OMC/Yamaha 4.3 V6 200 issues (2 stroke)

[99yam40]

If that is all you are looking for, cylinders not firing/powering throws things out of balance

[TownsendsFJR1300]

Does it run at WOT and if so, the RPM's?

Might want to look closely at your prop. Put a pointy edge adjacent
to one outer edge of one blade and compare it to the others.

Make sure it's NOT bent / warped, etc.

If its a looper, it's probably carbed. Drain the fuel from each float bowl,
should be a drain plug. Catch what comes out (and perhaps squeeze the primer bulb) to flush.

We're checking for debris / water, etc...

*Basic question- but how old is the fuel in the tank? Did you add new fuel to really old fuel? If so, that could very well be your issue.


This may help figuring put what you have: http://www.boats.net/parts/search/BR...SON/parts.html
(the CHARTS below)

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[Cpt_MotorBoat]

If that is all you are looking for, cylinders not firing/powering throws things out of balance

That was my first thought as well. But wouldn't that be out of balance the entire RPM range not just the mid level?

I was almost thinking maybe the oil/fuel didn't separate well and it was flooded with too much oil. But that would explain the smoke, but still not sure how that would create vibrations.

[Cpt_MotorBoat]

Does it run at WOT and if so, the RPM's?

Might want to look closely at your prop. Put a pointy edge adjacent
to one outer edge of one blade and compare it to the others.

Make sure it's NOT bent / warped, etc.

If its a looper, it's probably carbed. Drain the fuel from each float bowl,
should be a drain plug. Catch what comes out (and perhaps squeeze the primer bulb) to flush.

We're checking for debris / water, etc...

*Basic question- but how old is the fuel in the tank? Did you add new fuel to really old fuel? If so, that could very well be your issue.


This may help figuring put what you have: Johnson Outboard Parts
(the CHARTS below)

.

Haven't been WOT just yet. Conditions were a tad too rough to WOT but 3/4 throttle was about 4,000 RPM..

The gibration was around 3k ish.

As for the fuel, the tank was a little empty when I bought it. Maybe 1/8th tank. But I'm not sure how old/long that fuel was in there. But I did fill it to 3/4 tank. So that could very well be it.

I've got a trip this weekend so I won't be able to tear it apart today or tomorrow but after I will def take a good look at the cars and bowls. That does make sense.

Prop looks fine tho. I spin and look at it every time I wash the boat and take it out to make sure it's not in gear and look for damage and wear

[TownsendsFJR1300]

re-reading your first post, quote:

" She wanted to cold start on the "Run" setting on the fuel primer rather than the "Start up" setting.

She smoked a good bit which was semi normal but it was a little longer than normal and she seemed to run a little bit rough." End quote.


That sounds like she's running rich, very possibly a stuck carb float (open).

That would cause rough running, help the engine start when cold.

Pull your spark plugs and see what they look like... I suspect one will be darker/wetter than the rest. That'll narrow down if it's a carb issue and which one..

Wouldn't be a bad idea to clean all the carbs anyway as you don't know the history, (old fuel, ethanol fuel, un-stabilized fuel).