1996 SPI Top end

[etemplet]

I removed the head and the cylinders measured well within tolerance. Looks to me like a large section of the top ring is missing on the PTO cylinder. Seems strange because there is no damage in the cylinder. Approx a 1 inch section of the top ring is missing.

I want to remove the cylinders but the exhaust manifold will be a bear to remove. Why do they jam the bolts in there in such a way? What is the best way to remove the manifold? Pull the cylinders with the manifold attached? A little insight would be appreciated. I already made a short allen wrench for the job but it won't be easy.

The jet ski ran fine with only a minor issue not related to compression. I removed the head as a result of other minor work.

Thanks in advance !!

 

[mikidymac]

You can remove them with the manifold attached but they will have to go back on with it off then it is used to align them before torquing them down.

 

[etemplet]

How does one remove the bottom bolts on the manifold ? Is there a trick?

 

[etemplet]

What kind of issue would I have leaving the exhaust manifold attached to the cylinders and remove and replace as a unit? I could get away with leaving the cylinders "as is" but I see that broken ring and can't help but want to replace it. It's the mechanic in me.. Ha ha. I mic'd the cylinders and they are well within tolerance. I figure I'll give them a nice hone and replace the rings.

Thoughts ??

 

[mikidymac]

1. It is going to be a pain to install as a single unit.
2. The cylinders could get out of alignment.
3. The torque could be wrong because they are not meant to be assembled as a unit.

Just do it the correct way, it is all detailed in the manual.

A short allan wrench or allan sockets should make it easy.

 

[etemplet]

Ah if it were only that easy.

 

[mwat65]

Are you doing this with the motor in the ski ? Pull the motor use a little heat and save yourself a lot of trouble. That motor is easy to pull.

 

[etemplet]

This is why I am considering pulling the cylinders. Looks like a broken out section of the top ring. The opposite cylinder ring does not look like this. Runs fine but like I said, knowing this issues exists just kinda tugs at me. LOL Exhaust bolts are stuck pretty good and I am not sure heat will be 100% successful in removing them. Very tempted to leave it alone. This ring as been like this for a long time with no ill effects.

 

[etemplet]

Are you doing this with the motor in the ski ? Pull the motor use a little heat and save yourself a lot of trouble. That motor is easy to pull.

Yes I don't feel like puling the engine. I am just what I call tinkering. This all started with me repairing a broken rubber mount for the exhaust.

 

[etemplet]

Pulled the cylinders quite easily and worked the manifold bolts in my vice. What a pain.... constant heating and turning... slow process. I believe the bolts were more stuck in the exhaust manifold than in the threaded cylinder. I am honing the cylinders now. Good thing I continued the process. Does anyone know the OD of stock pistons ? I am assuming around 2.989" I could probably use the old pistons but they are ugly.

 

[mikidymac]

I would just get a set of WSM standard pistons if you are within spec and don't need to actually bore them.

The manual will tell you all the clearance and specs.

 

[etemplet]

I am so good at sniffing out these issues. and one of the reasons I love taking things apart and reading the signs. I dunno if this engine has ever been disassembled. If it has it was a long long time ago.

Anyway, when I got the ski I noticed the oil pump cable was really loose and could not have been working properly. I suspected there may be a problem with the cylinders or pistons but it ran fine after I did the carbs and everything else. I did remove the oil pump right away because I trust them... I prefer to mix my own.

Could this be a cooling water issue ? I am going to look into the amount of flow I need as the ski has an aftermarket Factory Pipe. There is some type of flow adjustment. I'll assume everything is set correctly because the pipe has obviously been on the Ski for a long long time.

I am thinking of installing an additional water temp sensor that I can see. My ski doesn't beep and my fuel gauge does not work so.... I am on my own.

 

[mikidymac]

Nope. That is from being lean. The factory pipes take a bunch more fuel and even factory's jetting wasn't always correct.

Contact [MENTION=51824]Matt Braley[/MENTION].

Also the oil pumps on these are super reliable and will save tons of oil.

 

[etemplet]

Thanks for the input for sure. The coating on top of the piston shows the jetting to be correct. I may check into increasing the jet size and going with different settings on the carbs.

Not challenging the oil pump remaining in place but many old school two stroke guys are gonna have an issue with that. Once you lose and engine because of the oil pump failure there is one sure way to stop that from happening again.

 

[mikidymac]

The tops of the piston are not good. You can see that there is very poor piston wash and I bet if you look at the underside of the pistons you will see a spot of carbon under them so the jetting is not correct and/or the carbs are dirty.

I would agree with you on the oil injection as I am an old school 2 stroke guy too except for the Seadoo's. They are the exception to the entire oil injection ruining an engine. They are the only ones I keep as they are as reliable as can be. In 25 years I have never seen a single one fail. The small 3/32" lines from the pump to the intake can fail after no maintenance for 20 years but the pumps just keep going.

99.9% of the time an engine seizes the first thing people say is that it is the oil injection and to switch to premix when in fact it is dirty carbs and a dirty fuel system causing it to run lean. They typically find this out when they rebuild the engine, switch to premix and it seizes again.

 

[etemplet]

I'll check the pistons more closely. I only put about 5 hours on the ski since purchase and I did clean the carbs and so much maintenance. Whatever is on there was on there before I bought it. I'd like to get the system working correctly. I am going to reassemble at the end of the week when the parts arrive. Suggestions are welcome and appreciated.

 

[etemplet]

The tops of the piston are not good..

If my main jet is 152.5 what would you recommend trying? Also the Factory Pipe fuel recommendations is for 93 octane I would be the previous owner ran 87.

I still wonder how the piston and ring broke and did not damage the cylinder.

 

[mikidymac]

You need to contact [MENTION=51824]Matt Braley[/MENTION] on that one.

 

[etemplet]

Message sent. I've done lots of motorcycle jetting and would probably step up to a 155 from 152.5 but I'd rather get closer to what I need the first try. Also there could be other reasons for the lean condition as you well know. the FActory Pipe Co. paperworks says 93 octane and since most people just run 87 that is probably what this ski has been running. A friend suggested it ditch the factory pipe and go with stock.

 

[Matt Braley]

Can I see a pic of this pipe? They did make one for the 587 but it was very rare and not meant to be fed with a single carb. If someone has put a 717 Factory pipe on there it's just never going to work.

Yes upping the jetting would help and going pre-mix can't hurt. Your friend's suggestion of going with an OEM pipe is a solid one though.

Did you buy the pistons yet? I have new OEM in the box I'd sell reasonably.

 

[etemplet]

Yes I have the pistons and the Pipe on there is made for a the 580SP specifically. I am going to check the jetting and up it a bit. Again, when I got the ski the oil pump cable was not properly adjusted it would not advance the pump at all.

Fuel recommendation is for 93 octane as I mentioned earlier in the thread. I doubt the previous owner ran 93... more like 87.

Also, would I need to run the main a little fatter due to premix instead of the oil pump? I am considering going with 155 main jet, providing I find a 152 in there.