Yamaha 115 four stroke


Anyone know anything about why this engine runs out of fuel while idling around 1000 rpm? Thought fuel pump so put on a new one but issue remains. Tried most all bypasses in fuel system but can’t pinpoint the source. I can idle for 2 to 3 hours in early morning without stalling but when sun rises and air temps heat up it will happen. I have to pump the primer bulb to restart. It’s a 2014 with 4000 hours I purchased new. Any help appreciated.


“ RBF, quite frankly you are full of schitt. In my opinion you are primarily to blame for the degradation of this particular fishing website. You dilute this place with your incessant desire to be relevant by posting constantly whatever cut and paste cartoon or quip you dig up only God knows where just to be "heard". It really must be miserable where you are, if not for you then for those around you.” EF 4/27/21
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What are you doing Bay????

As an older electric motor gets old...it isn't as effective as new. Do i need to post a vst link? It's not the fuel filter up front.

It's that big piece of metal behind the intake manifold you gots to takeoff to get to...thus measuring pressure to save work.

It's planned obsolescence my main. Check for leaks first. New pump about $80..."No price on a good time."




The ENTER-NET FishermanOriginally posted by mdaddy


It weren’t the primer bulb so gonna pull the vst tank and have a look see just when I need it the most ain’t that always the way.


“ RBF, quite frankly you are full of schitt. In my opinion you are primarily to blame for the degradation of this particular fishing website. You dilute this place with your incessant desire to be relevant by posting constantly whatever cut and paste cartoon or quip you dig up only God knows where just to be "heard". It really must be miserable where you are, if not for you then for those around you.” EF 4/27/21
Bay, before you pull the vst tank

1) Turn the key on and listen to the pump...it will activate pressurization.
2) If it runs out of fuel while running...it isn't necessarily the pump unless the motor in the pump gets warm and fails.
3) When you run an engine from another tank...use no racor fuel filters that are in your boat. Seperate fuel line/bulb/tank.
The racor could have a pin hole...bad gasket...cross thread...you got a leak if it only happens at idle.
4) Measure fuel pressures going into and out of the vst tank.

What happens if you don't idle??? Does it run fine from throttle advance to plane???


The ENTER-NET Fisherman
Bay, before you pull the vst tank

1) Turn the key on and listen to the pump...it will activate pressurization.
2) If it runs out of fuel while running...it isn't necessarily the pump unless the motor in the pump gets warm and fails.
3) When you run an engine from another tank...use no racor fuel filters that are in your boat. Seperate fuel line/bulb/tank.
The racor could have a pin hole...bad gasket...cross thread...you got a leak if it only happens at idle.
4) Measure fuel pressures going into and out of the vst tank.

What happens if you don't idle??? Does it run fine from throttle advance to plane???


The ENTER-NET FishermanOriginally posted by mdaddy AJUDICATOR


Only during idling all other speeds are fine.

I gots 5k worth of plastic n chips in my ears and still can’t hear from growing up on guns and rock music “Nobody’s fault but mine!”


“ RBF, quite frankly you are full of schitt. In my opinion you are primarily to blame for the degradation of this particular fishing website. You dilute this place with your incessant desire to be relevant by posting constantly whatever cut and paste cartoon or quip you dig up only God knows where just to be "heard". It really must be miserable where you are, if not for you then for those around you.” EF 4/27/21
So my shade tree mechanic and mdaddy told me to try a few fixes but nothing fixed the issue. Time allowed the mechanic to pull the vst tank and clean and inspect. What he found was the side cooling chamber was almost completely plugged with salt residue which he cleaned and replaced. This cooling chamber keeps fuel in vst tank at least water temperature so being mostly plugged caused fuel to heat enough to vapor lock fuel pumping but primer bulb had enough pressure to fill vst tank thus the reason for later morning stall after air temperature increase. Ain’t got the bill yet but he said the gaskets were almost impossible to locate and were quite expensive when found. The fix to help avoid this again is to flush the engine with the garden hose attachment below the cowl when I do oil changes.


“ RBF aka Shunkey, Porch Dick, John Weaver, quite frankly you are full of schitt. In my opinion you are primarily to blame for the degradation of this particular fishing website. You dilute this place with your incessant desire to be relevant by posting constantly whatever cut and paste cartoon or quip you dig up only God knows where just to be "heard". It really must be miserable where you are, if not for you then for those around you.” EF 4/27/21
 

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