Logo
FULL SITE MENU

2016 Mercury 25HP EFI Will not start when hot

D

Drewbe77556

New member
I have a 2016 Mercury 25HP electronic fuel injected motor that will start right away when cold but after running the motor for an hour or so and stop to fish. When I go to start the motor back up, it will crank but will
not start. After waiting an hour or so, it will start and run with no issue. I don’t even know where to start. Thank for any help.
 
I’m planning to take it out tomorrow with tools in hopes that the issue happens. I have changed the fuel filter and was thinking of cleaning the VST before taking it out. It almost seems like it vapor locks.
 
It would not start again today after warming the motor up. Ran the motor for about 30 mins, stopped for about 20 mins, motor started fine, started going and it started spitting and spuddering, shut off and would not start back up. I checked the fire on all 3 spark plugs with an in line spark tester and all 3 were firing. I drained the VST, pump the fuel line and it started back up. When I got home I took the VST off and opened it up. Very little was on the screen on the bottom. Not sure what else I should check.
 
Check you charging voltage and ground to fuel pump. If loose or overcharging it will lock up due to heat. Draining VST,setting and fresh VST fuel refill likely cools it soi t starts again.
 
Has anybody ever figure out what causes this, starts fine cold, warms up and when you turn it off it will crank but will not start until cooling off. It will start warm with the pull cord.... confused
 
Mine will start fine at the dock (cold) run out to the fishing grounds warms up the engine, shut it off and will not re-start with the electric starter, pull the cord twice (?) and it will start. frustrated to say the least.
 
Never had any problems with my 2016 25hp efi. My suggestion, take your engine to a Murcury authorized dealer and explain what is going on.
 
I’m having the very same problem with mine. Start as soon as you turn the key and runs perfect but if you shut it off after it warms up, it will not start up again unless you let it sit for a few hours. Any ideas would be appreciated.
 
Naugus said:
I’m having the very same problem with mine. Start as soon as you turn the key and runs perfect but if you shut it off after it warms up, it will not start up again unless you let it sit for a few hours. Any ideas would be appreciated.
Click to expand...
I have the problem too. 2015 25hp EFI. Making sure the fuel tank cap is on properly (turn it til it clicks) and making sure the vent screw is loosened in the top of the cap helps some but doesn't completely prevent the problem. I ordered a new fuel cap with the vent ring that goes under it. Waiting for it to arrive to see if it helps.
 
I am also having the exact problem with my 2020 25hp EFI. I have pulled the fuel pump and bench tested it and it is running fine. 0.5 amp draw with no load and sounds fine. I have read on other posts that it could be an ECU issue. Not sure how to test that. Very confusing issue. Motor runs fantastic while running. Shut it down after 20-30 minutes of running and it will not start for an hour or so. I have not pulled the cover yet to see if or how hot the ECU is after the 30 minute run time. That will be my next step. Any help would be greatly appreciated.
 
Back
Top