help with my 400 dollar project

[hardtarge]

I bought a 1993 Seadoo explorer

The GOOD: hull is good tubes are in pretty good shape hold air

BAD motor is locked up.

2 days soaking with PB Blast NOPE

Pulled the head, Both piston crowns look clean PTO piston is at the bottom Cylinder wall looks clean no rust, MAG Piston is TDC and looks clean as well.
Both are .025 Bored

HEAD? PTO head looks damaged, Pitting near the edges might be a left over from the previous rebuild??

Pump Pulled Nope not pump.

Wacked the Mag Piston with a block of wood and a Dead Blow hammer
ehh nope.

what to look for next.

I'm thinking of pulling the pipe off and MMO down the exhaust so it gets to the bottom end?

 

[Jay_Crims0n]

Sounds like the bottom end might have locked..

Check Craigslist and such for a new engine or rebuild parts.

I have used Craigslist and Ebay and got lots of good parts.

Should not be to hard to rebuild the block.

 

[hardtarge]

thanks been heading down that route. I think i'm going to write the motor off

both jugs look like they have had water/rust creap between the sleve and the head bolt "holes" couple of head bolts pulled out after 2 turns.

not sure if i want to save this motor if it doesn't unlock

local shop is parting out a 720

I think i'm going to pull the as much as they'll let me

bad idea?

 

[hardtarge]

welp i'm giving up on the 580, Dunno if it can be saved or not

here is the head and Cylinders PTO is down head is pitted MAG is TDC

jugs look rusty most of the head bolts only had 2-3 turns on them before they pulled out

majority of the little allen bolts on the head cover rusted away and snapped off

anyways rust alone made me not want to run this motor

found a 720 motor from a 95 XP MAG piston has low compression the shop let me pop the head off pistons/head looks clean, turns over by hand very easy. . Lots of soot no, rust on bolts or anywhere
Motor, Carbs Pipe 200 bucks

 

[ski-d00]

If you're going to swap to a 720, you'll need all the electronics as well, basically the entire electrical system. It will be easier to just rebuild the 580, parts are readily available and cheap. I think SBT has those complete rebuilt motors for like $400 now.

 

[hardtarge]

ok i'm not the seadoo geek here but the only electrical difference between the 720 and the 587 is the stator, Difference 720 uses a clip on top of the motor, and this generation 587 you have to undo the wires in the gray box.

92-94 mpem and 95-97mpem I think the difference was this connector, the combo kill/start switch on the handle bar, and a 30 sec timer to check fuel/hour gages.

I'm hopeing someone will agree with me,

 

[ski-d00]

I have tried swapping lots of electronics over the years and am surprised at how little is interchangeable in the way of the MPEMs. Same motor size usually works ok (except for single vs. dual coil change in the late 90s) but different motor sizes very rarely work, or at least don't work correctly.

when I say entire electrical system, I mean MPEM, stator, pick up coil, etc, the stuff it needs to run right.

timing curves in the MPEMs are different, not just the connectors.

 

[boatmonkey82]

i have only seen one explorer ever and it looked cool as hell ! as for the motor you have just keep your carbs , manifolds , electrical , any thing that is good and throw the rest out the car while running about 90mph , that should take car of it lol . but i would invest in a sbt motor , www.sbtontheweb.com . they guide you thru the whole thing . and i would run a premix instead of the oil pump and be sure to run a premium oil , not your gas station warren oil . sounds like you have a fun project id love to have a old explorer . but i would not waste my time with engine swaps or fixing yours when you can get the right thing ready to run and drop in for so cheap

 

[hardtarge]

I don't think I'll head down the SBT route, $$ the 720 I think just needs a top end kit, it turns over freely, PTO has compression MAG side doesn't, I did pop the head before I had them pull it. MAG side looks very clean piston looked good, walls just a little scrached, very very black and sooty I'll know more when I can put it on the bench and start exploring.

I can get the MPEM from the xp I just don't if the wiring loom will work with it. 95 had the single start/stop. I could find a use for the unused start switch I guess.

I do plan to take the 580 apart as well

 

[hardtarge]

welp motor is out 580 I highly doubt can be saved.

Previous builder snapped one of the bolts holding the jugs on popped both jugs off with out any trouble other then one stubborn bolt that sacrificed itself

Opened up the drain plugs and several cups of brown water flowed out, still locked I guess it can ge a core for someone.

Now that My curiosity was served (or practice dis assembly)

OK group help me out here

580 had clean pistons and pipe, 720 motor very sooty/carbon pistons/pipe. Not sure what this means??

720 NO RUST!!! yea here is a couple of shots of the 720 pistons

Mag has low compression. Poored a little MMO on the mag piston near tdc and it drained away near the ring gap. The gap looks different then the PTO's

What sorta trouble to I have here??

 

[hardtarge]

take a look guys

720 looks blown oh well

found my answer on the soot. Piston wash?

Suggestions on a top end kit?

Any history on the wrist pin bearings?? found the 580 with nice caged bearings. this 720 looks like they are loose like the manual suggests.