'95 Seadoo sp - Engine Turns Slowly

[fickesd]

I just purchased a '95 Seadoo sp and diving into it to get it running. When I connect to boat battery (not jetski battery) via jumper cables and hit the start button (with Lanyard on), the shaft turns very slowly. If I repeat but instead of hitting the start button, I short a screwdriver across the starter solenoid, it turns faster but still seems to slow to start, in my opinion. I wondering why the difference and what I should be looking to do next. I haven't taken the starter off yet to test on the bench only because how difficult it seems to get to the bottom bolt. On a side note, I am able to turn the shaft by hand pretty easily and it does feel like it has compression.

Here's a video of when I shorted the solenoid and the shaft turned faster than when I used the start button.

Additional information. When I do a continuity check across the solenoid when I hit the start button, I get 2.2ohms and only about 8.5 volts. I assume I should have gotten the 0 ohms and the full 12 volts. Does that sound like I have a bad solenoid?

 

[artr]

The solenoid contacts are probably dirty/corroded causing the difference in starter response. The solenoid should be replaced. It actually does not sound that bad in your video and would probably start if other conditions were right (spark, fuel, air, compression). If the starter is original then you may need to eventually replace the brushes, clean the commutator and lube the gears and bendix. You could check compression now by using the screw driver to turn the engine over.
Does it still have the gray fuel lines? If so then replace them with standard automotive lines and rebuild the carb using a genuine mikuni kit and follow the carb rebuild thread at the start of this forum before running it more than a few seconds. Check the oil lines are full and not deteriorated and the oil pump is set correctly. Probably should change the oil filter and clean the fuel filter/water separator. Unless you know these things were done you may need to do them to be certain things are set up right.

 

[fickesd]

Thanks for your reply. I replaced the solenoid today but it exhibits the same issue. Meaning that it barely turns over the engine when I use the start button and turns over the same as the previous video when I short it with a screwdriver. I checked the compression and I had about 95 in the front cylinder and about 105 in the rear cylinder. I'm guessing that is low but I was thinking that is should still fire above 90psi. ). I checked for spark and both had spark when use a spark tester, but I really couldn't see one when I just tried grounding the spark plug. I put mixture of gas/oil down each cylinder and some in the carb hoping I could get it to fire but it never did. Just as a side note, everything looked really clean in the electrical box, almost like the previous owner was replacing components. I would like to figure out why the start button isn't working properly so I don't have to keep shorting the solenoid with the starter but I don't really want to go to far if I can't get it to fire with starting fluid down the cylinders. So here is what I think my next steps are going to be but I'm definitely open to suggestions. 1) Replace spark plugs and try to see a spark (without the spark tester). 2) test the start switch, but not sure how. I was thinking I could pull plug from solenoid and look for 12v when I hit the button. Any suggestions would be appreciated. It's my goal to get the jetski running before I go back to work after the holidays.

Update: definitely no spark

 

[tobytd]

It needs rebuilt. With compression numbers that low it probably will not start in the water, even if you do get it running.

 

[artr]

There are some things I would do first that are not too complex.
1. Is the compression gauge you used a known good one? If those readings are accurate then it won't start in the water and may not start even out of the water. Maybe someone with more experience can chime in on that.
2. Is the battery you are using to test things full charged and load tested? Does it start the boat no problem? You are not running the boat when you jumper the battery to the jetski cause you could blow the MPEM. Use a voltmeter to measure directly across the battery terminals while the jetski cranks. It should hold close to 12V if it is good. If it drops down (like to 8.5V that you mentioned above) then that could be the reason for no spark.
3. You can test the solenoids standalone. Disconnect the battery and starter cables from the top of the solenoid and put an ohmmeter across those 2 terminals. Disconnect the black and yellow-red stripe wire from the base of the solenoid and jumper 12V to where the yellow-red wire connected and Ground to where the black wire connected. You should get 0 ohms across the top 2 terminals. I have read where new solenoids are sometimes defective.
4. You can test the start switch by finding the black and yellow-red stripe wires that run from it to the MPEM (different than the same color wires that go to the base of the solenoid. Disconnect those wires (there is a connector in-between the switch and MPEM) and measure the switch with an ohmmeter. It should be a normally open switch and measure 0 ohms when pressed.
5. I'm not sure that you should pour premix directly into the cylinder, only into the carb. You may be flooding the engine and preventing it from firing
6. If you used an inline spark tester that showed activity then the new plugs could help.

 

[fickesd]

Thanks again for the reply...

