Please help! Mariner '95-150 V6 dies when planing

joshmcn27

Cadet
Joined
Jun 26, 2009
Messages
8
I have a 95 Mariner 2 stroke 150 V6 with triple carb. The boat sat up over the winter and was very hard to crank this spring, so far I have the boat cranking and idling great in and out of the water. (replaced fuel, water separator, blew out carb with carb cleaner) It will surge when planing out in the water and the bulb goes soft.

I have replaced all fuel lines, water separator filter and holder (old had bad corrossion), hose clamps,etc. I have used clear line all all junctions to verify I wasn't getting air before the pump.

I rebuilt fuel pump.I don't have a vacuum gauge but turning the engine over the pump does push pulses of fuel

When squeezing the bulb, it will get very hard however quickly loses pressure (when the engine is running or non running). I have tried the vertically orientation and this still happens. I replaced 2 bulbs (attwood was all local guys had in stock) I checked the bulbs just pumping gas from a portable tank and holding the bulb upright with a short hose on the outer side), fuel does not hold at the bulb (slowly leaks down) is this how these valves are suppse to work? do they need back pressure to fully seat the valve?

I have an inline filter on top of the engine after the the pump before the carbs. When the engine is running I can see a air bubble start to form in the fuel filter, it will eventually fill the filter and the engine will die unless the bulb is pumped.

Is my issue my bulb (should the bulbs hold fluid outside of the valve no matter what?), carb bowl needles, fuel pump related? (possibly i seated the plastic discs too tight?

Any help is greatly appreciated!!!!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,134
Your issue is upstream of the primer bulb. If it gets soft, you have a fuel restriction between it and the tank. A clogged fuel tank vent will cause that.
 

joshmcn27

Cadet
Joined
Jun 26, 2009
Messages
8
I took both bulbs and just put them in a portable gas can with hose on each end. The bulbs do not hold fuel above the bulb, gas slowly seeps backward. Is this normal? I tried all of the above with the gas cps off of the tank. I suppose my fuel pickup could have debris? All of the hoses, barbs, and junctions pre bulb are new. There is no anti syphon valve on the tank The tank is alum, I can tell the post is welded. I can't tell if the tank pickup is welded but I believe it is. Any way I can test the pickup without draining the tank and going that route? Thanks for your input?
 

joshmcn27

Cadet
Joined
Jun 26, 2009
Messages
8
I took both bulbs and just put them in a portable gas can with hose on each end. The bulbs do not hold fuel above the bulb, gas slowly seeps backward. Is this normal? I tried all of the above with the gas cps off of the tank. I suppose my fuel pickup could have debris? All of the hoses, barbs, and junctions pre bulb are new. There is no anti syphon valve on the tank The tank is alum, I can tell the post is welded. I can't tell if the tank pickup is welded but I believe it is. Any way I can test the pickup without draining the tank and going that route? Thanks for your input
 
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