1990 SP Hard to start after sitting

[Jake907]

Hello, I have a 90' XP that I just recently revived from a pig farm. The ski works great... when I get it started haha. My issue is that if it has been sitting for some time or if it's running and I shut it off for >5min it has difficulty starting. It will eventually start but it takes me pressing the start button probably 6-10 times for 2-4 seconds at a time for it to actually get going. Right before I actually get it started, after it's been sitting, it sounds like it has a weak sputter almost like it's having to re-prime everything with fuel. The odd thing about this is that when I'm riding it and shut it off, fall off, etc. for a short period of time and try to restart it, it fires right up without any sort of difficulty. Any help would be wonderful!

Things I've done to this ski:
-New battery
-All new fuel & oil lines
-New fuel filter
-Tore apart and cleaned carburetor and oil pump assembly
-Rattle can paint job

Also I stripped this ski all the way down to just the hull and cleaned everything from oil and fuel tank to the jet pump

 

[Spider4real]

I had a similar problem. For me it was a bad seal on the fuel filter. The o-ring was bad and letting air in.

Also could be the carbs. Did you just clean or did you rebuild with original mukuni parts.

Maybe weak compression? Have you checked?

And FYI, the XP was first introduced in 1991. Do you have a yellow or white engine?

 

[Jake907]

Thanks for the info!

It's a yellow engine 587 single carb. Year is a 1990 and model is a 5803. Must be a SP. I don't know why I kept thinking it's a XP.

I replaced the original fuel filter with a aftermarket inline one that's sealed so I think I'm alright there but I'll double check. Did having air leaking in cause it to run roughly or anything?

I tore the carb completely apart and cleaned out all the jets. I didn't rebuild it though. I may be wrong here but I believe it was the main jet that has a (10 or 13mm??) Nut holding it in that is next to impossible to get out due to the sockets I had being to think. I most definitely got it cleaned out though haha.

I was talking with some friends and I'm also kinda leaning towards the side of weak compression. It makes sense that it starts fine when it's warm because the piston rings have expanded due to heat thus making for better compression and when they cool they shrink allowing enough blow by for bad compression hense the difficulty starting. I bought a compression tester and it should be here this weekend so I'll take a look at it then and update.

 

[Spider4real]

Unfortunately the yellow engine has a different type of carb than all the other Seadoo's so I will not be much help there.

Surprisingly mine was running good once it started but the air leak was probably running the engine lean, so had I not found the issue i would have likely killed the engine.

I have no experience with in line fuel filters, but the general consensus around here is they cause more problems than good as they restrict fuel more than the oem filter. I would put the original filter back and see how it works. That might be your issue.

And when you have the results from your compression test let us know. Cheers

 

[Jake907]

No worries and unfortunately the oem filter was severely dry rotted and broke into many pieces when I tried to unscrew it. I'll look into getting either an oem one if I can find it for a better aftermarket one.

I've definitely had issues with it running lean.. mostly I think it was my error in improper adjustment of the fuel mixture screw. I have noticed that when out of the water it likes to overspeed/runaway which is fun to deal with (rag shoved over the air intake stops it no problem) but when it's in the water it never has an issue. I have adjusted the fuel mixture screw to run fairly rich (mostly since it's a 33yr old engine and a little extra oil is ok) and haven't had to much of a problem since. It definitely does idle a bit higher out of the water.

It may be a combination of both compression and air leak at the filter. Will keep posted about it.

 

[Jake907]

Alright I got my compression tester in today. Rear cylinder read around 123-125 and forward cylinder was 133-135. The plugs on this thing also geat really dirt really quick which I'm not sure is normal or not for these engines.

 

[Spider4real]

The rear (PTO) cylinder seems to be near the end of its life. From my understanding when it hits 120 you definitely need a rebuild. So the 125 I assume might be causing starting issues.

But I think I might try to find an OEM fuel filter water seperator first to see if that helps.

I am not much of a plug expert, but can you post pics and hopefully someone with more experience than me can chime in on their condition.

