The Damage...

[dsw222]

I just pulled the head and it looks worse than I hoped. My uneducated guess is that the rings let loose and broke apart, because it looks like they were thrown into the head and cut it up pretty good. Any opinions?

I guess I will start pulling off the cylinders... I just wanted to post some pics first.

What is full bore's policy with heads? I know with SBT, if you do a top end job they dont give you a replacement head... just cyls/pistons

Following are 3 pics of the bad cylinder, 1 pic of the bad dome on the head, and one pic of the "good" cylinder. Why is it discolored around the edges? Is that detonation?

Has anyone gotten away with a top end job on this, or is this a complete rebuild? Ugh, i hope i didnt snap a rod or anything...


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[Dr Honda]

The head is OK. Just use a little sand paper, and remove any sharp edges.

OK... with a shattered top end... I would just do a full engine. The reason is... if any of that got down into the crank... it won't take long for the bearings to give up. So, in my opinion... it's not worth the $$$ gamble to have the bottom end let go. (This is knowing that the crank is the original)

Sorry.

 

[mcfly]

X2. Sand the head down then break down the motor. Not sure about the last pic. Is that the looks of a lean burning cylinder??

 

[dsw222]

Do you have any idea what would cause this, based on the condition of the pistons?

It would be a massive pain to go to premix on a boat with a 40 gallon gas tank as opposed to a 15 gallon ski tank... but I dont want to risk another blown engine

 

[dsw222]

I can't decide if I want to just get it running and sell it... or go with a premium SBT engine and keep/enjoy the boat.

I feel like I won't trust the boat from now on, unless I go to premix (since this is my second engine failure)... but these weren't oil-related, right? Maybe I messed up the carbs when I rebuilt them and that's why this engine went? But it was running great before the rings shattered so that doesn't seem likely either

Blahhhhhh

If i do go with an SBT engine.... the boat would have 2 newly rebuilt jet pumps with fresh Concord props, 4 freshly rebuilt carbs, a new SBT top end on one engine, the other would be a new SBT engine, plus the guy who had it before me had it reupholstered so the interior looks great and has a mint bimini. And i bought a new stereo to install this year.

This was my first jetboat and first time ever doing engine work (or any mechanical work for that matter... I've been buying tools as I go because i didn't own even a screwdriver before getting this boat).

Anyone have suggestions on what they would do if they were in my situation? I don't want to drop 1200 for an SBT engine and then be too scared to take the boat out because I'll think the oil injection is going to fail or the carbs are running too lean or the cooling is messed up

Sorry for venting... i guess just want to hear someone saying "fix it and you will enjoy it and it wont break any time soon"

 

[Phildoo]

Just rebuild it. Premix sucks. Smoke like hell.

 

[Dr Honda]

Dude... you have every right to vent. I fully understand.

Yes... pre-mixing a 40 gal tank will suck... and it will smoke.

The damage is not from lack of oil. The top of the piston gave up, and the piston shattered. It was probably because of the last owner running it hard, and putting it away wet. Rust forms on the rings... and they stick... eventually causing this issue. BUT... those engines are 14 years old. They were bound to give out.

It's up to you on what you want to do. (sorry I can't help with that one)

But... I will shine a little wisdom.

1) If you fix everything... it should be reliable. (all my old junk is proof of that)

OR...

2) Don't fix it... Go ride your skis... and sell me the boat as a fixer-upper.


I'm looking for an islandia, but an 18' boat would work too. (just a thought)

Speaking of that... you going to ride this weekend?

 

[Phildoo]

As much as we all get frustrated by these things, you have to admit, we would miss it if it were gone. I know I would.
So it's either working on the boat in the garage with your favorite station on while drinking a beer or two..
Or inside watching "so you think you can dance" or "the bachelor" with your girl...
Tough call...

 

[95sportster]

The damage is not from lack of oil. The top of the piston gave up, and the piston shattered. It was probably because of the last owner running it hard, and putting it away wet. Rust forms on the rings... and they stick... eventually causing this issue. BUT... those engines are 14 years old. They were bound to give out.

