97 GTX Problem has me stumped

[97_Sea_Doo_GTX]

Thanks for the tip. I might just check that next. It is running steadily worse every time I test it out now. The thing is I'm not getting excess oil in the crankcase when it sits but maybe PTO & Mag end seals leaking??

Took it to lake this morning after thoroughly cleaning, inspecting and testing both carbs. It runs perfect in the water at 1500 rpms for about 10 secondes and then the rpms begin to drop. Run less than a minute, died and wouldn't start. let it sit for about 5 minutes. Started right up at 1500 rpms but then they began to drop again until it died again.

Took it home and started it. Idles at 3000 rpms but the rpms again drop until it dies. Took the plugs out and they seem a wet but the spark on each is strong and a nice blue color. For the hell of it I tried a new rectifier. no change.

I decided to disconnect the return line at the Y and see if fuel was flowing to to return. Started it again and there is a decent flow from the returns on the carbs at idle. Tells me this thing is getting fuel.

Here's a recap of everything I've done so far:

- Tested compression multiple times with 2 different compression tester. 145 on both cylinders.
- Pulse line has good vacuum/pressure with my finger over it while cranking. Hose is in very good condition.
- Disassembled both carbs twice. Checked pop off pressure. 36-37 on both. All passages, and jets are clear including the idle circuit passages in the throat. Internal check valves on Mag carb hold in each direction as they should. Set Idle Mix on both carbs to 1 turn and Hi Mix to 0 on the Mag carb and 1/2 on the PTO carb. Fuel pump diaphragm is in good condition. Filters completely clean. I installed genuine Mikuni kits, Needles and Seats a couple of months ago. Ran great at that time.
- Bypassed the fuel selector and water separator. New filter and o-ring in the water separator. Fuel selector is almost new. All black rubber hoses. No obstructions.
- Removed the fuel tank baffle. No obstructions and perfectly clean.
- Installed new NGK BR8ES spark plugs several times. Gapped to .22. Clipped the plug wires and installed new NGK boots.
- Replaced Rectifier.
- Load tested the battery. Good. Charges as it should with about 14.5 volts at about 5500 rpm.
- Drained the fuel tank and put in fresh fuel.
- Pulled the head and no piston/cylinder damage.

I'm at a loss at this point. I'll probably try the leak down test next but the problem has steadily become worse in a short amount of time. I would think if it was a crankcase seal the issues I'm having would progress more slowly. It started out being able to run at 6500 rpms for 30 minutes before it would gradually die but has degraded down to now running for only 30 seconds before the rpms go down until it dies. Total run time in several sessions since this all started and rapidly degraded is about 1-1/2 hours.

 

[Schneid]

Try taking out the main inline fuel filter and see if you can easily blow through it. Sometimes they look fine but it can get very restricted.

 

[97_Sea_Doo_GTX]

I just completely bypassed the entire fuel system upstream of the carbs. Ran it out of water. No change. Starts up quickly and gets to 3000 RPMs then the RPMs start to drop until it dies in about 30-45 seconds. Looks like plenty of fuel going through the carbs as I have the return lines dumping into a can. Good return flow.

 

[esahlin]

You have a frustrating issue for sure!
Heres a little article on air leaks in these engines and conducting a pressure test on the case etc. Could be a possible cause of whats going on with your situation. Hope you can get it figured out.
http://www.groupk.com/tec-airleak.htm

 

[97_Sea_Doo_GTX]

Thanks for the article. I'll do a pressure test and see what the results are. Maybe one of the seals has developed a substantial leak.

This has been a very frustrating problem. I've done everything else I can think with no positive results. In fact, it has gotten much worse.

Thanks to everyone with your suggestions and input! I'm stubborn and will figure it out eventually.

 

[POPPS]

Re: the gray plugs,,,so far,,,in my experiences,,,I have yet to have gray plugs and not have some form of top end damage.

 

[97_Sea_Doo_GTX]

Re: the gray plugs,,,so far,,,in my experiences,,,I have yet to have gray plugs and not have some form of top end damage.

None of what I'm experiencing seems to make any sense to me. Sometimes it seems like it's a lean condition and sometimes it seems like a rich condition. When I pulled the head I couldn't find any sign of damage but I suppose it is still possible there is hidden damage. I'm to the point now that it won't run any longer than 30-45 seconds. Starts up perfectly and gets up to 1500 rpms in the water and 3000 rpms on the trailer then consistently loses rpm until it dies. Much worse now than when this all started. Of course, now I can't check plug condition on new plugs. It won't run long enough.

I'll check crankcase pressure next. Just one more thing to check off the list of my diagnosis. I've tried all the logical things. Time top start looking "outside the box". I have been working on engines for many years, mostly 4 strokes, but have never experienced anything like this.

