What am I doing wrong??

[Mitchapalooza]

Hi Folks,

I've been lurking on the forums for a while now and I have to say the posts/advice that I've looked at so far has proven extremely helpful in getting me this far - so thank you all very much! Also, thank you in advance for any responses to this thread. Your advice and opinions are valued heavily.

I have a 1992 SeaDoo GTX Bombardier (white 587 Rotax) that my dad purchased back around 2000. We used it for a couple of years until there was some kind of issue (too long ago to remember exactly) and we put it in storage. Completely forgot about it until a month ago when we were cleaning out our storage buildings and I decided to see if I can get her running. I was successful in getting it started several times and opted to take it out to the lake yesterday to get some time in. However, when I got it in the water, it would not ignite. So far, I have done the following, though I'm new to working on these engines and am not sure what the next step is to get it running well/reliably.

First, I pulled the carbs (dual Mikuni) and did a full rebuild on both. They actually didn't look terrible, though I rebuilt them anyway. I used an aftermarket kit from Amazon (I know, should've used OEM Mikuni but didn't want to sink a ton of money into this project) that had multiple 5 star reviews. I reused the original springs and set the pop-off pressure at 26psi on both - tested multiple times.
Tested the oil pump while I had it off and it drew oil just fine. Replaced the two 3/32 Tygon oil lines on the pump.
Replaced multiple fuel lines. The original gray lines had already been replaced with black automotive lines prior to purchasing it, though I replaced any that had any kind of cracking around the ends. The rest look good.
Flushed the fuel tank.
Put brand new battery in it and cleaned the terminals.
There was some oil in the hull and some remained in the lines when I found it. I pumped the oil out and refilled with Walmart Quicksilver Full Synthetic. It is holding oil and I have not lost any thus far except for very little when I primed the oil lines.
Replaced the in-line oil filter.
Put a couple of gallons of premix in only to discover there was no spark. I pulled the electrical box out and took a look only to find that the 15a fuse was destroyed. Tested for power at ignition coil and there was none. Separated the black/red connector from MPEM and got spark and ohm tested entire electrical system, so I found it was a faulty MPEM. Ordered a new one (updated model with fuses built in rather than relays) and instantly fixed spark issue.
Tested start/stop switches and they all check out.
Wasn't getting fuel and found there was pressure relief when I unscrewed the fill cap so I went through the fuel system and found that the pressure check valve on the side of the hull was clogged with dirt. Blew it out and now carbs are receiving fuel - I can see it flowing through pulse valve and between the carbs.
Removed and inspected petcock. Tested it by blowing into the fuel lines in various positions and it appears to be functional. Removed fuel/water separator and o-ring was good. After it started getting fuel, the filter cup filled up, which is good.
Replaced both spark plugs (correct model and gapped at .024) - have good white/blue spark. They both look clean and slightly wet after getting it running.

After all this, I got it started though it was revving away. I put it on the hose and ran it for 15 minutes via the procedure in the manual and it ran okay. It revved away slightly a couple of times, though I pulled the choke slightly and it went back down to around 2000-2500rpm.

Pulled it home and ran it on the hose again for a while. It idled consistently around 1500-2k RPM and after a few minutes it died. I was not able to get it started for a while after this, so I pulled the air intake/flame arrestor just to troubleshoot. Pulled the plugs and cranked on it a bit just in case there was any water in the engine since it died on the hose. It is getting fuel (have used premix to be safe) and good spark. Ran the battery down a bit attempting to get it started so I left it on the charger overnight.
Came out the next day and attempted to start it again. I likely flooded it so I cranked it with the petcock off a couple of times and managed to get it started.
Ran it on the hose again for a while and didn't have any issues.
I brought it out to the lake and after I dropped it, it would not start at all as mentioned above.

These are the issues that I have noticed and could definitely use your knowledge/advice on.
Tested the compression (both with one plug in and both plugs on the grounding posts) and came up with a consistent 118 on the mag side and 120 on the PTO side. I know that this probably means it is time for a top-end job, though it should still at least run at this compression to my knowledge.
When trying to start, there is some visible fuel sputtering out of the mag-side/fuel pump carb. I'm not sure if this is normal or not. As mentioned, I can see fuel coming in from the pulse line and between the two carbs.
So, I have spark, acceptable compression and fuel. I have not opened the magneto cover, left the RV alone when I pulled the carbs/oil pump and the PTO spins a what looks like a normal speed when cranking the engine.