Not to retract from the OP, but I had this exact thing happen to me but my rings were still intact but in terrible condition. A piston shattered and gouged out the cylinder walls and head. Its being sent out for a full rebuild today. Upon breaking it down, I discovered that this was a SBT job since it was stamped on the rods. No idea when it was done. I wanted to find out why it happened.

Dr Honda, how do you prevent rust from forming on the rings?

 

[dsw222]

Speaking of that... you going to ride this weekend?

Thanks for the encouragement guys.

Phil, good point! It sure does beat that.

This weekend I'm headed to a concert at Heinz, and then sunday i'm going home for father's day stuff. So YET ANOTHER dry weekend for me.

But on a good note, I FINALLY got my title for the yami from the Fish and Boat commission.... so this morning I contacted Mike from this board to hopefully get some registration stickers soon. I like his work a lot.

 

[Dr Honda]

Dr Honda, how do you prevent rust from forming on the rings?

Depending on how long it's going to sit....

1) Just start the engine after you are done for the day, and give it a couple good hits of the throttle. That will push out most of the water out of the exhaust... and put a little heat in the engine to help dry it. THEN... when you get home, take the seat off (for a ski), or open the engine compartment to let the moisture out of the bilge.

2) if it's going to be a few weeks before you use it again... when you get home... spry a little fogging oil in to the engine. You don't need the full load like you are winterizing... just enough to help coat things.

Thanks for the encouragement guys.


This weekend I'm headed to a concert at Heinz, and then sunday i'm going home for father's day stuff. So YET ANOTHER dry weekend for me.

But on a good note, I FINALLY got my title for the yami from the Fish and Boat commission.... so this morning I contacted Mike from this board to hopefully get some registration stickers soon. I like his work a lot.

GEZZZZZ! but OK. I was going to go out on Sunday... but I realized that it was father's day... so I'm going to sneak out on Sat.

 

[cheappc]

Wow sorry to hear about what happend..

So since im learning this, I think I got my engine rebuilt after I put a hole in a piston? running lean condition? ummm, so that has nothing to do with oil? Call me crazy but I started premixing after my rebuilt cost me $1,800. But now Im learning it could have been a running lean condition? Wow scary.

Thanks Dr. Honda for the suggestions after taking the boat out, running it a little and open the engine compartment! good idea.

I noticed I have to change spark plugs quite often, but I feel more secure with a little premixing, ummm oh well. I say keep the boat it sounds nice, youll miss it!

 

[6KJR]

My friend tried to short cut when he popped a piston on his sled engine. Bearings SEEMED perfect. Put it together and lasted two more trips before they gave out and had to do a LOT more work. Cant be cheap when it comes to fixing engines itll just cost more in the end.

 

[IDoSeaDoo]

I think it may be partially related to overheating... I was towing another ski with my spx when I blew out a ring. Fortunately, it didn't destroy my cylinder. I think I might be able to get away with just a set of pistons and a good hone (I measured it against the good cylinder with a bore gauge, no diff.) The funny thing is, the PTO piston had no issues what so ever, it was in perfect condition, I mean, it's MINT, ring-end gap like a new piston, no scoring on the sides at all... I have an important question though: I have some pistons that came out of another motor. They measure 81.82mm. I'm thinking of reusing them in that engine, but they need new rings. Where can I get a set of rings that are not like OEM. The cross section of the oem pistons is like an L, where the bottom of the L touches the inner piston. The pistons I have, the rings are flat, just a flat piece of ring all around... I realized that SBT and WSM (and I'm guessing pro-x) all feature the L-style rings... where the hell can I order a replacement set of flat rings? I think they say ART on the inside... seems that's an old Japanese piston manufacturer.

 

[dsw222]

I threw in the towel. The boat is at the local performance watercraft shop. :blush:

They quoted me 1500... and the SBT engine was 1300 including shipping to do it myself... so i said screw it, and hopefully this will get me out on the water faster.

Doc, I'm hoping to be able to take you for a ride within the next few weeks! lol

 

[cheappc]

I threw in the towel. The boat is at the local performance watercraft shop. :blush:

They quoted me 1500... and the SBT engine was 1300 including shipping to do it myself... so i said screw it, and hopefully this will get me out on the water faster.