 

[GGuillot]

Dang, you've tried just about everything. I'd lean more to an air leak somewhere, I found out when 2 strokes have this nothing makes it run right. I went through something similar with a chain saw a friend gave me, he couldn't get it to run right and I struggled with it. Symptoms were about the same, it would sometimes crank up, idle and run fine, but the longer it ran the worse it got. It was a leak with the case halves.

 

[mikidymac]

Sounds like you still have Carb issues and it’s rich. If it was lean or an air leak the rpm would climb at idle not go down and die. Did you replace the needle arms and pins when you rebuilt the carbs?

 

[TJG358]

Thanks for the tip. I might just check that next. It is running steadily worse every time I test it out now. The thing is I'm not getting excess oil in the crankcase when it sits but maybe PTO & Mag end seals leaking??

Took it to lake this morning after thoroughly cleaning, inspecting and testing both carbs. It runs perfect in the water at 1500 rpms for about 10 secondes and then the rpms begin to drop. Run less than a minute, died and wouldn't start. let it sit for about 5 minutes. Started right up at 1500 rpms but then they began to drop again until it died again.

Took it home and started it. Idles at 3000 rpms but the rpms again drop until it dies. Took the plugs out and they seem a wet but the spark on each is strong and a nice blue color. For the hell of it I tried a new rectifier. no change.

I decided to disconnect the return line at the Y and see if fuel was flowing to to return. Started it again and there is a decent flow from the returns on the carbs at idle. Tells me this thing is getting fuel.

Here's a recap of everything I've done so far:

- Tested compression multiple times with 2 different compression tester. 145 on both cylinders.
- Pulse line has good vacuum/pressure with my finger over it while cranking. Hose is in very good condition.
- Disassembled both carbs twice. Checked pop off pressure. 36-37 on both. All passages, and jets are clear including the idle circuit passages in the throat. Internal check valves on Mag carb hold in each direction as they should. Set Idle Mix on both carbs to 1 turn and Hi Mix to 0 on the Mag carb and 1/2 on the PTO carb. Fuel pump diaphragm is in good condition. Filters completely clean. I installed genuine Mikuni kits, Needles and Seats a couple of months ago. Ran great at that time.
- Bypassed the fuel selector and water separator. New filter and o-ring in the water separator. Fuel selector is almost new. All black rubber hoses. No obstructions.
- Removed the fuel tank baffle. No obstructions and perfectly clean.
- Installed new NGK BR8ES spark plugs several times. Gapped to .22. Clipped the plug wires and installed new NGK boots.
- Replaced Rectifier.
- Load tested the battery. Good. Charges as it should with about 14.5 volts at about 5500 rpm.
- Drained the fuel tank and put in fresh fuel.
- Pulled the head and no piston/cylinder damage.

I'm at a loss at this point. I'll probably try the leak down test next but the problem has steadily become worse in a short amount of time. I would think if it was a crankcase seal the issues I'm having would progress more slowly. It started out being able to run at 6500 rpms for 30 minutes before it would gradually die but has degraded down to now running for only 30 seconds before the rpms go down until it dies. Total run time in several sessions since this all started and rapidly degraded is about 1-1/2 hours.

I dont see where you have checked oiling system anywhere, Or do you premix?

 

[97_Sea_Doo_GTX]

The oil pump is working correctly. The marks line up at idle and it introduced more oil when I manually override the lever as It starts to smoke more than normal. The filter has also been changed.

I pressure tested the crankcase today. Per the manual it should hold 5psi for 3 minutes which it actually does. It loses total pressure at about 30 minutes.

 

[97_Sea_Doo_GTX]

Thanks again for your involvement in this issue. I really appreciate it! I'm running out of ideas so I'm listening to all of your suggestions.

I've been through the carbs completely twice and everything is new in both of them. Needles and seats don't appear to leak and good pressure is held after pop off. Both cylinders seem to have the same issue.

I kind of agree that it's getting more rich the longer it runs but why? Both plugs are wet right after it dies. It no longer will run more than 30-45 seconds but initially starts at the correct rpm. It doesnt misfire as the rpms decline and will rev up when first started. As the rpms go down it will not rev up as smoothly.

When it's in the water or on the hose it doesn't even have much time to warm up before it dies. It also starts slightly harder when in the water. After it dies it won't start back up immediately. After a few minutes of will start again and the same routine begins all over.

Do you all agree that the crankcase pressure holding for at least 3 minutes and 30 minutes until all pressure is relieved is typical? I know a leak in the crankcase would cause a lean condition but just trying rule out as much as I can.

 

[POPPS]

Even though you pulled the head and saw no damage,,,you cannot see if you have a stuck ring, or piston damage,,,those gray plugs to me suggest something is not right "down under".

 

[97_Sea_Doo_GTX]

I MIGHT have solved the mystery last night. Thought I'd replace the coil just in case it was acting up. it tested good but coils are cheap enough so I ordered one. I started it up on the trailer and it seems to run much better and doesn't drop the rpms and die. I'm going to try and get it to the lake tonight and test it.