 

[Jake907]

I agree with you on the compression. I was digging around online and from what I could find it looks like factory compression for the 587 yellow is around 150 so mine is definitely low (is also a 33yr old engine so... haha)

As far as the fuel filter goes, should it be full all the time or not? I pulled off some of my intake so I could look at it and it's sitting at just under half full of fuel. I started the jetski up and let it run for a bit and even after that it was still only sitting around half full. Also instead of getting a oem filter would one like the link below work? It's of similar design and I'm just kind of skeptical about buying a used one off ebay since I can't find anywhere that sells them new.

Amazon.com : 61n-24560-00-00

Also I've attached some photos of the fuel filter, plugs, and the ski itself.

 

[Spider4real]

Yeah, 150 is the norm for the 587, 717 and 787 engines.

In all honesty I would not be too concerned about a used filter assemble from eBay. My ski is a 92 XP and the plastic is still in great condition. But if it makes you feel better you can buy a used one from a ski that is 10 years newer than yours. Just buy a new filter/strainer to go with it. And those filters in your link seem ok to me, but I am not an engineer. I personally would prefer a used OEM vs something I am unfamiliar with.

Your current filter will require much more effort to pull gas through the filter. But I am not really sure if that will be enough to cause your hard starting. I think the easy way to find out would be to bypass the filter and see what happens. If it starts right up, then look for a OEM filter. If no change then maybe stick with what you have.

But I would have thought the filter would be full. Not really sure why it's almost empty. If you are going to keep this filter I think you need to bleed the system to get the air out. Maybe someone with experience can offer some insight into this.

Also, your plugs looks like they are pretty oily. So seems rich to me. Which for me it better than to lean. But might also cause starting issues if they are too wet.

By the way, do you pull the choke when you are starting it cold?

The ski does look good for its age.

 

[Jake907]

Update to the filter. I tried to bleed it earlier today since I had everything off. I put in one of those squeegee bulbs that you would normally fine on any outboard motor so priming it is cake. I disconnected the end from the mechanical fuel pump and when I started squeezing the bulb gas came out right away with no air. I squeezed it quite a few times and it was always straight gas without air. The amount of fuel in the filter never changed either so this filter may just be designed like that. I'm going to look into getting a oem one.

As far as the plugs go, I'm definitely running it a bit rich. Since it's such an old motor without anything done to it, figured it'd be better to have a bit extra oil going through it. Also I found it runs and idles alot better being slightly rich.

I do not pull the choke pretty much ever. Found that when I do it kills the motor and it will never start whether it's been running or im just starting it for the first time.

Tried to take it out on the lake earlier and after launching it, the starter wouldn't go. Took it back and checked the solenoid which worked fine and then pulled the starter (engineers really did a good one with designing that SOB). Starter will run fine maybe once every 10 trys and for the most part it is incredibly weak. I hooked it to my car battery to make sure it wasn't the ski's battery too. Need to get a new starter for it.

I'll be busy for the next couple weeks but after that I'm going to get the starter/top end kit/filter for it.

Here's some pictures of what it looked liked after I pressure washed all the mud off it before it got painted.

 

[mikidymac]

Get rid of that aftermarket fuel filter.

Yes, compression is low and that engine is on it's last leg.

 

[Jake907]

Update to the jetski:

Took the cylinders and pistons out (only took about a half hour). Looks as if the forward piston had something done to it at some point (it had aftermarket wrist pin bearings on it) and the aft one was completely factory. Took them over to a local machine shop and they are right at 76mm bore diameter. There is some scuffing on the cylinder walls and you can tell that it was ran very lean and hot at one point in its life. Looking at getting the cylinders bored to 0.5mm over standard and am rebuilding the top end. Also found new oem fuel filters on ebay for $25 so I'll be getting one if those. Will be out of town for a few weeks so I'll work on it when I'm back.

The lower end looks great from what I can see looking down through it. I was looking through the manual but couldn't find anything on replacing the crankcase oil. Anyone have any info on that? I know there's a drain plug on the bottom of it I believe under the carburetor but other than that I didn't see a thing about replacing it.

