very poor compression... need to rebuild '94 xp 657x

[seabass]

Back already

it was running great while it lasted...

had it out most of the day for the last two days... then I did a little show boating.. had the nose straight up in the air .... then she died

there were no strange sounds or anything... bought it back to the house and did a compression check... one cyclinder 75psi the other under 25psi uke:

so it looks like i need to get a rebuild kit...

can anybody recommend if I should go with the platinum kit... I see there is a guy on the net (full bore) where you send in to have them bore... is boring needed or can I put sleeves in it to make the job easier? I'm starting to do some research on the net now to figure out what tools are needed..

Bills86e r u out there?

thanks for the help in advance

:bigear:


**edit** one more tid bit of information... I did notice one of the spark plug gaps was closed up a little bit... possibly from the piston?

 

[Bills86e]

IMO, you should pull jetpump, then pull the engine out. Then decide get another
engine, rebuild this one, or go the re-manufactured route. Other choice is to part it
and use the money toward another ski (maybe faster one).
Your damage described, suggests bits in lower cases, crank damage, so its either
a complete rebuild, or break it down to a short-block & use as a core trade in.
You have not described your mechanical skills, but a re-build (like breaking bolts ect) takes alot of talent. Either of these two choices, you would still have to update
ALL of your other integral engine parts and fix/replace and update so the new engine performs. Let us know if need more info on what I just described. I would be typing all nite just to mention tools you'd need to buy or rent!! Bills86e

 

[seabass]

Thanks for the reply Bill

Maybe the spark plug was gapped liked that, and it didnt hit the piston... its just looks closer than .021.

I mean.. the ski will barely start up .. but it wont stay running very well at all.

So, do you think I would be wasting my time sending it in to full bore and just redo the upper case? Do you think there is a good chance of crank damage?

I plan on taking the heads off tomorrow to look at the extent.

Thanks

 

[voodoo]

You never know how many worms are in the can until you dig in below the first layer, if piston pieces are missing they are interwoven with the crank bearings - remove everything and flush with kerosene and proceed to diagnose the damages carefully or read the fullbore shipping info/sbt is about the same idea but you have to figure out the timing with sbt exchange method.

 

[seabass]

thanks for the reply

well this is what we have here... :ack:

pieces of the piston are broken off the one cylinder. you can see a piece of the ring embedded into the head :hurray:

I would really like to just get some piston heads and rings and make it through the rest of the season... is this doable or a was of time? the cylinder walls looks surprisingly fine.

I have the shop manual and might have to rip this puppy apart before the weather gets really nice...


thoughts please...


thanks for all the help :cheers:

 

[Bills86e]

schard in case

What happens in the lower case is a BIT can just Tear UP the crank seal, a bunch
down there would be instantaneous - disasterous IMO. Others may say "just rinse them out". I advise split the cases. JMO


Am I seeing ten broken headbolts in there?

 

[seabass]

Bill...

it must be the weird angle of the shot...

sitting here contemplating what I should do..

Itd be nice to have the job done right...

Will I be able to tell if the bearings are good when I pull the crank?

Thanks