2005 90hp Mercury stalled during deceleration

[triton75]

Hi folks, had a weird occurrence happen yesterday at the lake. After running a few miles down the lake @ wide open throttle, once i pulled back on the throttle the motor died...weird right?! So, i turned the key, she fired right back up and idled just great. No issues/symptoms of any kind during WOT, boat ran great. This stall happened twice... Any idea??? The motor is a 2005 Mercury 2 stroke 90hp, Thanks in advance.

 

[racerone]

Water in the fuel ?

 

[triton75]

Not sure... i wouldn't think so. I keep the boat under a shelter and always run non-ethanol fuel in it. Matter of fact, i'm about to fill up again so, we'll see if it's fuel related.

Could this be a primer bulb issue? or fuel line? spark plugs? Keep in mind that @ full throttle and idle it runs great...

 

[racerone]

Primer bulbs do nothing once motor is running

 

[triton75]

Gotcha. Thanks for the feedback. Any other ideas?

 

[Texasmark]

Primer bulbs do nothing once motor is running

If they are cracked and the fuel pump is sucking fuel from the tank, path of least resistance is air through the crack, not fuel from the tank......seems to me. I never took one apart but I assume there are 2 check valves inside the bulb...one to block off passage to the engine when releasing the bulb and the other to block fuel going to the tank when squeezing. Otherwise how could it possibly work. In that regard, a malfunctioning (how????who knows) valve could stop the fuel flow.

Other thing it might be would be a blob of water injested alcohol. I had it happen on an OMC. I had a built in tank and was worried about condensation so I put in a can of water inhibitor....way before ethanol....mid 1970's Johnson 125 V4. Was blasting across the lake and it stopped. After some tearing things apart, I found it....the blob which was stuck at the inlet to the fuel line connection from that tank that connects to the engine.

Cut off the hose at the connection, used the squeeze bulb to pump fresh fuel out of the hose, thus causing the blob to exit and that was the end of that and me adding supplements for water in the tank.

 

[Texasmark]

Another theory. The clutch dog in the lower unit is shaped like a saw blade on the F gear end so that when decelerating and the engine rpms drop below the rpms corresponding to the speed of the prop at the time, the prop will disconnect from the engine drive, continue with it's speed governed by the water passing across it, not act like a boat anchor (blades turning slower than normal and significantly reduce boat speed), possibly bringing the boat to an abrupt stop or close to it.....which I had happen to me at about 30-35 mph one day and almost had a mouth full of windshield. If the lower unit has water in it and water damage, something of the sort is possible.