Blue Needs Help!

[THEFERMANATOR]

Welcome to E-10 fuels, it's a double whammy. Not only do you get reduced milage and power, you also get to deal with more deposits because of the cleaning effect of ethanol. It sounds strange, but ethanol likes to pick up any deposits and redeposit them where you don't want them. STAR-TRON is supposed to have an additve designed just for ethanol blended fuels.

[Blue_Runner]

I just read up on the Star Tron product. Sounds pretty good.

[willy]

Blue Man did you happen to notice the fuel primer bulb when this was happening, some of what you are saying are problems I had with diffrent motors over the years and they traced back to one, fuel bulb, even a new one cause they are all crap now, two, fuel pump on the side of the engine.
If not those and the plug pull does not reveal any issues in one or more cylinders time to run an auxilliary tank.
Also a good run like you had last week in some rough water can combine with the ethanol crap in your gas to dislodge a lot of sheeeet in your tank and lines, check your in line filter and the fuel/water seperator, you are likely to find unidentifiable sheeet in one or both of them.

[willy]

Oh yea one more thing, when was the last time you gave that puppy a decarbing of the cylinders?
Carbed up cylinders cause all kinds of sheeet, over heating, timing issues believe it or not, due to uneven compression and detonation along with reduced flow of the exhaust and intake, the cylinders never carb up evenly.
Thats all I got for now Dawg

[Blue_Runner]

Changed plugs, check. Cleaned all filters, check. Ran on auxillary tank, check...none of which fixed the problem. Time to

This is a bunch of I am supposed to be fishing for the next 2 weekends!!

[Blue_Runner]

When I get home I'm going to pull the new plugs and check it out good to see if I can tell if there is a cylinder not firing. If I can't tell I'm going to put the old-new plugs back in and do a decarb session, then put the new-new plugs back in. If that does not fix it I'm going to use my 9.9hp the rest of the year!! Not really, but that is what I feel like doing.

Will update when I know more. Thanks to everyone!

[Mulv80]

Next step for me would be a carb rebuild. Its not that difficult as long as you have the FACTORY repair manual. I'm betting you have some debris floating around in your carb bowls. I'm not sure about Yamaha but you may have a screw at the bottom of each bowl that you can loosen and let them drain and shoot some carb cleaner through. Its not the right way to do it but it may work.

[THEFERMANATOR]

Well BLUE, your YAMAHA uses the old style OMC carbs(the ones they copied off of OMC back when they first started building them). They do have adjustable idle circuits in them, but the mid and high's are fixed. There are 6 bowl drains you can pull out, and I would reccomend you do this before you take it to somebody. You can look up diagrams and parts here.

http://www.yamaha-motor.com/outboard/parts/home.aspx

[Blue_Runner]

Ferm, thanks bro!

Here is a little more info. The boat idles and runs great. No funny noises, stalling sputtering or anything like that. The ONLY thing that is wrong is it won't reach full RPM's (off by 500) and you can tell it is sluggish. It will consistently will make 4500 RPMS and 34 mph trimmed up sucking ducks as Reel would say. No variation whatsoever.

I just talked to a local shop and of course he's 2 weeks behind and he says my symptoms do not sound like carbs....said it sounds more ignition based and that I might be dropping a cylinder. If that is the case then what am I looking at here? Stator? Do these mamajamas have powerpacks? What else? When I check the plugs it should be obvious if one is not firing as the plugs I just installed are brand spanking new.

P.S. The shop said a ballpark figure on a carb rebuild is $150 per carb - OUCH!

Thanks!
Blue

[THEFERMANATOR]

That engine uses the YAMAHA CDI unit, and they are VERY reliable. A piece of trash sitting in front of one of your main jets would cause ALL of the issues you describe. Drain the carb bowls and look for debris. While you have the drain screws out, spray some carb cleaner in there. The main jets are located right behind the bowl drains, and they can be removed with the bowl drains out. Another thing you can try is to take it out and one at a time pull a plug wire off until you find the cylinder that doesn't change with the plug wire being off.