Smoke from Yamaha F150

Mr_Shamrock

Petty Officer 2nd Class
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Oct 8, 2009
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This past Saturday we took the boat out and I noticed that we got a decent puff of smoke at start and it continued to lightly smoke for about 15 seconds or so. It has never done this before. It smelled like oil burning. I am wondering if our previous trip (the Sunday before last) could have had anything to do with it. We got caught in a pretty bad storm that tossed our 22 foot pontoon around like a toy. It actually got a little scary there for a few moments. Is it possible this had anything to do with it. Also, and this is the strange thing, I check the oil the night before each boating day and it has always been right on. I checked it yesterday and the oil level is about 1/8 of an inch over the full mark. I know this sounds strange, but I saw with my own 2 eyes. Any ideas? If it matters the motor is a 2007 F150. Thanks in advance!
 

rodbolt

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Re: Smoke from Yamaha F150

when the boat is stored what trim angle is the engine left in?
what is the WOT RPM with the load you had?
 

Mr_Shamrock

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Re: Smoke from Yamaha F150

It is stored with the motor all the way down. WOT is under the motors max I believe somewhere around 5000 RPM, but we did ride WOT for about a 10 minute run to meet some people at a campground. This very unusual for us as most of the time we are under 4000 RPM usually way under just idling around site seeing. Actually that is the hardest it has ever been run. Could that 10 minute blast have something to do with it?
 

rodbolt

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Re: Smoke from Yamaha F150

for the trim angle, smoke is normal.
fix the overproped issue and the making oil goes away.
 

Mr_Shamrock

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Re: Smoke from Yamaha F150

Can you explain a little more please? Thanks!
 

rodbolt

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Re: Smoke from Yamaha F150

yes.
when run then stored in the full down position the spark plug end of the cylinder is lower than the crankshaft end.
gravity causes oil to head for the sperk plug end and over time a small amount will collect in the combustion chamber.
causes a small amount of smoke n start up.
if that motor cannot turn 5700 to 6000 RPM with that days load it tnds to "make" oil.
this is fuel blowby past the rings.
typically there are two causes,overproped for the load or the thermostat is stuck open.
a bad fuel pump diaphram or a leaking VST needle can cause it as well but usually you will have running issues.
 

Mr_Shamrock

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Re: Smoke from Yamaha F150

Thanks! So should the motor be stores at a level position? I always thought it should be stored down so water will run out and to take the load off the hydraulics. I will have to do the research on a new prop - I guess I was just more concerned with over reving it more than overproping it. This is still the prop that the boat came with new. The hard part is sometimes it's just me and the wife and sometimes we have 8 or 9 people plus all their gear on board. With just me and the wife the boat gets real close to 5500 and will do around 30-35 MPH with it loaded down like it was that day it will only do 25 MPH this is according to the GPS I don't have a speedometer.
If I am getting a little fuel in the oil should I change the oil more frequently. The motor is still under warranty so if it needs something done I want to get it done and learn for future reference when the warranty expires.
This is my first 4 stroke outboard so I am still learning and I appreciate all your input. Besides this little situation the motor has been fantastic! Super quiet too!
 

rodbolt

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Re: Smoke from Yamaha F150

good engines, I own one myself.
but with the load THAT day it MUST be able to hit 5700 RPM, the rev limiter will grab you about 6100 RPM.
leave it trimmed up for 10 min or so after use then trim it full down.
 

Mr_Shamrock

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Re: Smoke from Yamaha F150

rodbolt - You were right on the money with the smoke thing. I was down at the dealer today picking up a part that mother nature broke and the mechanic was behind the parts counter. I asked him the same question, not that I was doubting your answer, and he said the same thing about the trim angle. He said he has had a ton of people ask about that and it is perfectly normal and won't harm a thing. Thinking back to the day in question, a friend came boating with us and was going to warm the motor up while I parked the truck. He trimmed the motor all the way completely down (which I always just get it level or a little higher when leaving the dock) and it sat like that for a few minutes while I hiked it from the parking lot. He didn't start it, because it was in gear and he didn't realize it. Anyway, according to the mechanic, that full down position will allow a little oil to get on top of the piston and of course it burns it off upon starting. Thanks for the information!
 

rodbolt

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Re: Smoke from Yamaha F150

no worries.
glad to see another competent tech.
 

Mr_Shamrock

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Re: Smoke from Yamaha F150

rodbolt, took your advice on the trim angle and had no smoke on start up Saturday. You the man!
 
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