I'll let y'all know how it goes.

 

[97_Sea_Doo_GTX]

Took it to the lake tonight. Started out running pretty good. Got up to 6500 RPMs and then started losing RPMs again. After about 20 minutes it had a difficult time getting over 4500 RPMs and then declined quickly until it wouldn't idle without feathering the throttle. Agreed exactly the same as when the problem originally started.

These are new spark plugs and how they looked after this run. They look like their running rich now. The Left plug is the PTO and the right is the mag.

 

[mikidymac]

The plugs still look richer than I would expect. I still think you have a carb issue ut not sure what it might be.
1. Correct 80 gran black springs?
2. New needle arms and pins?
3. Mikuni needles and seats?
4. Mikuni kits.
5. Pop-off and leakdown passed?

I know beating a dead horse......

 

[97_Sea_Doo_GTX]

The plugs still look richer than I would expect. I still think you have a carb issue ut not sure what it might be.
1. Correct 80 gran black springs?
2. New needle arms and pins?
3. Mikuni needles and seats?
4. Mikuni kits.
5. Pop-off and leakdown passed?

I know beating a dead horse......

Yeah it is frustrating. Everything on your list is new and the pop off pressure and leakdown tests came out well within specs. The springs are the original black springs.

I'm now feeling more like it has an ignition issue. The new coil at least got it to run for a longer period of time and the plugs look like they could be rich due to week spark. I ordered a new stator and will have it next week. The research I did on symptoms of a bad stator include most if not all of the symptoms being experienced.

I'll let you know what happens. Thanks again to everyone! This forum is a great place to get help with problems like this!

 

[97_Sea_Doo_GTX]

Well, I put in a new stator. Took it to the lake and still no difference in how it runs. I've been through the carbs 3 times now with no problems found. Nothing I've done so far has solved the issue.

I've decided to remove the pto flywheel then pull the engine for a complete teardown and inspection. I'm tired of working on this thing so II will probably take a break from it and make this a winter project.

 

[emspjay]

I'm not an expert I just read a lot of stuff here on the forum. Does the leak down test of the engine work for the crankshaft seals? Maybe the crankshaft seals are so gone that it's constantly getting too much oil in the combustion chamber?

 

[97_Sea_Doo_GTX]

Yes, it does test the crank seals. The test pressurizes the entire crankcase. My test came out as acceptable per the repair manual. There's also not a problem with excess oil leaking past the the 2 inner crank seals as would be evident by excessive smoke when first starting or hydrolocking after sitting for an extended period of time

I figure while I've got everything apart I just as well replace the outer crank seals. I might just do a complete rebuild while I'm at it.

 

[emspjay]

Right on, my wife's GTX I now think has leaking seals. It smoked a lot on initial startup. And last weekend when I tried to start it after 2 weeks of sitting it would not start, pulled the plugs and they were fouled with oil and gas. Cranked the engine with plugs out and a bunch of black oil and gas mixture came out. Put new plugs in and ran it for the weekend and then clamped off the oil line so I hope I will be able to use it next weekend. Looks like it's time for a rebuild for me also.

 

[jrl1644]

another shot in the dark... Do you have an aftermarket fuel filter installed? I have had problems with 2 skis doing something like what you are describing, but I never paid attention to the plugs. The skis would run ok for a bit then fall off quickly until they could hardly limp back in. It was caused by using the automotive filters pictured below. They get moisture in the element which then increasingly restricts fuel passage.

 

[97_Sea_Doo_GTX]

Thanks for the idea but I only had the water separator filter. I even by bypassed the entire fuel system and drew fuel out of a gas can. No improvement.

I pulled the motor out today and plan to completely tear it down for inspection. I'll probably just rebuild it while I have it apart. Not planning on getting it back together anymore this season so I'll just take my time with it.

I'll report back if I find any issues that might have contributed to this problem.

 

[97_Sea_Doo_GTX]

OK, I started disassembling the motor this morning and found a problem. The rotary valve cover is heavily scored and worn to the point that it is not even remotely flat. The rotary valve itself is also scored and heavily warped. The block is still undamaged. I assume this could be the source of my problem. What do y'all think?

 

[GGuillot]

OK, I started disassembling the motor this morning and found a problem. The rotary valve cover is heavily scored and worn to the point that it is not even remotely flat. The rotary valve itself is also scored and heavily warped. The block is still undamaged. I assume this could be the source of my problem. What do y'all think?

Usually the symptom is hard starting with a RV problem. Did the RV get changed recently? I've had a new come in from WSM that wasn't flat and it was warped like you show in the pic. I haven't heard of the RV warping like that on it's own.

Yeah, if the case is still good, looks like a new RV and cover is in order.