1) I believe the compression gauge is good. The compression seems to be getting better the more I try to start it. I am now at 110/120. I'm thinking about trying the sea foam deep creep and checking it again tomorrow. What compression would be considered acceptable? 120 or higher?
2) Battery starts around 12.5v and holds to 11.47 volts when cranking
3) Solenoid tested good
4) I tested the start switch and am seeing about 2.2 ohms across the terminals when I press the button. I'm going to assume I need that replaced but waiting until I figure out the ignition/compression problem first
5) thanks for the advice
6) measured the ohms across the two plug wires and got 21ohms. Not sure what I should get but another youtube showed it should theirs should be between 9-15k but I'm not sure I have the same model.

Would also like to ohm out the MPEM to see if it tests good but I'm having trouble finding the table with the values for my model.

Thanks again for your help. I'm new at wave runners so every step of the way I'm learning something.

 

[artr]

You can download the shop manual for your model at seadoomanuals.net. In it you should find the table of resistance values for the MPEM, probably the tests for plug wires and other useful info and tests.
You can short the connections at the connector where the start/stop button connects and see if it cranks better. If it cranks the same then no need for a new button.
Ideal compression would be 150. I've read when it gets below 135 you can start to see problems like hard starting in the water. You should hold the throttle open when cranking during compression testing. That may improve the compression numbers by injecting some oil. I would not use the seaform as it would strip the oil film that protects the cylinder walls.

 

[fickesd]

Today I took the head cover and the head cylinder off to get a look at the cylinders & pistons. From what I could tell the pistons looked pretty good, but the half that had the lower compression (110psi) had very small vertical scratches across approx. 75% of the cylinder wall. (see picture). The other cylinder looked and felt pretty good so I'm not sure why it was only measuring slightly higher than 120psi. Based on the description and the pictures, would you recommend that I need to do a complete top end on both cylinders? And is it more economical to take the cylinders to a machine shop and then try to find the pistons and gaskets to match or just by the entire kit for $400. Also, I'm wondering what caused the scratches. Do I have to worry about replacing the top end and what ever caused the scratches end up scratching the new walls? Where's the best place to buy the new top end and where's the best place to find instructions?

 

[burtshaver2021]

Today I took the head cover and the head cylinder off to get a look at the cylinders & pistons. From what I could tell the pistons looked pretty good, but the half that had the lower compression (110psi) had very small vertical scratches across approx. 75% of the cylinder wall. (see picture). The other cylinder looked and felt pretty good so I'm not sure why it was only measuring slightly higher than 120psi. Based on the description and the pictures, would you recommend that I need to do a complete top end on both cylinders? And is it more economical to take the cylinders to a machine shop and then try to find the pistons and gaskets to match or just by the entire kit for $400. Also, I'm wondering what caused the scratches. Do I have to worry about replacing the top end and what ever caused the scratches end up scratching the new walls? Where's the best place to buy the new top end and where's the best place to find instructions? View attachment 64663View attachment 64664View attachment 64665View attachment 64662

Your going to need to take the cylinders to a machine shop, they will tell you what size pistons you need and bore the cylinders. Make sure they chamfer they ports. You will need to figure out why you had damage to the one cylinder, go through the carbs, fuel system and verify the oil injection is working as it should. I’m going to guess, go out on a limb and say the cylinder with 110 pounds was running a little dry and not getting enough lubrication, you will need to run pre mix as well as the oil injection for your first tank of fuel after rebuild. I would go with WSM for piston kit from OSD marine.

 

[mikidymac]

Those pistons are dry, there is no piston wash so you need to be looking at the fuel system for sure.

And yes, cylinders are badly scored.

If it was mine I would send the cylinders to Group K for boring and new pistons and rebuild the fuel system and check the oil system.

 

[fickesd]

I got a little deeper into the engine and the electrical system today so I had a few more questions. I went to remove the cylinder and notice a bunch of Sand along side where the bolts are (on one half). Is that normal or could that be the cause of the scratched up cylinder walls. They were in both cylinder housing and only the one cylinder wall was scratched up. The sand wasn't where the pistons went up and down or not at the point of me taking it apart. see pictures. What is the path where the sand can get in? Second, I got the 4 bolts off to remove the cylinder but how do you pull the cylinder out. The piston gets stuck when I almost have the cylinder all the way off. I am just afraid to pull too hard without asking you guys. I did find on Ebay where I can buy the cylinder, pistons, gaskets, etc... for about $400+. Is it better to just do that vs find a local machine shop and then buy the larger piston, gaskets, etc... for about $266. It just seems like the machine shop would charge more than $150 or atleast close to that amount.

