High Vacuum / Burns Oil

Pistons look the same too me.Very hard to see with the lighting,but the left piston is slightly lower in the bore,and the right piston is way down there.Is that circle in the center of the dome some sort of casting mark?You can see it on all three pistons.Looks like the right piston is cleaner than the center&left piston,but hard to tell.Right one almost looks shiny.Also looks like the head gasket was on its way out.Look at the discoloration between the cylinders.Any more pics or damage to head?


     Mike

need to check the condition of the tips of the spark plugs also, the piston tops look different too, maybe it's just the lighting

need to look at the head and valve faces as well. nice hole thou. looks like it's been going for a long time. Notice how it's pitted in dish shaped on top of the piston. Pre-ignition over a long period of time?

Champion plugs right? don't think I would use those again.

Try this again

82 Nautique 1 wrote: If someone could let me know how to post pictures here I will post the best I could.

Thank Randy

Ok here's some of what I found out today.

Talked to shop that did the rebuild. Said any of the following could have caused this.

1. Run to lean
2. Clogged jets or inconsistent fuel to engine
3. Moisture or water in the gas
4. Leaking Gasket under Carb. Leaking manifold gasket, Leaking Head gasket
5. Timing to far advanced.

He also said that probably the only way for the octane booster to cause the problem was if it was not blended with the gas well. He highly doubted this was the cause.

He is willing to work with me on the problem. The motor was rebuilt in 2002, as I stated earlier less than 50 hrs on rebuild.

He suggested:

1. Checking the heads, pulling valves and etc. and preasure test them.
2. Checking all the pistons from the bottom side to see if the entire engine was hot
3. Check all the rings, replace as needed
4. Replace the obvious
5. Rebuild the carb
6. Pay special attention to the timing, advancing even 2 degrees could cause the problem.

In closing until we find out more I will pull the engine out and see what happens.

In talking to several people and reading the posts here there are many many areas that could cause my problem. But with the hole located directly in the center a detonation has certainly occurred.

I will report information as I receive it to let everyone that has showed interest how it comes out. If anything this may help some person in the future. I am sure this is not the first time this has happened to a marine engine in a Correct Craft boat.


If someone could let me know how to post pictures here I will post the best I could.

Thank you

ok no warrenty, no need to go back unless they going to do it again and install it too. If they installed it before then you might be able to get something out of them

ok it had 50 hr's since the rebuild how many days after the re-build is that?

how long and how many hours are on the re-build, is it out of warrenty?.

If it is a fresh rebuild it should be warrentied,

well,it should have had one, it doesn't know that you have taken it apart to figure it. WARRENTY VOIDED now, It should have been taken directly to who ever built the motor

straight and to the point no need to lead you any other way. But it sure sounds like you prefer the bullsh*t way instead,,, mickey mousing around with crap you don't need too. Find a good mechanic and let them fix it and be sure they re-jet the carb so it doesn't run lean anymore

ok then you burnt a hole in the piston then, so that means you have a lean running engine with a hotter plug than what the engine requires,then you add the octane boost, kids that don't know better and hell ride the motor all afternoon and never look at the temp gauge once. Not rocket science to figure out the motor is toast and how it happened. Most likely the block and heads can be salvaged, do this do that is a waiste of time now, pull it, completely rebuild the motor and quit worrying about what caused it because you should already know, but you can keep looking and waiste more time if you want. Move on Make sure it's done right the next time, because it wasn't done right the last time otherwise it would not hve burned the piston.

Advise quite d*cking around chasing your tail and pull the motor and fix it, don't let the kids tear your boat up hot roding it all of the time. Fix the carb so that it doesn't run on the lean side and burn up the new engine. Easy no brainer crap, or you could lissen to all of the other crap looking for something that you will never find.

If there is a hole in the piston, something went through it or it melted only choices for what can cause it plan and simple, make it more complicated if you want but you will never catch your tail doing it.

well one of two things happened, it got hot and burned the hole or it jumped the chain and but a valve thru it. What elese do you need to know. Secondly the damn kids where d*cking with it so it's hard telling what else the clowns did, octane boost isn't going to burn the hole by it's self, it would require a lean jetted carb and hot plugs in addition of the octane boost. I'm betting the dumb a$$' drove the piss out of it and floated a valve and punched it throught the piston, then drove it pack to the dock to screw it up more.

does it really mater what put the hole in it? It's there and most likely it's a compination of errors that caused the problem, Rebuild the motor top to bottom and be done with it.

Get a good picture of the number 6 piston and take a shot of the number 6 head area, maybe we can determine if it was heat or possibly something else to blow the hole in the piston, I really dont see any quick cure for this, sorry to say   eric