I've a 2 1/2 year old Tohatsu 8HP 4-stroke that is running a little rough. It's got 100 or so hours on it and has been properly winterized (fogged, plugs, oil) as necessary. Here's the rub - it seems to be burning oil - exhaust is a little smokey. I also noticed yesterday it spit trace amounts of oil into the water at re-start up. It'd run for 20 minutes or so, we shut it down to flush it and restarted when I noticed the oil spit. What is up? Any ideas?
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Need more info
Sounds like you were doing decommissioning maintenance what with flushing and all. Prior to the smoke, had you removed the engine from its mounting and layed it on its side? I know on Yamaha 4 strokes they can only be layed on one side not the other or they will foul the combustion chambers and thusly the spark plugs with oil and run rough and miss-fire and spit oil out of the exhaust. Hmmm, that's what yours is doing,,,,,
Sounds like you were doing decommissioning maintenance what with flushing and all. Prior to the smoke, had you removed the engine from its mounting and layed it on its side? I know on Yamaha 4 strokes they can only be layed on one side not the other or they will foul the combustion chambers and thusly the spark plugs with oil and run rough and miss-fire and spit oil out of the exhaust. Hmmm, that's what yours is doing,,,,,
Nope
Not decommissioning, just routine flushing after use. It's not super-smokey, exhaustwise, just more than seams normal. Motors been on the transom since April. Hear what you are saying about laying it over though -did that once- forget about starting at all - had to pull the plugs and pull the starter cable over and over till all the oil got out! What a mess. Anyhoo, just not sure what is up with it now. Maybe 'nuttin?
Not decommissioning, just routine flushing after use. It's not super-smokey, exhaustwise, just more than seams normal. Motors been on the transom since April. Hear what you are saying about laying it over though -did that once- forget about starting at all - had to pull the plugs and pull the starter cable over and over till all the oil got out! What a mess. Anyhoo, just not sure what is up with it now. Maybe 'nuttin?
Maybe, but,
Pull the plugs and read them. Those are your window to almost anything going on inside your engine. You want 'new' looking plugs with that little run time. If you don't know what you're seeing (assuming they don't look new) take them to an auto parts store and ask to see their sparkplug diagnostics chart. But most guys working in those places don't need a chart.
Pull the plugs and read them. Those are your window to almost anything going on inside your engine. You want 'new' looking plugs with that little run time. If you don't know what you're seeing (assuming they don't look new) take them to an auto parts store and ask to see their sparkplug diagnostics chart. But most guys working in those places don't need a chart.
Just had FedEX deliver Tohatsu 9.8 4 stroke today-
This is not the type of thread I wanted to read. Please fix the problem, and may it be a simple fix. Oh, don't forget to post how easily you fixed the problem. abe
This is not the type of thread I wanted to read. Please fix the problem, and may it be a simple fix. Oh, don't forget to post how easily you fixed the problem. abe
Abe,
I'll do my best. The motor has never let me down, just not acting its usual self. I'll pull the boat for the season in a week or two, take the plugs down to the parts store (thanks Fred for the tip)and let you know what gives. Like I said, it's never failed me (knock on wood), just want to treat her right.
I'll do my best. The motor has never let me down, just not acting its usual self. I'll pull the boat for the season in a week or two, take the plugs down to the parts store (thanks Fred for the tip)and let you know what gives. Like I said, it's never failed me (knock on wood), just want to treat her right.
Change plugs and oil
Different engines have greater, or lesser, resistance to fouling. Not just oil fouling. You can gas foul a plug as well. The additives in the gas burn onto the conductor and electrode, and often, will not burn off. In fact, on a high performance rotary engine, I've found you can't even sand them off. Of course I discovered this at ten below zero in Milwaukee one winter. Threw in a new set of plugs and it couldn't wait to start! Sounds like you fouled a plug, maybe from long idling?, and you're now getting poor combustion. It wouldn't hurt to change your fuel filter either. Restricted fuel supply can affect fuel/air ratio. Inefficient combustion will cause smoking. Also, do not use gasoline with ethanol or any other eco-friendly blends. Lots of info floating around on their negative (read expensive) effects on marine engines not designed for them.
Different engines have greater, or lesser, resistance to fouling. Not just oil fouling. You can gas foul a plug as well. The additives in the gas burn onto the conductor and electrode, and often, will not burn off. In fact, on a high performance rotary engine, I've found you can't even sand them off. Of course I discovered this at ten below zero in Milwaukee one winter. Threw in a new set of plugs and it couldn't wait to start! Sounds like you fouled a plug, maybe from long idling?, and you're now getting poor combustion. It wouldn't hurt to change your fuel filter either. Restricted fuel supply can affect fuel/air ratio. Inefficient combustion will cause smoking. Also, do not use gasoline with ethanol or any other eco-friendly blends. Lots of info floating around on their negative (read expensive) effects on marine engines not designed for them.
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