RESTO Another Speedster project

[gfk]

Okay, tried to follow all advice I received: cleaned up the terminal lugs, connected a battery with 13.8V and 200Ah, just to make sure I have plenty of power. Switched the battery switch to "on'', and pressed the starter button for the board-engine once - the rev-counter flickered once, can't tell if the gauges illuminated. Pressed starter button for starboard engine once - again rev-counter flickered once, only now for the starboard engine. No audible beeps. Then switched battery off, waited a few minutes, and turned back on again, and pressed board starter button five times - nothing, pressed starboard button five times -nothing. Disonnected battery, and checked the buzzer -dead, no wonder I didn't hear anything. Couldn't try a keyfob, since I don't have any yet. Reconnected battery, and checked circuits: Interior lights good, nav-lights and anchor light good, bilge pump good, fan circuit is good, but fan is dead, horn circuit good, but horn dead -after all not too bad. When I switch on the lights, the pilot light for the horn comes on, is that normal? The switch for the fuel is push-button, what does it do?
I found a dangling connector (2 core, black and green) behind the dashboard, does anybody know what that one is for?

On to the engine bay: Checked the MPEM visually, all fuses, terminals, overall condition, and it doesn't look to shabby. I found a bunch of connectors with caps and a busbar dangling roughly above the battery, what are they for? Once I have my Candoo, where does that get pugged into?

Connected a positive directly to the starter terminal with an in-line switch, and cranked the starboard engine until no fluid came out through the sparkplug holes - did many bursts about ten seconds, and then let the starter cool down again. Tried to test compression, got 110 at the Magneto side, and only 70 on the PTO side, but only because the starter didn't have enough strength to turn the engine over - the moment I took the tester off, it cranked over again pretty well, tester on, and it got stuck.

Tried the same with the board engine - starter spins, but doesn't engage, looks like the gear is seized and doesn't move forward.

Found massive corrosion holes at all welsch plugs.

So I guess it is clear I have to take the engines out and do a full rebuild on both, so no need to wait for the Candoo. Can anybody recommend a good place where I can order parts, what oversize pistons I can get if I rehone the cylinders (or is it easier to buy new sleeves?), is it okay to shave of a bit off the heads to increase compression, or will that only make the engine fail soon?

I have attached a few photos of the parts that cause me problems

 

[IDoSeaDoo]

Well, I'm not sure I've heard of enough to warrant full rebuilds on both engines. If you know you have rust on your internal bearings, I'd say yes, pull them apart and rebuild. But all you said is that you found corrosion on welsh plugs. That is very typical on these 787's. If you haven't had them welded yet, you will soon. Compression can't be tested with a weak battery or weak cables. You have to be cranking it and the battery still reading 11v. Your other starter might actually work if it gets the umpf it needs from the battery. Try again with a good, charged battery, and never jump it off of a running car or anything, only other batteries. Your carbs look rather crusty, I'd probably go ahead and rebuild those with genuine Mikuni kits. Don't use aftermarket, as these carbs are pretty picky. As for the buzzer, they all die. I replaced mine with a cheap single-tone buzzer from radio shack. Works fine so far, just cut off the connector and splice it in, or order seadoo one, really up to you. The fact that you had both Tachometers swing over was a great win. Sounds like your MPEM is just waiting for a key.
If your lazy starter really is in need of some love, it's better to rebuild the oem ones than to buy a cheap reman. Brush kits and bendixes are all available online. Sometimes, they just need some grease. Make sure the gear in the bendix only spins one way. It's always good to replace them, as they're cheap. Just it might take a super long time to get to you...

 

[gfk]

Fully agree with your comments on carbies and welsh plugs, I will rebuild them with Mikuni kits, no question. The welsh plugs I repair myself, I'll just turn four nice new plug of a billet of 6-er alu and weld them in.
Re. the battery, a 200Ah fully charged to 13.8V and hard wired with 235sqmm Cu cable good for 480A should have enough "uuumph'' to start a 3208 Cat, yet alone a Rotax 787 - it must be the starters being old and tired and corroded. I'll take them apart and measure them through, see if I can't get them going again. Bendix are most likely stuck and full of gunk.
Not knowing the run-hours on the engines yet, what are the lower compression limits and in-balance between cylinders for a re-build?

 

[IDoSeaDoo]

I don't like to see them lower than 140, but sometimes they'll come in at like 130 but come up after it runs a bit. They shouldn't be more than 10% apart. I've heard that 120psi and you need to rebuild the top end. You can always pull the head and check out the cylinders and the top ring. The ring-end gap shouldn't be more than 1mm or something. I forget what it is exactly, but I remember that you can eyeball it and get a good estimate of how the top end is doing. Also, if you have corrosion on the cylinders, it would be a good indicator for why it's cranking slowly or building low compression. The beauty is that you can re-use the head O-ring when you put the head back on. Just be sure to chase the threads, clean the bolts and use blue Loctite on the threads. Also, use that red lealant on the head O-rings when you re-install. The chemicals are all listed in the shop manual which can be downloaded for free online.

