Please Help! 150hp Mercury XR6 is Running horribly

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KDUB10

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May 16, 2010
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Ok so i just bought a nitro bass boat with a 150hp Mercury engine on it. Its a 1999 outboard, i put some seafoam in the gas and went fishing today and it hasnt seemed to help at all with the boats hard starts, and the motor almost bogs down completely when you redline the throttle. When you try to max out the gas the motor begins to run inconsistently, eventually you have to come to a complete stop to gain control of the throttle again. Also it seems to run a little rough at an idle even, and sometimes stalls out at idle as well.

Please any help is appreciated!

thank you
 
J

Jacket4life

Petty Officer 1st Class
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Apr 22, 2010
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Re: Please Help! 150hp Mercury XR6 is Running horribly

When is the last time you replaced the plugs? They are cheap and solve a LOT of problems on any internal combustion engine.
 
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BRIdaho

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Re: Please Help! 150hp Mercury XR6 is Running horribly

Ive had some similar problems with and older 150 V6 Mercury. 1979 to be exact. After replacing spark plugs, all fuel lines, adding a fuel filtering system, and flushing fuel tanks I still had this rough running hard starting problem. I purchased a SELOC manuel and started checking electical systems. I found one leg on my stator was bad and both CDI boxes were bad. Ater replacing all three components... It runs like a champ and starts great!!! It now starts within 10 - 15 seconds of cranking.....Not a cheep fix though... Good luck...

BR
Blackfoot, Idaho
 
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dave2092

Seaman
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May 9, 2010
Messages
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Re: Please Help! 150hp Mercury XR6 is Running horribly

I had same problem with mine 1993 merc xr6. changed fuel lines bulb, filter, plugs, cleaned carbs, check all oil water lines for signs of leaking. I had a major oil leak on oil line by transom which made it run super rich, also had a pin hole leak in small water hose. just fixed oil lines today let u know how it runs next time I take it out.
 
j_martin

j_martin

Admiral
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Sep 22, 2006
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7,474
Re: Please Help! 150hp Mercury XR6 is Running horribly

Your first post, and so far you got 3 newbies telling you about their boats. Tough luck I guess.

You just bought a high performance boat and engine, threw a 7 dollar can of well advertised fuel additive at it, and it runs bad. We ain't magicians, but we can help. You will have to do some grunt work to get to the bottom of it.

First is compression. This is to verify the integrity of the engine. If it has a fuel shortage problem, and has been run much as you described, it is probably well past due for an complete overhaul. If you luck out and the numbers are good, then it's worthwhile to proceed, otherwise nothing you can do in the tune up department will help at all, and will be wasted time and money.

Next you verify spark, then fuel. We can guide you through that.

Then comes the synchronization and timing adjustments.

Do yourself a favor. Don't try to run it like that, and get a genuine Mercury maintenance manual for it.

hope it helps
john
 
K

KDUB10

Cadet
Joined
May 16, 2010
Messages
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Re: Please Help! 150hp Mercury XR6 is Running horribly

Thanks for all the suggestions guys! I'm going to give all of this a try and I just actually bought all new spark plugs as well. Hopefully I'll be able to get to the bottom of it and get it going well
 
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Hackamore

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May 14, 2010
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Re: Please Help! 150hp Mercury XR6 is Running horribly

I am pretty new here but have ran outboard motors for some odd 60 years. I hear all these people that buy a boat without even trying it out. My suggestionm to anyone planing on buying a boat and motor of any kind to have the seller put it on the lake and take you for a ride in it. Even let you drive and run it. If he is not comfortable with then tell him so long sucker, and walk away. So many times when they are not comfortable with not wanting to let you try it out, they know something is really wrong with it. Example I just bought a 1989 Skeeter SK2000 with a 225 Super mag Mariner motor and the gentle pulled it all the way from Kilgore to Azle which is about 85 miles and we had a great time in it. He knew his boat and wanted it to be right. FYI that is all this is.
 
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dave2092

Seaman
Joined
May 9, 2010
Messages
50
Re: Please Help! 150hp Mercury XR6 is Running horribly

whats with the newbie crack. just because we are new to this site doesnt meen that we can not give info. some of us just have the same outboard with some of the same problems and just wanted to let him know what we did to fix our problem. I'm sorry maybe if we had 9000 posts like you that would make our advise better.:( Me I would rather be fishin than sit on the computer typing all day.
 
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CaptainHook

Petty Officer 1st Class
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Mar 18, 2010
Messages
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Re: Please Help! 150hp Mercury XR6 is Running horribly

ONe way or another, let us know how you make out!!! Welcome aboard!!!
 
K

KDUB10

Cadet
Joined
May 16, 2010
Messages
14
Re: Please Help! 150hp Mercury XR6 is Running horribly

Will do , Thanks to everyone for the help! I replaced all my spark plugs and replaced the old fuel line from the tank to the outboard, including a new primer bulb. I started the boat with the muffs and it seemed to run much better, started better, the idle was much more consistent, so maybe that will do it. Im sure ill have it out on the lake for some fishing this weekend so ill be sure to update. Thanks to everyone again, the help is much appreciated.
 
K

KDUB10

Cadet
Joined
May 16, 2010
Messages
14
Re: Please Help! 150hp Mercury XR6 is Running horribly

alrite, i took the boat out and it ran perfect the first day, then the second day which was today it seemed to stall out on an idle, and also started hard again. It is running perfect on the top end at high speed, could i be fouling plugs? if so what would cause the plugs to foul out? when it starts hard after a couple or turns of the key you can smell gas as well so i dont know if it is somehow flooding itself? any suggestions once again are appreciated.
 
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