93 GTS Crank No Start after fuel filter clean. Ran great before.

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Second compression test results with a different tester, cheap one from Amazon. Both cylinders around 130 psi. It was bouncing between 125 and 130 at WOT, cold engine, both plugs out. One cylinder happened to stop the needle at just over 125 the other right at 130. The loaner tester from Autozone was not bouncing like this and ended up at around 135 on both.

 

[burtshaver2021]

Another thought - it could be the coil is failing as happened to the other 93 GTS that is posted right above yours (won't rev up). It seems more likely for an electrical issue to occur when it's sudden like that (and the fuelling part is ruled out). I'm more familiar with snowmobile repairs & have sometimes used a timing light to see if the spark is failing under load.

Hi Doug, are you able to explain how you use the timing light to see if the spark is failing under load? I have never even touched a timing light so I may not understand

 

[etemplet]

If you haven't found it yet you have a fuel problem. Pressure the system to 10psi and verify no leaks with the fuel selector. You have to pinch off the lines at the baffle. You may have an issue with the carb fuel pump. Is there any liquid behind the pump diaphragm? Another biggie. Check your main diaphragm (the big black one) Might have a pin hole or it might just be sticking. Check your pop-off and the carb needle. Is the filter clean inside the carb?? They can get coated with varnish and not allow enough fuel to pass. Good Luck !

 

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Pop-off test results:

Pops at around 27 psi which seems to be within the spec (21-32 per shop manual)

 

[burtshaver2021]

Pop-off test results:

Pops at around 27 psi which seems to be within the spec (21-32 per shop manual)

Seadoo source says 21-37 which still puts you in spec, any leaks from the needle or seat when you were doing pop off? Happen to see what it re seater at? Did you pressure test after you got it all back together?

 

[DougtheSlug]

Hi Doug, are you able to explain how you use the timing light to see if the spark is failing under load? I have never even touched a timing light so I may not understand

You just observe the flash of the light and see if it cuts out when the engine is dying. It's possible to do this with a in-line spark tester but it is a lot harder to see. The other trick is to use a spray bottle of gas and shoot into the intake to determine if it's starving for fuel. A lot of times it's tough to know if it's a lack of fuel or spark that's the issue.

 

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Seadoo source says 21-37 which still puts you in spec, any leaks from the needle or seat when you were doing pop off? Happen to see what it re seater at? Did you pressure test after you got it all back together?

Took apart, cleaned and tested the carb again in accordance with the manual, step by step. All checks out.

Took the rotary valve cover off and did the solder test as described in the manual below. My measurement is 0.017 so seems to be within spec.

A different problem. When I took the cover off, the rotary valve itself came off the shaft so now I need to figure out how to put it back on correctly before assembling it all back up. Shop manual says I need a degree wheel and the TDC gauge to do this and has several steps. Is there an easier way to get this right?

 

[burtshaver2021]

I am baffled, fuel system all checks out after pressure testing, no leaks, carb has all been rebuilt with Mikuni , needle and seat aren’t leaking and popping correctly, compression is ok, , spark is good, rotary valve is good? I haven’t checked the specs myself. I’ve never had the rotary valve off so I couldn’t help you. If @mikidymac or @etemplet or someone else who knows doesn’t come on to help try posting a different thread for the rotary valve.

 

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I am baffled, fuel system all checks out after pressure testing, no leaks, carb has all been rebuilt with Mikuni , needle and seat aren’t leaking and popping correctly, compression is ok, , spark is good, rotary valve is good? I haven’t checked the specs myself. I’ve never had the rotary valve off so I couldn’t help you. If @mikidymac or @etemplet or someone else who knows doesn’t come on to help try posting a different thread for the rotary valve.

Well, I really made sure to follow all the steps in the manual when cleaning and testing the carb this time vs just watching a video as I did before. I'm pretty confident that the carb is good to go now. So this might have solved the problem but I can't test until I figure out how to put the rotary valve back on correctly!

 

[SIMPLEARKANSAN]

There are Youtube videos that will show you exactly how to re-install. There is a tool that you use or you can make your own out of paper.

 

[POPPS]

burt is correct,,,check compression,,,could be fuel related maybe flooded carb?

 

[mikidymac]

Rotary timing has to be exact. You really need even a cheap dial indicator to get it to TDC and you can print and cut out a paper degree wheel from the service manual.

 

[etemplet]

I am baffled, fuel system all checks out after pressure testing, no leaks, carb has all been rebuilt with Mikuni , needle and seat aren’t leaking and popping correctly, compression is ok, , spark is good, rotary valve is good? I haven’t checked the specs myself. I’ve never had the rotary valve off so I couldn’t help you. If @mikidymac or @etemplet or someone else who knows doesn’t come on to help try posting a different thread for the rotary valve.

I made a video of that and posted on youtube. Here YA GO !!!
Gene's Rotary Valve Timing Video

Easy Peasy.

 

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I made a video of that and posted on youtube. Here YA GO !!!
Gene's Rotary Valve Timing Video

Easy Peasy.

Easy Peasy indeed! On this 587 motor Seadoo put a timing mark right on the case - the little triangle reflecting in the mirror in the pic below. I made my own degree wheel out of a CD to double check and sure enough this mark is right at 130 degrees as per the specs.

 

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SOLVED!!!

I wish I knew exactly what fixed it but the ski is running better than ever. Super crisp throttle, quick take off, smooth transition, not a hint of bogging at any RPMs. Idles at 1500-1600 as long as you want, WOT at 6300. Ran at just under 40 mph solo and 36 mph with my son at WOT according to the GPS.

When I finished putting it all back together (rotary valve, carb) and took the ski to the water yesterday it started right up and ran just fine up to about 4500 rpms and then it would bog. At this point I realized that my High Speed screw was several turns out. I screwed it all the way in and problem solved. So that's definitely something that I completely missed.

Then I ran it for 45 minutes straight and it was working great. I headed home and all of a sudden it wouldn't go past 4500 rpms again. Put it back on the trailer and called it a day. Found a few pine needles in the impeller, but didn't seem enough to cause this. I was also close running low on gas, not yet on Reserve though. Should these skiis run at 100% all the way down to reserve or is it possible for the power to be cut like that due to low fuel?

Anyway, today I checked the fuel filter and there were just a few small pieces of black hose gunk in there. Cleaned that and also noticed that the ebay filter I put didn't fit tight (it did before) and was sort of caving in like a plastic bottle under vacuum (was straight when I installed it). I switched back to my old filter which is in good condition, fits tight and looks straight.

With a full tank of gas my son and I took the ski out today. It ran perfect the whole time we were out (just over an hour).

I'm not 100% sure it's all good until I got through at least one tank of gas, but so far so good and fingers crossed.

Can't thank you all enough for sticking with me through all of this and I will update this thread as things progress. Not many ski days left this season unfortunately!

 

[etemplet]

Good Stuff !!!