Update on old '97 HX Thread....

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Thanks to those who helped me in the old thread from 2017, lol. Been a while since I worked on this thing since I had such a hard time getting the paperwork from the previous owner. It has the 717 engine in it.

Since my last post, here are the latest findings:

1- The wear ring has completely disintegrated, so I am ordering a new one.
2 - Replacing the fuel lines with 1/4" as suggested.
3 - I let the cylinder sit with 2 stroke oil for a few days, then cranked unit over. I am getting 95 psi, using the recommended SeaDoo manual and youtube videos on compression testing. With a new battery, it cranks over fine. When I put both plugs in the starter clicks and struggles to turn the engine over; even if bypassing the solenoid so I figure the impeller is stuck (possibly plastic pieces lodged in jet drive or the starter needs to be replaced. Thoughts?
4- Worse case, I will end up replacing the rings and hone the cylinders if still in spec
5- Didn't replace the oil tank, added extra tubing with new oil to recirculate and will make sure the new owner is aware of the option.
6- completely washed and degreased inside compartments

I don't have a lot of info on why it was stopped being used, so not even sure if it was just put in storage or if it was having issues. I haven't started it via gas since the cranking issue is happening. It should start even with the low compression (apparently 120 -150 psi is the norm with good rings); just don't want to cause any damage inadvertently in case it's a jet drive or impeller issue.

I now have a 2001 Yamaha that I am rebuilding (injection lines came off of carbs; common issue apparently), so once I have this HX squared away it will be sold. What are these things going for in clean shape, which this one is since it's been in storage since 2008? Online, the prices are all over the place.

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If it will not crank with the plugs in it is typically a bad battery, yes even new batteries can be bad and I have seen a few Walmart EverStarts do this.

For there check all cables and connections and finally the starter could need new brushes.
If it will not crank with the plugs in it is typically a bad battery, yes even new batteries can be bad and I have seen a few Walmart EverStarts do this.

For there check all cables and connections and finally the starter could need new brushes.

Yes Indeed. I.... even put a 1000cca battery and connected it to the NEW Battery VIA jumper cables on the my wife's ski that I had just built. It would not turn over. I fought that ski and checked everything 5 times. LOL I put an old battery in there for some reason and the dang thing turned over like a champ. Trust nothing. :D
Worse case, I will end up replacing the rings and hone the cylinders if still in spec

You can try that, but likely a top end job needs to be done if compression readings are accurate. New rings and honing is not likely going to improve compression. Does it turn over easily by hand with the plugs out? Not just the cylinders being rough, but the crank may be rusty if it sat for an extended time.
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Yes, they turn over fairly fast tbh (with plugs out). I tried 3 batteries yesterday (2 from working lawn mowers that are 325 CCA and from my Ram 2500 batteries with) same results. I am thinking the starter is the culprit. I checked the manual, it says to check the impeller, which it doesnt seem to be fbinding, so for $40 its kind of a no brainer. Brush kit is half that price, but labor (my time) is tight so Ebay, here I come.

I have rebuilt outboard engines that sat for a long time, just replacing the rings because they end up staying collapsed or stuck to the piston channels. Just did this on a 10 hp Mercury that had sat for 13 years. The compression test on it was 25 psi on both cylinders. Tore it apart, replaced with stock size rings after simple hone, and bam, 120 psi on each cylinder and runs like a champ.

Figured I should be able to do the same on this 717. BTW, thanks everyone and kudos to Rotax for making it simple to tear into the heads without much trouble! I used to race Aprilias and the Rotax engines are prob my fav manufacturer. I'll post up pics if I get the time.
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If the compression numbers are ok there is no reason to do rings on these.
And on the flip side if they are low you need an overbore and new pistons and rings. Just doing rings on these really doesn't do anything.
Once I replace the starter,I will see if I can at least get it to fire up. I will pull the heads and check them both visually and with a micrometer after that; I don't like to sell things that are a potential issue for the next person. I have a guy here locally who does all my head machining, so he'll check them out as well. I really like that I can pull this thing apart without much trouble, where the Yamaha 800XL required me to pull everything apart just to get to the heads.
I understand not wanting to pass on a problem but if the compression is good and it starts there is no reason to pull the head.

If you pull the head you risk breaking head bolts and will need all new o-rings. Even if you have a bore gauge measuring the bore isn't going to tell you if the pistons or rings are worn.
Of course, I don't want to go down that road, for time or money reasons if I don't have to.

The problem I have though is I am getting 95 psi from each cylinder. From videos I am watching for 717 engines, that's about 25 to 30 psi, per cylinder, low. I read each page in the manual, and unless I am blind (which is possible, lol), I can't locate an actual statement about average or optimal cylinder compression numbers.

I guess it boils down to either I rebuild the total top end, which will take more money and time and have satisfaction it's done right, but less money out of my pocket overall, or I sell it being honest with the person about the 95 psi and then take a hit on what I can ask for the unit.
150 psi is perfect ad at 120 it is done and needs to be rebuilt.

Since it's been sitting for so long I would see if it will fire ant then recheck compression.

Also verify your gauge is accurate, the Harbor Freight ones are not.
mikidymac - Will do, thanks for the help! Looks like a full top end kit is around $250. I may just go ahead and do it anyway, time permitting. At least this way I have peace of mind and can ask more for it. Some pretty good vids on youtube also, I didn't realize the 717 was a pretty popular engine.
You need to have the cylinders bored to fit oversized pistons, you can't just slap in new pistons and rings and expect the compression to come back up as the cylinder wears out too.
Thanks ya'll! Ordering a new batt, wear ring for now. The more I read on the forum, I need a better compression tester and test WOT. I am in fact using a HB tester also. I have new fuel lines and left over Mikuni carb rebuild kits from another engine that uses the same units, so I will redo this thing right and then list it. Appreciate everyone's input! I'll update as I go along with this thing.

BTW, I HATE THIS ETHANOL CRAP! EPA has already owned up to it being crap, lessen mileage and destroys fuel systems. Can someone please tell me why they are still forcing this crap upon us?
Update: Decided to pull the carbs after I rebuilt the starter. These things are very clean, so the person who "stored" it did a good job. What concerns me though, is they didn't put back the small strainer filters back in either carb when it was serviced. I have Mikuni rebuild kits, so they are going in, but still.... They def installed a block off kit for the oil injector. I refer that anyways in all my 2 strokes.

I got a bit concerned, not used to this Rotax. I was feeling inside the intake manifold and only felt one "reed", so my first thought (like most 2 strokes and reeds, was, "did this thing eat a reed", because my finger went all the way into one of piston ports. Duh, rotary valve, lol.

**** Yes, the corn lobby. Hopefully, one-day things change and this crud is done away with. Even emission wise, it's horrible, and that's using their own data.


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