Regarding the electrical. I tried to ohm out the MPEM per the repair manual but many of the readings were O.L for the ones that had to be > than something. Is that right or should there have been a reading? See the picture. Also one of them that needed to be > 10kohm was actually 9.8Kohm, I assumed that was close enough. I also couldn't do one of the checks because my MPEM didn't have that wire color. Not sure if I need a new MPEM or not based on the readings but I'm still not getting spark. I did check the coil resistance and that seemed to check out per the Ohm reading. If you think the MPEM is still good based on the readings in the picture, what should be the next thing I check. I can't turn it over now since I have the engine partially apart but wasn't sure if there was something else I can verify with the ohm meter.

This has been a learning experience, even though when I bought this on facebook marketplace the person said there was absolutely nothing wrong with it. Apparently he meant nothing other than no spark and low compression and a bad start switch (that I know of so far). He was also not honest about the trailer. He said all it needed was a tire. Turns out I am having to replace everything but the leaf springs. Good thing I only paid $200 for everything so I did expect it not be perfect but if I had known I was going to potentially put this much money into it, I would have bought a 3 seater. I know I should just sell the fixed up trailer and dump the jetski but I am learning something and would feel good if I could fix it.

Thanks again for all the help, it's really giving me the confidence to keep going.

 

[burtshaver2021]

Really not trying to be a jerk but did you really expect to buy a Seadoo and trailer for 200.00 and have it be perfect. Lucky to get a project ski
Without a trailer for that price. Should at a minumum do a compression test before purchasing a running ski. The sand you see is in the water jackets and is completely seperate from the cylinder bores and did not cause the scratches. Obviously clean the sand out of there while it’s open being very careful not to get any in the bores and once running back flush it periodically

 

[fickesd]

I'm kinda at the decision point that is why I'm trying to also figure out the spark issue. I haven't made any investment in the jet ski yet and what I have invested in the trailer I could likely make it back if I just turned around and sold it. But I'm getting the desire to see if I can fix the ski and learn something in the process. Thanks for validating that the sand is ok. I was thinking that was part of the cooling system but it was good that you were able to confirm that. Now I just need to figure out if the MPEM is ok and order up the cylinder/piston kit.

 

[burtshaver2021]

I'm kinda at the decision point that is why I'm trying to also figure out the spark issue. I haven't made any investment in the jet ski yet and what I have invested in the trailer I could likely make it back if I just turned around and sold it. But I'm getting the desire to see if I can fix the ski and learn something in the process. Thanks for validating that the sand is ok. I was thinking that was part of the cooling system but it was good that you were able to confirm that. Now I just need to figure out if the MPEM is ok and order up the cylinder/piston kit.

Makes good sense, you got a real good deal on this ski and trailer at 200.00. Either way you go, whether you sell or continue you can’t lose at this point getting in at 200.00. You could sell the machine now without investing a dime and probably get the entire 200.00 for it, have the trailer for free and look for a different machine but it’s just my opinion but don’t expect to find a water ready machine at that price point, make sure you water test if your buying one that is water ready, On the other hand you could keep this one Especially if you are enjoying working and learning on it. I think your on the right track in regards to getting spark first before making a decision, I always feel like I’m golden once spark has been confirmed and the crank seems smooth as the rest i feel is fixable. My only piece of un asked for advice would be if you do attempt to repair this ski, take your time, take the time to learn and understand, cover all your bases and it will serve you well, learn how to and do a leak down test, do one before and after your rebuild, rebuild the carbs using a back to OEM kit from OSD marine and follow Mikidymac’s carb rebuild thread, again don’t skip any steps, test your pop off once your done, and pressure test it. Verify the needle and seat are not leaking. Tje top end is going to need to be bored, I’ve heard of replacements from SBT where you will get cylinders that have been bored 1mm over with pistons, rings or you can have it done yourself if you can find someone that knows what they are doing do your machining, make sure all work is within specs, you can easily check your ring end gap, my point is, throwing a set of rings in, isn’t going to work. You see so often, where a top end rebuild was done and after it’s not working properly or it loses compression again very quickly and when you ask, no carb rebuild was done, no boring was done, they don’t know the measurements of the note when the pistons and cylinders where installed, no leak down test was done, pop off wasn’t checked, and they are wondering why the top end rebuild has went south. Anyways this post was meant to help, I know you didn’t ask for my opinion, hopefully you find the best path to the water, good luck

 

[Venturian1]

