Bad Gas/Old Gas

dgarland10dgarland10 Posts: 17 Baller
This weekend I got out on the boat for the first time in 3 months. My boat always runs at 160 degrees usually and doesnt put out much smoke in the exhaust. Boat fired right up but about 20-30 minutes in noticed the temp was up to about 170/175, but water was coming out and the exhaust seemed to have more smoke than normal and smelled a little differently. I watched for a bit to make sure temp didnt go up and that water was still cycling through, and eventually temp went back to 160 and exhaust seemed more normal. My question is could old or bad gas cause this smoke and temp increase?



  • LeonLLeonL Posts: 2,259 Crazy Baller
    Not much chance of that. Gas only 3 months old? That's nothing. Don't know what happened, but you can pretty much be sure it ain't gas.
    Leon Leonard Stillwater Lake KY - SR Driver SR Judge
  • DWDW Posts: 1,863 Mega Baller
    @dgarland10 : Smoke won't be from the fuel. Blue smoke will be oil burn, white smoke will be water vapor or water in the combustion chamber. Temp increase probably due to less water flow through system, perhaps simply due to raw water pump needing a good prime, worn out impeller or slow opening thermostat since temps returned to normal, diagnosis would need more detail on operating conditions when engine was warmer (idle, high speed, load, etc).
  • MISkierMISkier Posts: 2,273 Mega Baller
    Water in the gas? Causing steam in the exhaust and extra heat?
    The worst slalom equipment I own is between my ears.
  • dgarland10dgarland10 Posts: 17 Baller
    OK, forgot to mention when I pulled the boat out I found a plastic bag stuck to the in the cover for the raw water pump, but not completely covering it, have no idea how long it was there, could that have caused the temp and smoke issue?
  • LeonLLeonL Posts: 2,259 Crazy Baller
    Temp, certainly. Smoke not sure. Water goes to the bottom and even with sloshing, water going through will cause misfire, cause it don't burn.
    Leon Leonard Stillwater Lake KY - SR Driver SR Judge
  • BraceMakerBraceMaker Posts: 2,904 Mega Baller
    Temp for sure.

    Your smoke thing sounds a bit like a fouled plug.

    My first step for any sort of smoke troubleshooting is to pull the plugs and inspect them. If all of them are the same that tells you something like maybe it had some junk in the injector and was dribbling fuel in and running rich and it cleaned up, which if it occurs again, or if it is intermittently bad like that you have something diagnostic probably in the fuel system, but also depending on the boat possibly a sensor - TBI indmar engines for instance will sometimes be hard to restart when hot due to a coolant temperature sender.

    But if one of the plugs is different, like steam cleaned that's usually a head gasket, or oily/wet that's usually bad spark like a dead or loose wire, gap too wide etc. etc.

    The bag may have driven up your temps causing it to change fuel map and then it shifted and let more water through and resolved itself, if it doesn't happen again.... I'd ignore it.
  • thagerthager Posts: 4,318 Mega Baller
    If water was just drained to winter proof the engine, your problem was an air bubble in the engine cooling system. Quite common, I have had this problem a few times. Usually a hose is letting air into the cooling system. Once water fully fills up problem goes away. White smoke is steam.
    Stir vigorously then leave!
  • Orlando76Orlando76 Posts: 779 Crazy Baller
    Without seeing the smoke I’d say water vapor. Any boat I’ve had did this when environment conditions were right.
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