Surging

BBetthauser

Cadet
Joined
Jul 19, 2016
Messages
6
I have a 1995 four winns with a 5.0 cobra and omc drive. I think I had gotten some bad fuel. Ran great the first 2 times out then I fueled up (premium) as always but a different gas station. It ran and got up to speed and planned out. After about an hour it started surging real bad and couldn't get pass half throttle or uip to plane. I checked the water fuel separator and it was full. I got it home and drained the tank. Since then have changed plugs, wires, cleaned the filters and replaced them. Topped it off and added sea foam as I typically do every few tanks of fuel. Took it to the shop and had it gone through and they had gotten it up on plane as well and seemed to work fine they said. When I got it back last week I took it out and the same thing happened with the surging. But once the engine had warmed up after trying to feather it up it started to come out of it and slowly started coming back to life. Maybe water is still in the system? Or have anyone out there had similar issues or have any tips or ideas to help me out. Thanks
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,401
Might be just coincidence after the fill up, don't know. If you pull the filter off and pour into a baggie or glass container to see if there is anything in there but clean gas. Did you replace the filter/screen in the carb?

Opinion comment:
I wouldn't put naphtha, isopropyl alcohol and machine oil in a gas tank, seafoam
Premium fuel will cost you more but will not improve performance
 

BBetthauser

Cadet
Joined
Jul 19, 2016
Messages
6
I pulled the water fuel separator and was full and drained the tank. The fuel didn't smell or look right. I have only run sea foam through it with premium fuel. I have cleaned the carb filter as well. It smells like it's running rich on fuel. Wonder if it's a air mixture issue. Possibly mass air flow sensor? Thank you
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,561
Stop using the SeaFoam.

Run it on a portable tank and see if it has the same issues.

How old is the fuel? The filter was full? What was it full of? You didn't screw the old filter back on did you?
 

BBetthauser

Cadet
Joined
Jul 19, 2016
Messages
6
It was full of fuel but discolored and seemed to not have the odor of straight gas, I stopped using sea foam. I ha e replaced the filter 3 times with new . I will try my portable tank off my flat bottom and see what I can find out. Thank you
 
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