Yamaha fuel fitting problem.

[XD351]

G’day Raiders,

This one is pretty long winded but I thought I would post it in case anybody has the same problems in the future .

A few months back I decided to renew the fuel line fittings on my boat ( duel 24lt tanks ) and it has been giving me grief ever since , the problem is when I take the tanks out to fill them then plug them back in or disconnect the fuel hose from the motor I would either have issues with the primer bulb going hard instantly or it would remaking compressed or squished when I squeezed . The first issue was fixed by disconnecting the hose and re connecting it to the motor - at the time I thought it might not have been pushed home fully and as I didn’t need to disconnect it again the problem went away . The second problem was fixed in a similar manner and it it gave me grief at the ramp I just disconnected the fuel hoses nd reconnected them or flipped over the three way valve that connects the two tanks to the main fuel line that runs to the motor . This was an intermittent sort of thing but I had never had this problem bother me once in the previous 20yrs of use and  the original tanks were the genuine Yamaha tank that came with the motor and a sceptre tank I bought and fitted , the tanks really only fitted in one way so the sceptre was always on the port side and the Yamaha on the starboard. When I ran the original fuel line I cut one fitting off the original fuel hose as I had to join it to the hose that runs under the floor and I re used this fitting ( without realising it ) on the hose running to the Yamaha tank and a new fitting was purchased for the scepter tank . 20yrs on I decided to ditch the sceptre as it was difficult to remove and it was replaced with a Yamaha tank which fitted in much better , while I was there I decided to renew the connectors on both tanks,  the motor and all of the fuel lines -all seemed ok . The first trip out was ok and everything worked as expected but the second trip is where it all started to fall apart ! Dropped the boat in the water and went to prime the motor but the bulb just went rock hard instantly , I had a bit of a scratch of my head and thought I would try reconnecting the line to the motor and this fixed it - or so I thought ! This time I started to prime the engine but the bulb just went spongy and eventually it wouldn’t expand back out 🤬 so I out came the tanks and the connectors got the same treatment as the one on the motor - the bulb popped out , the engine primed and I got through two days of use with no issues 😀. I didn’t need to re fuel for the next two trips so they also went without any problems but last weekend the spongy bulb problem reared it’s ugly head again as I had to fill one tank , this was fixed as before and I thought great - I can forget about this for the day and put it at the top of the list of thing to do when I get home . I think I got maybe 2km down river and the engine started to die as it would if it was running out of fuel so out came the tank and I stuffed around with the fitting and away it went for most of the day ( I did originally think I had left the air breather on the cap closed but it was well and truly open ) . It did this on the way back as well but I gave the primer a work over and it seemed to disappear which now really confused me as it seemed it wasn’t getting enough fuel or was sucking air but from where ? I spent a good thre hours stuffing around with this today , testing for air leaks in the hose ( unplug the tanks and fit a tank to the engine side of the fuel hose then squeeze the bulb until it is flat ,disconnect the tank and release the bulb which stayed compressed for a good half hour with no change ) so no air leaks there ! Fitted one tank to one side pushed down on top of the tank to push some air out through the breather then locked it tight - the other end of the hose was disconnected from the tank use previously and known not to leak but the tank slowly popped back into shape and when opening the breather I should have heard some air rushing in but I didn’t - this was dome multiple times on both tanks for the same result - the coupling was leaking air but not much so why was the engine starving for fuel intermittently? After scratching my way through my scalp and wondering why it is so ,I went into the shed and pulled out my box of boat bits and in there I discovered what I think might be the answer - the original genuine Yamaha fuel coupling ! I had a bit of a gander at it and both looked similar , I looked at the fittings on the tanks and I could see no difference between the two and then I noticed the little pin sticking out of the fitting on the tank (this is a valve to seal the tank when not connected) so I though it might be jammed or sticky - it wasn’t but they both needed some force to push them in and as this force was equal on both tanks one of which is brand new I thought it couldn’t be them . I then turned my attention to the female fitting and this has a spring loaded ball bearing to seal the fuel fitting when disconnected, I dug out a small screwdriver  and gave the ball a push on the genuine fitting and it was also quite firm so I tried the new fittings - almost no force whatsoever to push the ball in ! I appears that what is happening is the spring on the ball bearing isn’t strong enough to push the pin in fully on the tank fitting and the pin is slipping off the side of the ball which means the valve either doesn’t always open fully or it doesn’t open at all and this can be a bit hit and miss . I then connected a short length of hose to the genuine fitting and did a good dozen or so cycles of connecting and disconnecting and checking the valves were open by sucking or blowing into the tube - didn’t fail once and I could suck vacuum into to tank and it held so no air leaks . I now have to hunt down some genuine fittings and rid myself of these cheap made in China heaps of junk and the primer bulb bought from that big chain store we all love to hate doesn’t impress me either- might see if they do genuine on these as well .
As a side note the pin pressure on the fitting of the sceptre tank was very light so this explains why that tank worked with the cheap fitting that I fitted 20yrs ago and the Yamaha tank was never fitted to that side .