I'm at a loss as to what to do next. Any help would be very much appreciated. Sorry for the long story, I'm trying to be thorough.

Thanks!

 

[mikidymac]

Well I can tell you that you probably wasted your money on the aftermarket carb kits so now you can do it twice. Get OEM Mikuni kits including new needle and seats. It sounds like those crap kits are flooding your engine.

To go with that 120 psi is a the end of the compression scale and will cause it to be very hard to start or no start when in the water.

Alos 15 minutes is way too long to run it on the hose. Even with the old carrier bearing driveshaft seal it needs water from the lake to help cool it.

 

[Mitchapalooza]

I will say that the needles and seats are genuine Mikuni. The gaskets/seals are aftermarket, as I had to order them separately. Sorry, should've specified there. If the pop-off pressures were tested consistently at 26psi and they both held pressure, I can't imagine why the carbs would be flooding out the engine.

I may need to re-test the compression because of a couple of factors. One, I realize now that the battery was not fully charged (tested after I attempted to start it on the lake unsuccessfully. The other is that I did not hold the throttle open while testing. I don't know how big of a difference these factors will make, but if it's 5-10psi, that could be significant.

Thanks for letting me know about the engine run-time on the hose. I rarely run it any longer than 3-5 minutes on the hose, though I wanted to make sure that the engine was completely flushed out and running relatively smooth. Now, I know better.

 

[Cheflen]

I will say that the needles and seats are genuine Mikuni. The gaskets/seals are aftermarket, as I had to order them separately. Sorry, should've specified there. If the pop-off pressures were tested consistently at 26psi and they both held pressure, I can't imagine why the carbs would be flooding out the engine.

I may need to re-test the compression because of a couple of factors. One, I realize now that the battery was not fully charged (tested after I attempted to start it on the lake unsuccessfully. The other is that I did not hold the throttle open while testing. I don't know how big of a difference these factors will make, but if it's 5-10psi, that could be significant.

Thanks for letting me know about the engine run-time on the hose. I rarely run it any longer than 3-5 minutes on the hose, though I wanted to make sure that the engine was completely flushed out and running relatively smooth. Now, I know better.

If there is fuel sputtering out of your carbs your rotary valve could be off timing. I had the same issue with my 95 sp.
As an auto mechanic, timing has always scared me, so I was hesitant to try and mess with my timing, but it was very easy.
4 bolts and the rotary valve cover is off, this can be done with the carb on the rotary valve cover depending on the motor.
I did this with no tools, which may be frowned upon but my sp runs better than any other ski I've had.
After you pull the RV cover off, bring the mag piston to TDC (put a screwdriver in the spark plug hole and see where it reaches the highest point) THEN make sure the opening of the rotary valve is at the bottom of the opening of the intake for the mag side cylinder, this is so you can see the intake on the mag cylinder

 

[Mitchapalooza]

Great minds think alike. After I researched my issue earlier today, I came to the same conclusion that my RV timing is likely off. I was a few beers deep when I pulled the carbs, though I remember that the valve plate may have come off the teeth when I removed the carb bodies. This could very well be my issue. I believe on the 587's, with the mag piston at TDC, it is 147 degrees from the bottom of the "mag side" intake...

I'm looking for a printable template online, though I'm having a hard time finding one. Did you just align your RV plate with the bottom of the opening and call it good? It looks like it should be set around a half inch below this based on other videos...
Thanks!

 

[Cheflen]

I set mine aligned with the bottom of the opening and it has run great for me

 

[Cheflen]

I set mine aligned with the bottom of the opening and it has run great for me

The rotary valves are forgiving and can be off by a few teeth

 

[Digdog]

I wonder if when it is in the water there is just enough back pressure on the exhaust that keeps it from firing up, do check the rotary valves.

 

[mikidymac]

The rotary valves are forgiving and can be off by a few teeth

No, the rotary valves can't be off by a few teeth. The spec is less than half a tooth and is why the valve is eccentric. IF you flip the valve over it will change it by 1/2 a tooth. Find TDC on the MAG piston then install the cut-out paper degree wheel from the service manual and mark it as the manual shows. Your timing will be exact just like it should be.

