Smoke from exhaust - mercury 2013 outboard 4 stroke

[zach175]

I have a mercury 2013 150hp 4 stroke outboard on a pontoon and recently got the "guardian system" warning - took to mechanic and overheat error code so impeller was changed, thermostat was changed. took it out yesterday and now some white smoke coming out of exhaust. mechanic is closed over weekend so i can't call them until monday. boat runs good to normal speeds and no longer has the guardian bog down engage and beep.

just wondering if safe to drive over weekend - wasn't seeing the smoke before the impeller was changed. is there a burn in time or something for the impeller? not much knowledge on boat motors.

EDIT - not a large amount of smoke but definitely causes a small trail.

 

[roffey]

I not that knowledgeable on outboards but there is no burn in time for the impeller. I would suspect if it were the wrong impeller you would not get the housing on...

Question is what does it smell like, rubber or oil?

 

[zach175]

i didn't pay much attention to be honest - i'll have to see when i head back out to the boat later this weekend to look at it again.

 

[zach175]

didn't realize there was a mercury forum - will post there. thanks for help!

 

[roffey]

if the impeller is working you will see water coming out of the (pee) telltale, I think if you see water spraying out your impeller is good and maybe look for smoke problems else where?

 

[JimS123]

What color? Is it smoke or steam?

 

[zach175]

To update - had the impeller replaced a few days ago and thermostat as well as there was "overheat" error code throwing it into a guardian mode.

Went out today - motor runs fine now, smooth, quiet like before and no smoke when idling initially. ran it slowly from idle speed to max speed (warmed up good) and then when going from max speed down to idle quickly it starts to smoke. white smoke almost looks like steam. and it is accompanied by water coming out of exhaust in spurts.

i put my hand on the smoke - barely any odor whatsoever - maybe slight hint of gasoline but otherwise not really odorous at all and no oily / residue on my hand after.

i then tested and went from max speed slowly down to an idle when parking the boat and no significant smoke when doing this.

only seems to happen when going from fast to slow or medium to slow really fast. can't see it when not in idle either - have to be in idle to see a significant amount of smoke.

i read mercury will cool themselves by throwing water through exhaust but that's not a completely normal scenario right? could thermostat be screwed up? supposedly it was just replaced friday w/ the impeller.

i'm going to call my mechanic on monday as well but appreciate any input over the wekeend!

 

[zach175]

telltale always has good stream, no issues it seems w/ that.

 

[roffey]

My 2 cents are if the telltale is good then your impeller is fine. I'm betting all is good, your just noticing it now because you changed something and it likely did this all along.