2015 Mercruiser 4.3L TKS - Engine stall after 30 minutes; Unable to restart at 1/4 throttle

Paradise773

Recruit
Joined
Jul 24, 2022
Messages
2
Have had ongoing issues with my 2015 Mercruiser 4.3L TKS (carbureted) / Alpha 1 I/O. After running it for 30 minutes at 2000 a 3000 RPM on the lake, I head back to the dock, throttle back, and it dies. Can only restart it at 1/2 throttle+ but as soon as I cut the throttle to get it in gear, it dies again. Thermostat showed below 175 degrees. Unscrewed gas cap and did not hear a hiss.

Brought it into repair shop who spent “hours on it” and didn’t find any issues. They did not do a lake test despite my multiple requests. 😡

Is there a checklist of steps I should do to rule things out? I’m a newb to boating and boat engines.

Thanks in advance!
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
43,175
Having it at the shop I'll assume they had it running on a hose at idle and it did ok?

Need at least 1/2 throttle and later would idle, I would lean toward the carb was flooding. Might have had a spec of crud in the needle seat and it sitting for some time, it dislodged and starts working ok again.

Take the fuel filter off and pour contents into a clear container to see if there is anything but clean gas.
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
7,095
What do spark plugs look like ? Agree sounds fuel or carb related.When it happens look to see if fuel comes out of accelerator pump nozzles when throttle is pumped.
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,343
Based on info provided, fuel supply sounds like a likely culprit but would not rule out shifting system, mainly lower cable binding causing shift interrupt switch engagement incorrectly
 

Paradise773

Recruit
Joined
Jul 24, 2022
Messages
2
Having it at the shop I'll assume they had it running on a hose at idle and it did ok?

Need at least 1/2 throttle and later would idle, I would lean toward the carb was flooding. Might have had a spec of crud in the needle seat and it sitting for some time, it dislodged and starts working ok again.

Take the fuel filter off and pour contents into a clear container to see if there is anything but clean gas.

That’s correct. They had no issues running it on hose and muffs. Will take a look at fuel filter. Thanks
 
Top