 

[Mitchapalooza]

Hey Cheflen, I'm glad yours is working well! I didn't really want to buy the transparent RV alignment tool and have been looking for a paper template.
Digdog, this is starting to be my line of thinking as well. I will do it tonight when I get back home.

Mikidymac, I agree with you and, as you mentioned, the RV is asymmetrical and can be flipped over for a .5 tooth adjustment. I've been looking for the paper template you mentioned and found it in the shop manual, so thanks! I believe the 587 is to be set at 147 degrees. I will get my trusty mirror, a couple of cans of patience and tear it apart tonight to ensure it is set correctly. If it is already aligned correctly, I may just pull the carbs completely off since the worst of removal is done and re-check all gaskets, diaphragms, needle seat, filters and pop-off pressure just to rule that out.
I have a sneaking suspicion that there could've been junk in the fuel lines that made it to the internal carb filters. After running the engine a while, I pulled the fuel filter/separator and, though it was full, it STILL had a few small pieces of brown sludge in the bottom. If these were in the lines that were not replaced, some could've easily made it to the carbs and screwed things up.

Thanks a lot, guys. I will report back with what I find on the RV alignment and carbs.

 

[Mitchapalooza]

Mikidymac,
Just looking this over and would like to understand exactly how to use the template, so bear with me. If I'm understanding correctly, I will cut out the 147 degree template from the shop manual. Then, put the MAG side piston at TDC. Place the template with the cut out edge on the right (2 O'clock edge) at the bottom edge of the MAG inlet port, then mark where the other side of the template (10 O'clock) edge is.
When I replace the RV, I'm guessing that it will need to line up perfectly (+\- 5%) with the mark that I made.

Please tell me if that makes any sense at all. The manual specifies using the transparent degree wheel tool to do this and finding/marking the opening BTDC and closing ATDC to obtain correct placement. It does not mention the use of the template as far as I can tell.

 

[Digdog]

Mikidymac,
Just looking this over and would like to understand exactly how to use the template, so bear with me. If I'm understanding correctly, I will cut out the 147 degree template from the shop manual. Then, put the MAG side piston at TDC. Place the template with the cut out edge on the right (2 O'clock edge) at the bottom edge of the MAG inlet port, then mark where the other side of the template (10 O'clock) edge is.
When I replace the RV, I'm guessing that it will need to line up perfectly (+\- 5%) with the mark that I made.

Please tell me if that makes any sense at all. The manual specifies using the transparent degree wheel tool to do this and finding/marking the opening BTDC and closing ATDC to obtain correct placement. It does not mention the use of the template as far as I can tell.

You should use a dial gauge to set TDC along with the degree wheel

 

[Cheflen]

No, the rotary valves can't be off by a few teeth. The spec is less than half a tooth and is why the valve is eccentric. IF you flip the valve over it will change it by 1/2 a tooth. Find TDC on the MAG piston then install the cut-out paper degree wheel from the service manual and mark it as the manual shows. Your timing will be exact just like it should be.

That explains more about the guy I sent my motor to, he lied to me. Then I must've gotten really lucky for my timing to be right lol

 

[mikidymac]

You cut out the paper degree wheel from the manual, not the rotary valve cut out. THe manual will tell you to align some degree with the bottom of the intake port and make a mark then align the top with a different degree and mark it. Then when you put the actual rotary plate on it will fall between those two marks you made with the degree wheel. If it is off 1/2 a tooth just flip it over as the plate is eccentric.

 

[Mitchapalooza]

Thanks a lot, that makes a lot more sense. Should be a lot of fun with it in the hull!

 

[Mitchapalooza]

Nailed it. The RV timing was slightly off and I went ahead and went through both carbs again. The needle pivot arm on the mag side carb wasn't perfectly flush with the housing, so I bent it back slightly and re-tested pop-off pressure on both. Both were at 27 PSI. Re-checked compression with a brand new gauge and it came out to 145 PTO side and 140 mag side. Put it all back together and it fired up instantly and runs strong.

Thanks for the help!

 

[mikidymac]

It's so nice when these work out great. Now go enjoy that thing all summer!