 

[Spider4real]

There is no oil to replace. Only the rotary valve is filled with oil and there is no need to change that unless you are switching brands then you might want to disconnect the lower hose to let as much out as you can (which will also let the oil out of the oil tank and make a mess unless you clamp the hose). There is no drain plug for the rotary valve. There should be no oil in the crankcase. If you have oil in there then the crankcase seal for the rotary valve is leaking and you should probably replace the seals since you are this far into it.

The drain plugs you are referring to are for draining a flooded engine in case you flip or sink your ski. I have never had the pleasure of using them yet.

 

[Jake907]

Ahh makes sense! I read the part about draining the engine of a flooded ski which I'm going to have to do for a different jetski that's been sitting full of oil/water for 4yrs.

It must be the rotary valve seal like you said that's leaking. There's a tiny bit of oil in the very bottom of the crankcase, maybe like 1/16th - 1/8th of an inch. I'll drain it when I get back and see exactly how much. Would running it with a tiny leak in that seal hurt anything? I'll probably eventually replace it but I'd rather pull the motor to do so since getting in that area is not very fun with the engine in the ski. I'd like to fix the top end and use it through the rest of the summer and then work on it more in the winter if I can.

 

[Spider4real]

Based the amount of oil you think is in the bottom of the crankcase I do not think it will be an issue. You will just get a nice puff of smoke when you start it. If the leak gets worse you could always put a valve on the oil line to prevent too much from getting into the engine. But as of now, I would do as you suggested and ride it for the season and fix it over winter.

 

[pagery]

First bit of information i've found online regarding similar model as my own Jet ski which I just started repairing this weekend. Wish I could be helpful however I a novice when it comes to this stuff. I bought my 1989 SP when I was 16 and have had many repairs. Trying to get it operational before the 4th!

Just wanted to chime in and say thank you for the knowledge I've gotten from just this thread, far above and beyound what I've found on reddit which typically doesn't relate to my make or model and youtube. I set myself as a watcher to see how the progress goes!

 

[Jake907]

Alright so after having had the wrong size piston shipped to me and dealing with that I finally finished everything up. I went with the 0.5mm oversized piston which I found on Amazon for right around $200. I also swapped the fuel filter to the stock one I got of ebay and threw in a new starter which was surprisingly cheap off Amazon since the old one decided it didn't want to spin anymore. I got bored while waiting for things and installed a drain plug too because for some reason this model did not come with one of those.

Took the cylinders out to a local machine shop who bored them out and then diamond honed both cylinders and even blasted them to remove all paint and dirt for $245 which seemed pretty reasonable. Everything went back together pretty smoothly besides fighting to get the rings into the cylinder with just my hands which was lots of fun but I eventually got it. I checked the compression and fwd is pulling around 147# and aft is pulling right around 145#. Once I got the fuel lines primed it fired right up! Turned it off and let it sit for awhile then I went back and I barely had to press the button to get it to fire up!

Overall it took me maybe an hour to pull everything apart and right around 2 hours to get everything back together. It's a pretty straight forward process and now I have a 33 year old ski that will live on!

 

[Jake907]

Well I thought everything was fixed but after breaking it in today I found some problems.

Rode the ski around for maybe a half hour in total and seemed to have compression issues again. Took it back home and compression checked it. Readings for both the cylinders were 130 which is much lower than when I compression checked it before running it. Popped the head off and looked at the cylinders which look great now. I did notice that the ring end gap is definitely wider at the bottom of the stroke than at the top by at least double the width. Unfortunately the feeler gauge I have is to large to get in that narrow of a gap. Does anybody know what might cause this?

Also the cylinders seemed to have a bit of fuel/oil left over in them. Is that normal too?

 

[Spider4real]

I wish I could offer some helpful feedback. It almost sounds like the bore job was not done correctly as I doubt you could have worn the cylinders in 30 minutes to account for the ring gap increasing as the piston goes down. There should be no taper on a new cylinder. At least that is my understanding.

I do know it takes a bit of time to rings to set when new and compression typically will be better after a full break in.

DId you add some oil to the first tank of fuel to help the break in process?

Hopefully someone with more experience can chime in to this one.

 

[mikidymac]

The cylinders should have no taper.
Compression should be going up as the rings seat, not down.

Oil and fuel is common in the cylinders as this is a 2-stroke.