2000 Johnson 150 OceanPro Check Engine Light Model J150VXSSS

[cweaver22]

Every time i take my boat out it will run great with no check engine light coming on for an hour or two. Then intermittently the check engine light will sound and then eventually go off. The engine runs fine and doesn't seem to change its behavior in anyway when the sound alarms. It happens at higher RPMs as well as lower RPMs. It seems to go off more frequently once it starts happening. its been happening for 3 years now and its driving me nuts!

Things i've done:
Replaced fuel tank and check valve (not for this issue, it had a hole in it)
Replaced fuel filter
Replaced all fuel lines leading up to the engine
Replaced fuel primer bulb
Replaced thermostats
Replaced water pump
Added a fuel filter and water separator
Replaced VRO

I also just installed a new Tachometer with Johnson System Check, but i haven't tested to see if that impacts it in anyway yet.
Additionally i have a 3 gallon gas tank i was going to try and hook up to rule out any tank or check valve issues.

What else could it be? Or what else could i try to replace to fix this check engine light?

[AndrewM-Fishing]

The "Check Engine" fuel restriction set off by a vacuum sensor next to the pump. Check for shorts to ground. Sensor could be failing.

[cweaver22]

ok thank you i just ordered a new sensor. interestingly enough when i went to look at the vacuum sensor its missing the plastic nut that holds it in place, i wonder if the fact that its just flopping around could be enough to set it off intermittently?

[ChampioNman]

It's more of a wave washer than an actual nut. Check your high speed orifices and make the are fully secure in their seats in the float bowl.s,

[cweaver22]

It's more of a wave washer than an actual nut. Check your high speed orifices and make the are fully secure in their seats in the float bowl.s,

Do you mean the high speed orifices in the carb? If so i'm thinking that is not the issue as the light comes on at both high speed and low speed. i guess they both could be out of wack. Do you have any references on how to do this?

[ChampioNman]

Yes, remove the carb bowl drain plugs and insert a small straight blade screwdriver into the opening and see if they are all secure in their bowls.

[cweaver22]

UPDATE: Since purchasing the boat i've added a Fuel/Water separator with a filter, an inline Fuel Flow Sensor for my Simrad MFD and i've replaced the fuel tank due to a leak in the old one. I'm not sure if the old tank had a check valve but i know for sure that the new one did. I've since removed the check valve and bypassed the fuel/water separator, and fuel flow sensor. I've taken it out twice now and run about 25 gallons of gas through it with no issue, no check engine line and no alarm at all. I will continue to run it like this and after this year if still no alarms, i'll try adding back in the fuel flow sensor and the check valve to try and determine which one was causing the issue. my guess is the check valve, but i'll report back.

[Bassmeister]

Those fuel flow sensors have been known to cause a restriction.....I would connect one at a time back up and run her before connecting the other.....leave the fuel flow sensor for last.....JMHO