Doc, I'm hoping to be able to take you for a ride within the next few weeks! lol

Im sorry dsw222, you said $1,500 for the local shop to do it, that includes the engine? thats pretty good..

 

[IDoSeaDoo]

I bet they're just going to put a top-end kit on it. I just hope that they identify the cause of original problem. No way they're going to put a new engine in there for that much, but if they fix the problem and put on new cylinders/pistons, it really doesn't matter if it's a new motor or not.

 

[dsw222]

I just called to check status

They told me a crank bearing on one of the rods (i think thats what he said?) is "right AT the edge of tolerance" so they would either do a top end or a full engine, it was my call... i said do the whole engine. I don't want to mess with this again any time soon.

So new crank and top end, plus i said to order me new RAVE's for both engines (i messed up the shaving of them on the other engine when i rebuilt it), plus evaluation of the oil, cooling, and fuel systems to make sure nothing is going on there (i dont mind paying extra for peace of mind).... its going to put me around 2k with all of that stuff (parts/labor/etc) included. Hopefully not too much more.

The boat is 14 years old, it had the original engines, and as far as i can tell they weren't used much and sat for a while... the carbs were rebuilt last year along with the jet pumps.... so i feel like it was just time for the engines to go.

My only regret is not changing out the crank on the other engine that i rebuilt last year when a piston melted. How long are the cranks expected to last on these?

 

[dsw222]

Ugh....

When i called first, I was quoted at "around 1500 to get it all fixed"

When I took it in, I added on the additional RAVE's and he said "should be 1700 or so" (understandable since RAVEs are about 200 new)

I called to check progress and i got "i'm guessing it will be about 2000"

then i called to give my 1400 credit card deposit so he can order parts and he said "total will be around 2100 to 2300 or so"

Is this going to keep going up???

It will be worth it to get the boat fixed up correctly, but sheesh 2300 isn't exactly close to the original 1500

 

[IDoSeaDoo]

Man, it's not that hard to do it yourself, idk why you're taking it in. I'd just invest in new everything, and put it all together yourself. New SBT engine will run you about $1K, RAVES from SBT (with housings) ~$300 if you buy everything new, including the housings/rubbers/plastics. Hell, you can even buy some new carbs for somewhere around $4-500. How much new stuff are they putting onto the motor?

 

[dsw222]

I priced the new SBT engine at 1200 plus 65 shipping, and figured a hundred or so on assorted tools/gaskets/whatever else. So I was thinking 1400 or so for me to fix it myself.

Thats why when they quoted at 1500, i thought "only 100 bucks to have someone do this for me... sure, ill do that just to save some time". So i took it in. Then all of a sudden its up to 2300... if they said that up front, i wouldn't have taken it to them

Its frustrating, but as long as I get back my boat in good working condition in a reasonable amount of time, I guess its ok

 

[djredman99]

Well, I think you may be right that this will get you back on the water the quickest. There is some value in that.

Also, did they give you good reasons that it went up from $1700 to $2000 and then from $2000 to $2100-$2300? I would agree on a price before they start work on it so you don't get an unexpected "well it ended up being $2700" from them.

 

[IDoSeaDoo]

Just looked on SBT at their premium engines, and the only diff. I can note between the premium and std engine (which is ~900+shipping) is that the premium comes with an extra year's warranty and the gaskets/break-in oil you'd need for the break-in. But both pics of both engines look like they even have new RAVE valves. That's understandable as worn-out RAVE's are a very likely to destroy a motor. And if your problem is indeed just the engine being worn out like the shop said... seems like they're charging you $1K for the labor. I'd call SBT and make sure teh RAVEs are included with the engine (which i'm 99% certain they are). And then I'd call the shop and ask for a break-down of the costs. Maybe order the motor and have them just put it in, but careful, if they screw up the install, it may void the warranty.

 

[Dr Honda]

GEEEZZZZZ.


You should have called me. I would have done the work cheaper. The guys up in Cheswick don't have the best reputation.

Oh well... let me know when it's done so we can go ride. :thumbsup:

 

[djredman99]

So, any updates on the progress of your boat?