 

[racerxxx]

You can't just judge the bore on the ring gap alone, very bad idea. You need to measure the bore. You put grease on the head bolts and blue loctite under the heads, certain manuals had it wrong on the diagrams but spelled out correctly in the directions.

 

[IDoSeaDoo]

so you don't put the blue Loctite on the threads themselves??

 

[gfk]

Bought myseld a DESS-key (unprogrammed, used from a friend) and installed a new buzzer, and tried to check out the MPEM again.
Without key attached, when I press the start buttons, the rev-counters come alive.
When I press either left or right start button five times, I get a short and a long beep.
When I put on the key, I get a single long beep, when I press either start button, I get a long beep.
Can anybody give me a list of fault codes or let me know if these beeps mean the MPEM should be okay?

On the downside, took off the exhaust, and tried to take off the head - one bolt after the other snapped no matter how careful or tricky (very slow with long extension lever, with pre-impacting, with rattle-gun, by tapping it), so it looks like I'm up for a new head, couldn't be bothered cutting the bolts and extracting them.

 

[Ankeneyou]

This is from my manual.

 

[gfk]

Thanks, Ankeneyou, that is super-helpful!

 

[Ankeneyou]

Thanks, Ankeneyou, that is super-helpful!

I can send full quality pics if needed. It looks like the site compresses the pics so they are kind of hard to read once uploaded.

 

[gfk]

No need, the manual is easily legible.
Did you have only one engine-bay fan in your boat, or are there usually two? On mine there is only one on board-side, but I have another opening on starboard side that is not connected to any duct?

 

[Ankeneyou]

Only one the other is an air intake.

 

[IDoSeaDoo]

That really sucks about your head bolts snapping off. I've been there. You can reuse the head, but you might consider new cylinders. It's a tough job to drill those out. If you DO try to drill them out, don't use too thin of a pilot bit. I've had one of those break off inside the bolt, and it's literally impossible to drill out. Has to be ground out. Some used cylinders shouldn't be too expensive. Would be nice if you could find some already paired with pistons.

 

[gfk]

Okay, looks like both my engine are overdue for a full re-build. Can anybody recommend a good shop that does service exchange - I send in my buggered short motor and get back a rebuilt one? Do they usually come with re-honed oversize cylinders and pistons? Can somebody give me an idea how much I have to allow for two engines?

 

[IDoSeaDoo]

Well, there is SBT, who is the largest remanufacturer in the nation. They churn out hundreds of engines per year and are the price competitor. From what I hear, they make the engines run with a little less performance so they last longer. On the forums, you'll find equal amounts of people singing their praises, and calling them crap. Personally, I've had very good customer service from them on non-engine related purchases and know others who have had good luck with their motors. There is also a company called SES (SeadooEngineShop) out of PA. They are a much smaller outfit, but can tailor the build to your specifications. I've spoken with the owner on numerous occasions and he is very well knowledgeable and seems like a solid dude to deal with. I haven't had him build any motors for me yet, but he's probably who I'd go with. Like SBT, he also gives warranties. Both of these rebuilders offer engines in the standard and premium categories. You can expect to spend about $1k per engine. There recently popped up a speculative rebuilder on eBay, offering a built engine with a ridiculous warranty for only $750. SEADOO Sea-Doo 787 800 Rebuilt Engine Core Exchange FREE SHIPPING BOTH WAYS | eBay I don't know anything about them, or know anyone who's used them, but the deal seems a bit too good to be true. Then again, you DO have all those ebay protections to rely on... I'm hoping some people give them a shot and let us know their experiences. You can also do partial rebuilds, like sending your cylinders out to get bored/honed to match new pistons. FullBore is one such outfit. That's if you want to source your own crank and do your own bottom end.

 

[Ankeneyou]

He is in Australia, so any rebuilds from the US would be out of the question due to shipping costs. I'm not sure if there are any exchange type rebuilders over there so you will probably just have to find someone to rebuild yours for you. That probably means this will become a winter project for you.

You could check with Dan at fullboreonline. He sells complete rebuild kits which would be cheaper to ship, and you could find 2 sets of cylinders in the US and have those shipped directly to him to be honed and matched to the piston kit you choose.

 

[Dbone]

Can you tell me where that hose from the top of your oil tank leads to? I bought one that had been cut and I have no idea where it goes also there is another small hose that's just hanging there looks like it might be a vent hose but not sure.

 

[IDoSeaDoo]

It goes to the rear of the motor for the Rotary Valve cavity.

 

[gfk]

Yep, it has a Y-piece splitting it into two lines going to the rotary vale. The second line you mentioned seems to be a breather line, mine stops with a one-way valve above the fuel tank