Fuel issue help needed

 Hi guys

Got a problem with the fuel getting to the motor when I'm going faster. 

When I start the motor it starts fine and will idle no worries. I can drive all day at low speed5-8 knots but when I give it 3/4 to full throttle it starves of fuel. I have a 40hp Yamaha 2 stroke and it is running off jerry can fuel tank. Every time it starts to run out the fuel bulb on the fuel line is sucked in. I have made sure the breather is open on the cap. It has been fine for years and only did it for the first time last week after a service done by boat shop  I put a new fuel line on but still same problem  

Any ideas?

 


Posts: 109

Date Joined: 17/07/14

I'd be tending to think that

Sat, 2016-09-10 09:32

I'd be tending to think that the issue was occuring upstream of your primer bulb if its being sucked in. Breather vent and fuel line would be my first thought as well, but, since you've addressed that, I'd ask whether you had just replaced the fuel line from the engine to a connection fitting on the top of the tank? If so, there still could be the potential for the pickup inside the tank itself - possibly there's a blockage in there? Are you able to open it up, and take a look inside, or, perhaps borrow someone else's fuel tank and see if the issue still presents itself?

Madmerv's picture

Posts: 672

Date Joined: 24/01/15

+1

Sat, 2016-09-10 10:26

 Check the pickup and also the tank connector. The little ball sealer might have a lump of shit just behind it. Try the air compressor blow back method of clearing.

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choc's picture

Posts: 670

Date Joined: 05/01/12

 Thanks for the reply, I will

Sat, 2016-09-10 09:51

 Thanks for the reply, I will try the different fuel tank idea and go from there I guess. 

Posts: 109

Date Joined: 17/07/14

I have a tank you should be

Sat, 2016-09-10 11:50

I have a tank you should be able to borrow if you're interested. I'm a little north of Bunbury, if it helps.

Posts: 315

Date Joined: 07/05/11

Fuel Cap or bulb

Sat, 2016-09-10 14:19

 When this happens loosen off your fuel cap.. If its fixes this its a blocked cap.  

My moneys on a collapsed fuel bulb.. If so replace the bulb and fuel line.  Use stainless hose clamps to connect your fittings.

Maybe replace the connectors too with genuine if theyre old

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 Baron Sportsman

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choc's picture

Posts: 670

Date Joined: 05/01/12

 Thanks Comrad, appreciate

Sat, 2016-09-10 17:28

 Thanks Comrad, appreciate the offer. Got a mate who I will borrow one off.

Travisd, I've put a brand new fuel line on and when I push on the fuel tank I can hear air coming out of the bleeder screw. I'm assuming this would mean it's not blocked?

I'm starting to think it is the fuel pickup so I will try a mate new tank and see how it goes.

Thanks again for everyones input.

Posts: 315

Date Joined: 07/05/11

Intrigued

Sat, 2016-09-10 19:10

 Can you press the little one way on the fuel tank. If you squeeze tank and you can hear air, vent sounds fine.

if u have new line and bulb comrades onto it. It's between bulb and tank somewhere

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 Baron Sportsman

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bennym_82's picture

Posts: 86

Date Joined: 18/05/16

Fuel issues

Sat, 2016-09-10 19:59

If you use a different tank and the issue disappears, might have some foreign material in your tank blocking your pick up line with increased fuel flow?