Hello Everyone in advance,
First off let me say I really have found these forums helpful in the past, but I am having issues finding the problem I am having. I feel like this should not make a difference, but both times this happened this weekend, I had the lower unit fully tilted up while on a beach, then lowered before starting (at least that is what I recall).
I will get the engine serial number but it is pouring rain right now and I don't know when it will stop. Engine is an early 2000's MerCruiser 5.0L EFI, ECM is a version 3/4 type. Lower unit is an Alpha 1.47R with the serial number of 0L946190.
Both times this happened I had been pulling people tubing so the engine had been running fairly hard. I pull up to shore, shut the engine off, then pull up the lower unit all the way. Get ready to take the next person out and as soon as we get away from shore, the engine starts fluctuating RPMs from 700 to 2000 a couple times then dies.
I would crank it and then it would start a couple times then die immediately after, then it felt like no amount of cranking could get the motor to start again. Every time I turn the key to run or the engine dies I can hear the fuel pump run for a couple seconds then stop. The pump does sound rather odd like it has a bunch of air in it or something. It certainly was not a smooth sounding pump (I am not sure how these act normally). Both times this situation happened I would try cranking off and on for 10 minutes then give up. I let it sit for an hour and try cranking again. After another 10-15 minutes of cranking, the engine would start to sputter and fire, then die. Then after 5 minutes of that and trying to give it some gas every time I got the engine to sputter, it would finally fire back up and run normal with idling around 600 RPMs and I would have my full power band.
The second time this happened it was the exact same scenario where I had just taken someone tubing, lifted the lower unit up all the way to pull up to a beach, then leave and get all those troubles again.
Things I tried:
Taking off the flame arrester and observing the injectors I am seeing fuel delivered while cranking. I checked all the ECM connections and they all looked snug. I did notice the nuts holding the ECM in place were loose so I tightened those up. My cable going from the coil to the distributor looked fine and I am fairly sure I am getting spark as I could get the engine running well both times after the hassle.
Things I have not tried that I would like to:
Take off the fuel/water separator and see how much water is in it (when I fill with gas I put in a bottle of SeaFoam each time to help stabilize the fuel longer as I am not out every weekend). Once this is done if there is water in it can I reuse the filter after I dump it out and refill it with gas?
Take the fuel pump out and inspect for any oddities (Is this even possible? With the way it was sounding am I just looking at a new fuel pump?).
Check the pressure from the fuel pump when it is acting up (I need to figure out a rig to do this. All connections are threaded after the fuel pump).
Any initial thoughts?
First off let me say I really have found these forums helpful in the past, but I am having issues finding the problem I am having. I feel like this should not make a difference, but both times this happened this weekend, I had the lower unit fully tilted up while on a beach, then lowered before starting (at least that is what I recall).
I will get the engine serial number but it is pouring rain right now and I don't know when it will stop. Engine is an early 2000's MerCruiser 5.0L EFI, ECM is a version 3/4 type. Lower unit is an Alpha 1.47R with the serial number of 0L946190.
Both times this happened I had been pulling people tubing so the engine had been running fairly hard. I pull up to shore, shut the engine off, then pull up the lower unit all the way. Get ready to take the next person out and as soon as we get away from shore, the engine starts fluctuating RPMs from 700 to 2000 a couple times then dies.
I would crank it and then it would start a couple times then die immediately after, then it felt like no amount of cranking could get the motor to start again. Every time I turn the key to run or the engine dies I can hear the fuel pump run for a couple seconds then stop. The pump does sound rather odd like it has a bunch of air in it or something. It certainly was not a smooth sounding pump (I am not sure how these act normally). Both times this situation happened I would try cranking off and on for 10 minutes then give up. I let it sit for an hour and try cranking again. After another 10-15 minutes of cranking, the engine would start to sputter and fire, then die. Then after 5 minutes of that and trying to give it some gas every time I got the engine to sputter, it would finally fire back up and run normal with idling around 600 RPMs and I would have my full power band.
The second time this happened it was the exact same scenario where I had just taken someone tubing, lifted the lower unit up all the way to pull up to a beach, then leave and get all those troubles again.
Things I tried:
Taking off the flame arrester and observing the injectors I am seeing fuel delivered while cranking. I checked all the ECM connections and they all looked snug. I did notice the nuts holding the ECM in place were loose so I tightened those up. My cable going from the coil to the distributor looked fine and I am fairly sure I am getting spark as I could get the engine running well both times after the hassle.
Things I have not tried that I would like to:
Take off the fuel/water separator and see how much water is in it (when I fill with gas I put in a bottle of SeaFoam each time to help stabilize the fuel longer as I am not out every weekend). Once this is done if there is water in it can I reuse the filter after I dump it out and refill it with gas?
Take the fuel pump out and inspect for any oddities (Is this even possible? With the way it was sounding am I just looking at a new fuel pump?).
Check the pressure from the fuel pump when it is acting up (I need to figure out a rig to do this. All connections are threaded after the fuel pump).
Any initial thoughts?
