2009 mercury 4 stroke bogging sometimes

georgia088

Cadet
Joined
Aug 14, 2017
Messages
29
I’ve had a mercury elpt 90 4 stroke for about 6 months. About 3 months after getting it, I was running WOT to get out of a storm. All of a sudden it bogged way down like it was going to go dead or running out of fuel. Then it surged back up and back down. Over and over. I could turn it off and it would crank back up and idle with no problem.
I thought maybe bad gas. Drained the gas and changed the fuel filters. Fuel filters did not look bad at all, but I changed anyway. This seemed to fix the issue.
Yesterday. It started doing it again…. It will run fine for a few minutes at any rpm and then start bogging like it is going dead and surging. I can quickly turn the ignition off and crank back up (boat still moving from momentum) and take off and it will run fine again for 30 seconds/ Minute…

any ideas? Bad coil? Overheating?

I’m at a loss!
Thanks!
 

pointblank1000

Petty Officer 2nd Class
Joined
Jan 17, 2011
Messages
139
How old is the fuel pump?
You can crack it open and see the condition of the diaphragm.
 

papspontoon

Cadet
Joined
Aug 18, 2021
Messages
22
This is a four stroke. Does it have a fuel pump that has a diaphragm? I thought they had electric fuel pumps.
Thanks!
My four stroke has two fuel pumps. A mechanical lower pressure that fills the VST where the high pressure electric pump is located
 
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