Fitting on the tank arrow showing  the pin for the valve 

The fitting on the hose arrow showing the spring loaded ball 

Edited May 8, 2023 by XD351
To add photos

[zmk1962]

Great diagnostic work and tip Ian ... glad you were able to chase this down and sort it. Long term that weak spring/ball connector would have been leaning your fuel out and that is not good for the motor.  Good job!

Cheers Zoran

[XD351]

Thanks Zoran !

[BaitDropper]

Now that would have been a very frustrating episode XD..  Imagine if another boater, with less experience than yourself experienced this. You kinda here quite a few similar type issues occur like this, I was at Greenwell point a few weeks back for a morning coffee and outing, ended up giving a couple of blokes on a newly purchased boat try and solve an issue, similar to yours.  They decided to take it back to the shop where they purchased it after no success tied up at the ramp, but it does make you wonder..

Kudos for identifying the issue, no better feeling than diagnosing an issue fully...

 

[XD351]

Thanks BaitDropper ! I have some genuine connectors on the way but I doubt I will see them before this weekend so looks like a lure session down the parra river or if the swell dies down enough I might hit the beach-always good to have a few options !

I had a look at a new genuine fuel hose and primer set -$130 bucks! - I think I will persist with the aftermarket one for a while longer 😂

[noelm]

Genuine connectors rarely give issues, aftermarket copies are a mixed bag. Also lots of fittings look the same, (different brands)  but they are not. Manufacturers change things over time, and what fitted a certain model might look the same, but, it's not compatible with some other models.

[XD351]

The thing I find annoying is my local outboard place is a Yamaha dealer and the fittings he sells are the same brand I got from the big store , he could probably order them from Yamaha - if they have any stock .if the genuine ones I have purchased last 20yrs like the last ones I will be too old to care and the the boat would be 40yrs old !

[noelm]

Some parts are OK aftermarket, but that sort of thing, ONLY genuine, and that includes primer bulbs, the cheap ones are rubbish, if your dealer doesn't have genuine, get them to order a couple, the difference in price is not that much when you look at the big picture.

Edited May 9, 2023 by noelm

[BaitDropper]

Yeah, agree with what Noelm is saying, it can be all very frustrating for some I bet. I wonder how many issues for " less than hands on " boaters that this would have caught out.

But as mentioned XD, you identified the issue....

[dunc333]

i use moeller bulbs pricey but like tank fittings you get what you pay for i guess  well done with the diagnosis xd cheers dunc333

[XD351]

All now fitted with genuine Yamaha couplings and primer bulb - one thing I noticed is the genuine couplings are much harder to push on . I fitted a male coupling into the motor end of the fuel hose and placed that in a bucket so I could test the fittings on the tanks - disconnected and reconnected and pumped fuel through half a dozen times on each tank and no problems, the motor end connected ok and the engine primed up quickly - way quicker than the aftermarket bulb because the ball valves inside the aftermarket bulb were not sealing at all . The cheap couplings are fine with aftermarket tanks and fittings but if you have OME tanks and fittings it is probably better to stick with genuine fittings regardless of what brand your motor is .

Now hoping I can get out next weekend for a fish and motor test ( or possibly during the week to do a test run up the parra river ) and finally put this drama to bed ! 

[noelm]

For the difference in price, I don't know why people go for after market, I think it's how we have been brainwashed to go to supermarket style chain stores? There also different types of fuel primer bulbs, the ones with a marble/ball in them must be mounted vertical to work (with the arrow pointing up) or they won't prime, or the fuel will drain back to the tank! Then there is the hose size to match the barb on the bulb. Genuine bulbs are great to use, prime fast and last for years and years, just like the end fittings, cheap copies kind of work, and are readily available if you're stuck on a Sunday, but long term they are trouble waiting to get you. Even fuel line and filters vary in quality, I use only genuine oil filters and brand name fuel filters.

[jeffb5.8]

My kids tinny with a 15hp yamaha had a genuine connector on the aftermarket fuel tank and aftermarket fitting going to the motor

 

I ended up switching them around as it never quite fit correctly and no problems since

[XD351]

Just a final update on this problem - went out today and ran all day with zero problems with  plenty of full throttle runs and the yammie didn’t miss a beat , to say I’m happy is an understatement 🤣