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RHuff

Really, Really Stupid Question

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When you guys start your motors and let them warm up on idle, do you trim your motor as far down as it will go, or do you trim it to level? I've always just trimmed it to where I thought it was level. Thing sometimes has a hard time starting (2008 Mercury 50HP 2-Stroke), but runs great after it gets warmed up. Yesterday, I trimmed it as far down as it will go (slightly past level) and the thing started on the first turn and idled great and warmed up much quicker. Have I been depriving it of gas by not tilting it all the way down? 

 

Also, I've always ran mid-grade gas in it (89 octane) I believe and added the green colored marine 360 sta-bil to it. I have a quarter of a tank of gas left. I think I'm gonna add a full can of seafoam, run it on idle for a while to clean it out, and then syphon the remaining gas in and put ethanol free gas in it from now. 

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Normally, if it's a carbureted motor, you want to trim the level, that was actually critical on the old 92 - 95 V6 OMC's. The carbs on those motors a basically junk.   When the motor is trimmed off level it screws the float level up and some motors just don't like that, especially if it's one the level is not properly to start with.  Plus it puts the motor a lot deeper in the water, increasing the back pressure which some motors are also picky about.  Fuel injected motors are not quite as picky as carb motors other than those sensitive to the increased back pressure.

Now, with all that said, use what ever makes the motor the easiest to start and it idles smoothest.   Other than out of the water, that burns the water pump within seconds.

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I've got a 97 Evinrude 130. It starts and idles better when it's trimmed up to relieve the back pressure. Once it's been running and warmed up a little I can drop it down without much issue. You have a Mercury though which in my experience unless it's an EFI have always had more issues starting especially in that 50-60 range for whatever reason. 

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6 hours ago, RHuff said:

When you guys start your motors and let them warm up on idle, do you trim your motor as far down as it will go, or do you trim it to level? I've always just trimmed it to where I thought it was level. Thing sometimes has a hard time starting (2008 Mercury 50HP 2-Stroke), but runs great after it gets warmed up. Yesterday, I trimmed it as far down as it will go (slightly past level) and the thing started on the first turn and idled great and warmed up much quicker. Have I been depriving it of gas by not tilting it all the way down? 

 

Also, I've always ran mid-grade gas in it (89 octane) I believe and added the green colored marine 360 sta-bil to it. I have a quarter of a tank of gas left. I think I'm gonna add a full can of seafoam, run it on idle for a while to clean it out, and then syphon the remaining gas in and put ethanol free gas in it from now. 

Do yourself a favor and run premium 91 octane gasoline in your outboard engine. If the engine is hard starting, check or change the spark plugs first, electrodes should be tan not black that would indicate fouled and too rich fuel mixture.

As long as the water pick up under the cavitation plate is under water the trim should make little difference starting or warming up.

Tom

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I just warn about the seafoam. I put some in mine almost 2 weeks ago. After a week I have had some issues with it throwing small fits like it's caughing. I want to think it's the junk the seafoam broke loose getting blown out. But I have no idea if that is what is happening. It is the only thing different I have done to it though. Last trip was better much less fits. Just a note of caution. 

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Is it possible that it isn't related to the engine level?  Do you find it is more difficult to start if you haven't used the boat for a while?  If my outboard sits for two or three weeks I have to make sure I squeeze the primer bulb 20 - 30 times if I want it to start right up.

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Always run 91 octane.  Here in CA I've only used Chevron 91 and have not had any issues with any of my bass boats. (knock on wood)

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I've always hear not to run Premium. I certainly will if you guys think I should. Again, it is a 2008 Mercury 2-Stroke 50 HP..

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If you can find it, use Ethanol Free Premium.  Ethanol is what often causes problems when the outboard sits there for a long period of time so if you can put gas in there that does not have ethanol, do it.  Same thing goes for the lawn mower, snow blower, and other small engines.

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If you listen to the manufactures and engineers that design them, they tell you to only run the recommended octane fuel.  Higher octane fuels burn slower and cause and increase in carbon fouling and decrease in performance. 

If you listen to the internet, they are apt to have running 107 octane racing fuel.  It's just a matter of where you put your trust.  The best is not always the best.

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Agreed on the octane (don't run high octane unless manufacturer recommended) and also definitely the ethanol free gasoline. Especially for older motors.

Higher octane gas is only important for high compression motors or forced induction where detonation is a concern. You use the high octane fuel so that you can push the limit higher. On any other motor it's just wasted money for less performance. BUT, some premiums or even mid-grades will actually state that they are ethanol free, which (especially if a top grade fuel like Chevron/Shell/Exxon etc) would be my choice.

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I always use ethanol free gas that a station nearby carries. I also use Stabil every time I fill up, that way if I get hurt or something and can't use my boat the gas won't go bad. 

I was old gas starts going bad in about s week, so I put Stabil in right away. 

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My 2hp Yamaha 2 stroke always starts on the first pull.. those big boys are a pian in the ass at times and their to heavy for my canoe. Happy Motoring!

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