Carbed Oceanpro burned piston (2nd one)

billdz10

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I have a 2000 OceanPro 250. Last season I burned #5 and needed a new powerhead. The mechanic rebuilt the carb on that cylinder, updated the needles on the others. The motor ran flawlessly for 100 hrs and now has burned #1 around the edges. In both cases no alarms, no warning just lost RPMS and that was it. I suspect a lean condition , possibly ethanol related. Anyone else seen issue like this will crossflow carbed 2 strokes ? I'm debating not fixing the motor even though its an almost new powerhead if I can't some up with some valid reason why this happened again
 

tx1961whaler

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Re: Carbed Oceanpro burned piston (2nd one)

Do you have a good filter/fuel-water separator on the fuel line(s) ?
 

Chris1956

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Re: Carbed Oceanpro burned piston (2nd one)

Normally an overheat condition, over advanced ign timing or dirty carbs (lean running) (or some combination of all three)will cause that piston and cylinder damage. It sounds like you need to clean all carbs, replace thermostats and water pump and perform a link and synch after you repair cylinder. Actually your mechanic should have done this for you. You might want to get a better mechanic.

BTW - Isn't that motor a looper?
 

Faztbullet

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Re: Carbed Oceanpro burned piston (2nd one)

What does the tops of the pistons look like?? Are they dry?? A looper piston should have the same color(dark) across the piston and have a slight wet look to it, if not it is lean. If the rebuilt powerhead was bored are the cylinder over .030? If so jets should have went up 1-2 sizes, can you post picture of piston?
 

billdz10

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Re: Carbed Oceanpro burned piston (2nd one)

Some additional info to answer your questions and thanks for the input

1. It does have a Raycore in line as well as the stock OMC filter. strange thing is I get a beige sand like material in the inline, I suspect ethanol.

2. It may be a looper, not sure how to determine that.
3. All the other pistons were dark , not wet but very uniform in color.
I assume the linkage was reset during the rebuild, I know the timing was set back 2 degrees as a precaution. I don't think it was spark, from what I understand that usually burns the center not the edges. The other thing is I ran the boat for about 100 hrs no problems at all then it just let go.

This is a pic of the first piston, didn't take one of the new damage but it looked very similar. The powerhead came directly from OMC and not a local shop. Not sure if it was oversized pistons on not. Will have to wait until spring to get another pic.
 

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ezeke

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Re: Carbed Oceanpro burned piston (2nd one)

That looks like the cylinder was run lean and for a good while. You might want to personally verify the jets in the carburetor.

You could also have an air leak.
 

Faztbullet

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Re: Carbed Oceanpro burned piston (2nd one)

I agree... either really lean or preignition from timer base problem..
 

SparkieBoat

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Re: Carbed Oceanpro burned piston (2nd one)

why did you get a new powerhead?? thats a lot of $$$...seems like you could have replaced that bad cylinder and been up and going for a few hundred $$.. I would also like to know if the carb from the first burned piston is the SAME carb as in the second burned cylinder..guess only your mechanic would know that. sounds like you may have a carb with issues.
 

billdz10

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Re: Carbed Oceanpro burned piston (2nd one)

I had to buy a new powerhead because the piston put a hole in the block. The carbs were not moved, verified that so it seems 2 of the carbs did the same thing. I did index the flywheel and I didn't see anything funny with the ignition, at least at the time I checked it.
 

Silvertip

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Re: Carbed Oceanpro burned piston (2nd one)

Ahhh -- another blame it on ethanol problem. Damn, burn down a piston, fix that carb, not the others, and down the road a piston fed by any un-rebuilt carb burns down. Blame it on ethanol. Logic says it has nothing to do with ethanol. It is due to a carb that needed a rebuild just like the last time, or investigation of everything else related to lean running/ignition timing but not ethanol blended fuel.
 

ezeke

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Re: Carbed Oceanpro burned piston (2nd one)

It is doubtful that the fuel or the fuel pump is directly related to your problem because those causes would normally have damaged all of the cylinders or pistons.

Particulate problems in the fuel are related to fiberglass fuel tanks and not most plastic or aluminum tanks. Some much older fuel lines were not alcohol resistant and could degrade. Your redundant fuel filters should capture most particulate, but could contribute to fuel restriction.

If you have fiberglass tanks you may wish to consider the following information: http://www.boatus.com/Seaworthy/fueltest.asp
 

R.Johnson

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Re: Carbed Oceanpro burned piston (2nd one)

Has there ever been a fuel test run on this engine? By that, I mean fuel guality:water: fuel pressure, fuel vacuam?
 

CharlieB

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Re: Carbed Oceanpro burned piston (2nd one)

I have a 2000 OceanPro 250. Last season I burned #5 and needed a new powerhead. The mechanic rebuilt the carb on that cylinder, updated the needles on the others. The motor ran flawlessly for 100 hrs and now has burned #1 around the edges. ...................................................why this happened again


I think it is pretty clear.

Many shops will not even consider rebuilding only one carb.

NEVER, ever, rebuild or replace any powerhead without a COMPLETE fuel system rebuilt, ALL carbs cleaned WITH new kits, rebuilt fuel pump, NEW T-stats and NEW water pump kit.
 

billdz10

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Re: Carbed Oceanpro burned piston (2nd one)

I'm perfectly willing to accept the carb is the culprit here but is there any tell tale signs looking at it. Would it have a damages seals, needle, stuck float ? What causes a lean condition in a relatively simple carb ?
 

HybridMX6

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Re: Carbed Oceanpro burned piston (2nd one)

something as simple as crud built up in it from old fuel left in the bowls could have done it. Anything that could block the jet, even partially, would cause a problem. You will want to tear down every carb, being especially particular about the one that feeds the problem cylinder, and check for anything in the bowls, jets, or little passageways. Cleaning every orifice you can find, behind every welch plug, etc., is the only way to be certain there is nothing blocking it.
 

pine island fred

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Re: Carbed Oceanpro burned piston (2nd one)

Agree with the ideas of a carb. problem. Lean mixture can be caused by an air leak downstream of the carb. Also small trash in the jet or low float bowl level setting. Consider slightly larger jets in the carbs. or raise the float bowl settings slightly. FRED
 

SparkieBoat

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Re: Carbed Oceanpro burned piston (2nd one)

I would check all gaskets in the carb for air leaks..it does not take a very large piece of trash to obstruct the flow. I once had a small blop of oil form into an obstruction, I had let motor sit for about 3 weeks and used wal-mart oil, many people in here swear by Tech oil, but after that experience I switched to Pennzoil. I did not use any fuel additives like Sea Foam, which I use a lot now. Also make sure you got good clean filter/s. If you notice your motor is not performing as it should..shut it down and find out whats up. you can do a visual on the carbs easy enough, just take off the cowl and carb cover and look at the carbs while at half or WOT, you can tell if one has a different spray pattern, indicating it needs fixin.
 

Dhadley

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Re: Carbed Oceanpro burned piston (2nd one)

What spark plugs are you using?
 
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