From a different perspective....No Spark? un-screw the boots from the ends of the plug wires, snip off 1/4" of each wire, test the resistance of the boots (compare to specs) if good and reasonably equal, put some dielectric compound on the insulation of the plug wires and put the boots back on. Never crank the engine without the plug wires being grounded. This could damage the MPEM. Get new plugs, Check the gap, put wires on and using jumper cables (make sure they are good), clamp each plug in a cable and ground the other ends to bare clean metal (the base of the temp sensor in the head works well, and the neg batt post). cover the spark plug holes with a rag and check for spark in the shade or evening for better visibility. spark should be bright blue. Use anti-seize on the plug threads when installing.
Instead of jumping the start solenoid with a screwdriver, use a jumper wire from the battery to the small red/white wire on the solenoid, this will give an indication of a bad switch or bad wiring connection outside of the box if it cranks better, however, you don't energize the ignition coil just by jumping the starter, so you won't see any spark. the MPEM has a built in ignition module, and, (I think), the start button, with lanyard on, is the only way you're going to get it to fire. And, when these guys say check your oil lines, this is serious, and that means all of them, including the two larger oil hoses to and from the rotary valve shaft I even drain the oil tank, and clean it. You never know what someone has put in there, or what kind of oil they used, and its not a good idea to mix oils, so I drain the oil from the rotary valve shaft enclosure too, so I can start out fresh and clean, and especially do a close inspection of the tiny oil hoses from the pump to the rotary valve cover, and don't fail to calibrate the oil injection pump right after installiing the carb(s), its actually quite easy using a mirror. Those tiny oil hoses have little hose clamps and can be loosened with a pair of pliers, and new hoses put on then tighten the clamps with a pliers by pinching the ends. Your one bad cylinder obviously overheated, you will see a stuck ring or two on that piston, and what causes that? lack of injection oil mainly, but running the engine out of the water without a water hose connected will overheat one also. (Which reminds me... once its running, disconnect the wire from the temp sensor and ground it. Your buzzer should sound an alarm. This checks the circuitry and buzzer, but not the sensor. To check the overheat sensor it must be removed and placed in a pan of hot water with a thermometer. Use an ohmmeter. When it heats up, it grounds the wire, check the specs to find out at what temp this should happen) You must run it on premix until ALL air bubbles get purged out of the oil lines. Here's how I do it: At idle speed (pre-mix in a jug, siphon hose to carb) reach down and move that arm on the injection pump forward as far as possible, and watch the tiny oil hoses for air bubbles to get out. It will smoke a bit, but it don't take long to purge the air out this way, and don't fail to connect a water hose to keep it cool

 

[artr]

In terms of determining if the MPEM is good and determining no spark I would consider the following. I have done resistance measuring on 3 different CDI units for my jetski and none of them matched what was in the manual but all turned out to be working. Your reading look ok because it says certain readings should be greater than high resistance values. The reading you got on some lines was OL which is infinite resistance and greater than the values listed. Does your ohmmeter have a Meg ohm scale or 100 Meg ohm scale. If so then try that.
The recommendation to cut back the plug wire is worth while especially if the resistance measurements for the plug lines are not to spec. Also, I think the MPEM is receiving a timing signal to fire the plugs from the generating coil. I think it is an AC current signal and if not present then the MPEM will not drive the ignition coil. The manual should have some resistance tests for the generating coil. I'm not sure if this is a valid test but put a 12V test light on that generating coil output line and see if you get it to flash while the engine cranks. Also make sure that it make it to the MPEM input.

 

[Venturian1]

Just because you paid only $200 doesn't necessarily mean its totally shot. I bought a double trailer for $400 a while back, and when I got to the sellers location, saw it had a ski on it. The guy said oh, it comes with the trailer. turned out to be a fine running ski with 150 psi on both cylinders of its 787cc engine after a few basic repairs. all fuel issues. So don't loose hope. just be thorough and double check everything. Never assume all is good. example: squish gap. check it before removing the cylinders so you'll know what thickness of base gasket to buy. Fuel sys: don't use those $10 rebuild kits from ebay. get quality OEM and follow the rebuild instructions they post on this forum, and if you don't have one, buy a pressure/vacuum hand held pump, it makes life much easier. Use it to check the fuel tank vents, fuel selector valve, pop-off pressure, fuel pump check valves (built into the carb) and for fuel return orifice. They do get plugged occasionally. Also check the pulse port with it.
Electrical issues that are often not noticed are: oxidation is probably the most common, and not just at a connector. feel and bend each wire to be sure its soft and flexible, ive seen wires good on both ends, yet in the middle its rotted in two. swelling of the insulation and stiffness means the copper inside is reduced to powder. and always solder any repairs and use marine grade heat shrink tubing, trailer wiring too.