

Re: correct size fuel line - Yammy 115

3/8" line is the best size fuel line for your motor. If you can run it all the way, much better. As you said, it can only put out as much as the smallest hose. I don't know if your Yamaha came standard with the 5/16" line, but it would not surprise me if it did. See if you can run 3/8" all the way to the pump. The alarm is probably doing exactly what you are saying with the float level. If it does not go off when running or in the tilted down position, it's fine.

 

[rodbolt]

Re: correct size fuel line - Yammy 115

hello<br /> the original fuel line was 8mm or about5/16ths. it will run fine on it. the tempo primers dont like sun. be aware. the float should not react like that in the tank. could be the float strainer screen is not installed correctly or its clogged.<br /> you would have to watch it as you tilt the motor down is the tank still full? your symtoms are abnormal and would bear a look. ifyou attempt to remove it be aware that the strainer gasket must be recovered and replaced each time the strainer is removed and the vent hole in the srainer must go over the flat on the sensor. I drain the tank through the water trap before removal to prevent trash from going down the pump intake line.<br /><br /> good luck and keep posting

 

[rickdb1boat]

Re: correct size fuel line - Yammy 115

Rodbolt, thanks for the update info on the fuel line size on the Yammy. I knew some motors come with 5/16" line, but wasn't sure if his did. But just for my own info, would a 3/8" line be better on that size motor? What if he was low on oil in the tank. Would that cause the alarm to go off if tilted?

 

[rodbolt]

Re: correct size fuel line - Yammy 115

hello<br /> RB its not supposed to. it is possible maybe. I would have to have the excact conditions. my 115 never does that. 3/8ths line is more common and will tolerate bends better before the restriction becomes to great. test fuel system vacum at a tee between the engine filter and the pump. should be less than 4"hg at wide open throttle for all yammis under 200 HP

 

[DJ]

Re: correct size fuel line - Yammy 115

Go with 3/8" or better. Just because it's there, doesn't mean it will use it.<br /><br />Outboards cannot be starved!

 

[scottoz]

Re: correct size fuel line - Yammy 115

Thanks all - Rodbolt - the exact conditions are these. I tilt the motor up fully so that it is close to right angles with the boat. I leave it like that for several days. I then trim it down fully and attach the ear muffs and turn the ignition on - the buzzer screams and the digi oil combo guage flashes and does not stop flashing after about 1 minute it stops (I can hear the oil pump working during this time - or part thereof) and I then start the engine. If I leave the engine down for several days it simply screams for a second or 2 and the guages flash their normal start up routine and then the arrow stays on the green flag (for full main tank oil)and I start up. <br /><br />It is consistent and only happens when the motor is left fully (or very near to it) up for some time.<br /><br />Cheers